E38 idle tuning

[hymey]

THIS THREAD OUTLINES E38 IDLE TUNING AND ADJUSTMENTS. PLEASE READ THROUGH ALL FOR INFO IN DETAIL OR PLEASE SKIP TO POST 25 FOR A FASTER SIMPLIFIED VERSION




While the challenge has always lied in perfecting the VVE table I have found getting the perfect idle more challenging. My car has a 218 224 112 cam which is relatively small compared to some setups. It sounds good at idle but to be honest my old 308-LJ idled better with a crane 288 solid cam and 750DP Holley.

While you can get a e38 controlled engine idling well getting them idling very good is more challenging. I have been experimenting a lot getting a decent idle with no hunting, basically the engine idles like stock now with a deep note and I have pulled 10% fuel out as so much was passing through before.

Basically I zero out the airflow correction tables B1845 and B1843. Then use B1829 to adjust throttle percentage at idle. If airflow and TP is correct we dont need much correction. So increasing or decreasing g/s values in b1829 will adjust TP to where you need it for correct idle speed. During this time there will be timing correction taking place keep a close eye on it and use this to help verify if it has to little or to much timing.

You will find at this stage idle is dead smooth if it is not keep working at B1829 to get a decent idle.

B1845 is proportional correction and integral is 1843. Proportional changes are direct adjustments to airflow where integral is a sum of these adjustments. Basically short and long term corrections. I disable B1843 by leaving the tables zeroed out as I previously mentioned. I then build a new table with b1845, this will ensure a dead smooth idle. But one thing. I put in the value -2.00 to all the cells in this table and it consistently reduced TP by around 2.8%, this verifys how much TP it takes away, If you look at the factory table rpms less then commanded idle have negative corrections and rpms above commanded idle have positive correction. I first set mine up like this and it hunted badly. It is ass about. Negative numbers reduce TP so they must be added in the cells adjacent to rpms above commanded idle. I tested this myself and now it works correctly which solves the hunting problem. Once I got this far I zeroed out the under and over timing correction tables and used bidi controls to raise and lower timing to find a happy medium, then re-established the timing correction tables.

cheers

Joel

[hymey]

attachment

b1845 modded is how mine is setup,

the other is factory

[alian]

attachment

b1845 modded is how mine is setup,

the other is factory

Did you ever get it on the rollers Joel. I will save this post 4 when i do my cam next year. Ian

[hymey]

Yeah its been on twice now Ian, first time It was wheelspinning tyres arent the best needed strapping right, second time with mafless tune in(sorted) the clutch slipped under load in 4th, It appears though it is making a lot more torque then the 226/232/114 cam made, Should make equivalent peak power and tonnes more area under the curve with 700nm plus torque at the wheels. A good mafless tune with correct fueling throughout the rev range has what has made the difference with this cam as it shines in the bottom and mid and revs quickly to 6600rpm..

I have done some more experimenting with idle tuning today, This time zeroing b1845 and 43 everywhere and focusing on getting the TP correct. I found it is less likely to hunt as while the etb reacts quickly to idle correction it upsets idle just as fast which is why it takes a little time to get it right. Most logs I have seen of cammed e38s show airflow and timing are both being over corrected to compensate one another and starting from scratch is the best way to do it.

After zeroing b1845 and 1843 I used minimum idle airflow and b1651 max idle area to adjust the tune in open loop. I found sometimes that TP% would vary by upto 2% at idle even though the learning tables were zeroed. Lowering B1651 and increasing B1845 prevents any movement in TP%.

18.8% TP is the max TP% (using ETC.TP pid this is approx 12%) is the maximum allowed throttle area with stock B1651 settings, basically it's a maximum idle airflow, standard is 1.8, Mine is now 1.1 which maximum TP is 16.9%. By increasing minimum idle airflow it has prevented the TB dipping to around 13-14%. I have steadily increased minimum airflow and decreased maximum area to obtain a steady TB position. It doesnt take long to do within a few flashes I had it where I wanted but what I have learnt is that using these tables allows for total control of idle quality, Now idle sounds great with a slight chop absolutely no hunting and drives much smoother from dead still, showing the e38s true ability and tuning big cammed cars with no surging or hunting.

[hymey]

The tables above show before and after adjustments. My car is a manual so the B1652 table can also be used for auto tranny cars. In my case Mine is manual so I have made B1651 and B1652 the same. Lowering these tables definately works and manipulating both B1651 and min. idle airflow is the key for total control of airflow at idle.

cheers

Joel

[joecar]

Ha Ha, LJ with a 308, a "beast"... ;) cool... :cheers:

[swingtan]

OK, I've done some idle tests and spoken with Joel about this. Here's what I've found.

Note: in my OS I do not have B1843, instead I have B1844

B1844: Idle Integral Step Size.
Integral:
essential
vital
important
basic
fundamental
primary
central

B1845: Idle Proportional Step Size.
Proportional:
relative
comparative

Setting both to "0" in all cells resulted in a steady idle, but it would "hang" like a stuck throttle. "Blipping" the throttle would allow the idle speed to drop to commanded, but a gentle rev would bring back the hang. Commanded TPS% ( TAC_PCT ) was 5.1% when idling correctly, but would go as high as 11.8% when hanging. While the idle was hanging, there was some hunting, as the spark timing tried to correct for the high RPM and ended up pulling too much timing. At 11.8% TP, commanded spark was -8.0' while the idle table was set to 13'. Blipping the throttle to return commanded TPS to 5% saw commanded spark at 13'.

Setting Proportional Step Size ( B1845 ) to corse settings, made little change in the conditions above. Idle would still hang and could be corrected with a blip. Tested removing idle spark control and found it would start hunting badly to the point it almost stalled. The corse settings were as follows.

Idle Normal
RPM Idle
Error
-256 -1.500000
-224 -1.500000
-192 -1.000000
-160 -1.000000
-128 -0.500000
-96 -0.500000
-64 0.000000
-32 0.000000
0 0.000000
32 0.000000
64 0.000000
96 0.500000
128 0.500000
160 1.000000
192 1.000000
224 1.500000
256 1.500000


Setting Proportional Step Size to a linear fill, from "0" to -1.5 and +1.5 ( which is close to stock settings )reduced the hang effects slightly, but it would still hang. The fans turning on had nill effect on idle quality at all though. Removing idle spark control again resulted in bad hunting.

Setting Integral Step Size ( B1844 ) to corse settings resulted in a marked improvement, but still a slight hang. Idle was very steady and the hang could be fixed with a blip. Removing idle spark control resulted in minor hunting, but it was controlled compared with the previous test. When the cooling fans turned on while idle spark control was of, hunting got worse, but ws still controlled. When the fans turned off, the hunting all but went. The corse settings were as follows...

LABELS Idle Mode
Idle Normal
RPM Idle
Error
-512 0.035156
-480 0.035156
-448 0.030273
-416 0.030273
-384 0.025391
-352 0.025391
-320 0.019531
-288 0.019531
-256 0.014648
-224 0.014648
-192 0.009766
-160 0.009766
-128 0.004883
-96 0.004883
-64 0.000000
-32 0.000000
0 0.000000
32 0.000000
64 0.000000
96 0.004883
128 0.004883
160 0.009766
192 0.009766
224 0.014648
256 0.014648
288 0.019531
320 0.019531
352 0.025391
384 0.025391
416 0.030273
448 0.030273
480 0.035156
512 0.035156

Setting Integral Step Size to a linear fill from "0" to "0.035" ( each side of the "0" rpm axis ) saw no hang at all. Idle was very smooth and controlled very well. You could see the ECM command a little more air when the fans kicked in, but idle remained rock steady. Removing idle spark control now saw hunting get a little worse and when the fans kicked in with no spark control, it would get runaway and almost stall. This probably indicates that the ECM is over correcting with these values.

What's the difference?

The Integral step size seems to be the "primary" or "base" adjuster for idle air. The Proportional step size seems to have a limited effect, at least in the basic tests done. The descriptions in EFILive simply don't explain the tables in a clear enough way.

How I would use these: I'd probably try zero-ing the proportional tables and then set the Integral tables to get the smoothest idle when "idle spark control" is disabled via the BiDi controls. Then reset the Proportional tables to stock ( possibly -10% ) and re-enable the "idle spark control". I really need to work out what the Proportional table acctually does and when it comes into play. The thing is, that this is the oposite to what Joel was seeing. Perhaps it's an OS difference, or just due to the cam. The main thing is, more work in needed.

Logs of the idle tests are attached.

Simon.

[Chuck CoW]

Good work guys! :cucumber: I'm gonna play with this.

Chuck CoW

[alian]

Joel and Simon, both of u r damn ledgendry with the e38s. helps the not so smart out here havn a go.
Cheers Ian.

[ringram]

The key for me was min idle airflow and VVE for startup.
If you readup on PID systems.
Proportional is like you say direct adjustment, integral is the average over time and derrivative is the rate of change.
When you change a system often its recommended to disable the derrivative. We have no access in the software yet to this. Also they say to reduce the proportional and increase the integral.
This is what I have done and after startup mine is pretty good.
In my book the less you can change the stock tune the better as all tables are interrelated, so ideally you set the right airflow and spark and the rest takes care of itself.

Im going to take a look at the tables you guys mention anyway :)

Ive been tuning a 440 cube LS7 in a HSV-R8 with 23x/23x cam.

[hymey]

Thanks Simon,

I had to give you a call on this to get you logging as you always come up with good results.

Since speaking to you I changed max idle area as I wrote in my post above. Lowering this prevents the idle "sticking" I will post a link soon of it idling with tables zeroed. It was sticking or hanging but no problems once tables were lowered. What is very interesting is the proportional and integral controls as reading the science behind these show proportional is a direct change and integral a sum of those changes but in this case it is ass about. Mine is idling at 7% and has no hunting at all with minimal timing correction, Now I have found correct airflow I will increase max idle area to standard setting and zero proportional control then using integral to correct minor changes.

Ringram would be good to see how your car goes with some idle tuning testing(save ur good tune lol) . Initially I had a few troubles with idle airflow and reducing proportional control helps a lot. Min idle airflow is nothing more than a minimum commanded TP% with max idle area being the above ceiling everything else in between is learnt and correct via airflow correction tables and spark control. Zeroing the tables and changing the other tables is how I was able to find correct airflow,

[hymey]

Ha Ha, LJ with a 308, a "beast"... ;) cool... :cheers:

Its a 355ci now Joecar and lots of fun, pretty scary actually.:hihi:

[joecar]

How much does an LC/LJ weigh... (I'm guessing about 2400 lbs with the 202, so with a 308 only a little more)...?

[joecar]

And I am sorry for the hijack... :D

[hymey]

That car weighs 1180kg/2596 pounds.

cheers

[alian]

That car weighs 1180kg/2596 pounds.

cheers

Wow, That would be scary:shock:
Ian

[gmh308]

How much does an LC/LJ weigh... (I'm guessing about 2400 lbs with the 202, so with a 308 only a little more)...?

My 308 XU-1 had 1220kg (2685lbs) on the rego papers, probably a full tank of gas made it a little heavier than Hymey's when it went over the weighbridge.

Great work here on the the idle quality!

Happy New Year all!

[hymey]

With the Top loader and 9 inch and full tank it was 1180kg with the turbo 400 it was over 1200kg from the extra weight and fluid and the car had weight reduced elsewhere. The new owner has put the stroker in it I went for a run a month ago and it hits very hard when the throttle is smashed runs 10s no bottle. I mini tubbed that car myself, done all the work and wish I still had it.

As for the idle its running nicely. I have zero in all the correction tables. And I narrowed the gap between min. idle airflow and max idle area. It is a relatively simple procedure once you get the gist of the tables. There is no set desired airflow adjust, only a bottom and top airflow limit and correction in between, which is why it is possible to obtain a better and smoother idle with more control. Or like Simon has done...play with integral tables for minor correction. If you zero the correction tables it is a must to reduce max idle area down to control TP%.

HAPPY NEW YEAR

Cheers

[swingtan]

I just thought I should remind people that are trying these idle tuning tables, that you need to tell the PCM to skip the idle relearn process after a flash. Before starting the car after a flash, turn the ignition on, then press the throttle to the floor 6 or 7 times to skip the idle re-learn process. Then start the car as normal. If you don't do this, you risk tuning th idle relearn process its self and not the idle its self.

Simon.

[hymey]

Here is some info on PID controllers, You plug in a commanded number into the calculus equation. It looks difficult but is relatively simple calculus.

http://www.engin.umich.edu/group/ctm/PID/PID.html

These type of controllers are a patented design.

Earlier operating systems have tables for all 3 but my car (08 os) only has tables for 2- ie a PI controller.

Plugging in 0 in both tables deactivates the system but to use them effectively numbers must be plugged in both otherwise the equation wont work in some instances. (ie you cant have 0 as a denominator)

There is some examples in the website above which shows how Proportional on its own cannot find a steady state. Integral control will stabilize to steady state faster, and derivative prevents overshoot(but of course a derivative is the outcome of a function in calculus), Integrals are also know as antiderivatives.

The e38 has a lot of mathematics in there and it is all engineering/university stuff above high school level.

When seting up a P-I-D controller

1. Obtain an open-loop response and determine what needs to be improved(ie zero tables)
2. Add a proportional control to improve the rise time
3. Add a derivative control to improve the overshoot(some os do not have this)
4. Add an integral control to eliminate the steady-state error
5. Adjust each of Kp, Ki, and Kd until you obtain a desired overall response. You can always refer to the table shown in this "PID Tutorial" page to find out which controller controls what characteristics.

[ringram]

Any idea of what min idle airflow at the higher rpm's do?
Ie 4000rpm?

Is that for coastdown or what?

[alian]

[QUOTE=hymey;84988]Here is some info on PID controllers, You plug in a commanded number into the calculus equation. It looks difficult but is relatively simple calculus.

http://www.engin.umich.edu/group/ctm/PID/PID.html

I have read through this site 3 times now and the lightbulb still hasnt gone off:doh2:
I will have to read it some more.
Cheers Ian

[hymey]

Yeah min idle airflow at higher rpms, controls coast down, the rate of speed at which engine rpm drops.

Its good to use to control the rate of speed at engine rpm drops especially at 1500 > 800 rpm. If it drops to quickly in this area it is most likely to hunt.

Don't look into it to far Ian, It basically describes the relationship of Proportional and Integral control.

Reducing the proportional tables by around 20% and increasing the integral tables is a good place to start. But with a stock cam leave it alone. Holden have spent enough time setting this up and it is only when you fit an aftermarket camshaft that they will require tweaking.

[alian]

Yeah min idle airflow at higher rpms, controls coast down, the rate of speed at which engine rpm drops.

Its good to use to control the rate of speed at engine rpm drops especially at 1500 > 800 rpm. If it drops to quickly in this area it is most likely to hunt.

Don't look into it to far Ian, It basically describes the relationship of Proportional and Integral control.

Reducing the proportional tables by around 20% and increasing the integral tables is a good place to start. But with a stock cam leave it alone. Holden have spent enough time setting this up and it is only when you fit an aftermarket camshaft that they will require tweaking.

Thanks Joel,Trying to get my head arruond it before I do a cam. Have been in maffless 4 some time now but seem to have a problem with coast down. It sounds like it is dropping revs to quick and then recovers. hard to explane, it is if as the auto changes down a gear it sruggles 4 a sec under load.Thinking reading this might give me some insight into the problem.
Cheers Ian

[hymey]

Any idea of what min idle airflow at the higher rpm's do?
Ie 4000rpm?

Is that for coastdown or what?


More on this...It appears that min. idle airflow is not used at higher rpm. B1651 and B1652(in autos) is the max idle area, The stock setting is 18.8% TP%. In the tune this is around 1.89. So as soon as you lift the throttle you will see 18.8% in the log which is around 12g/s in min idle airflow. Only if min idle airflow is less then max idle area it could command less throttle at higher rpm. It will control the rate at which rpms drop on coast down and clutch in.

In a cammed car or stroker it would be a wise idea to raise max idle area starting at 2.00 and go from there, you will see how much TP it commands when you back off at cruise. Then you can raise min idle airflow to close the gap between min. idle and max area. For eg set min idle airflow at 11.00g/s at idle. Then set B1651 to 2.00. The PI controller will then learn between around 17 and 19% throttle. This is an example on how it works and unless you raise the max idle area from stock you may run into trouble with hunting issues. By raising min airflow and max area (narrowing the difference) via experimentation, the PI controller has enough room to work and correct idle speed error it will adjust in steps of around .4%. So if idle is hanging and timing is low it is worth lowering max idle area slightly or if the idle dips to much raise min idle airflow.

If min idle area is raised to high(ie 14g/s) and max idle area is stock setting, max idle area will overide rendering the PI controller useless.

I have two tunes, one like above and the second with zero learning. The factory PI controller works well although a PID controller would work better and be easier to setup. By using the standard PI tables and getting the TP% idle limits sorted is an excellent starting point.

Using an "open loop" setup for e38 idle is simple. Max idle area will overide min idle airflow if the later is commanded higher then max idle area(B1651). For eg, set min idle airflow to a high number like 15g/s, so max idle area takes control of the TP, it is locked in at what ever you command. Experiment with idle area until it sits where you want it. Factory setting is a good start, then work out roughly how much timing you need. ie 18 deg idle timing, and 1.30 idle area will give you 18.4% TP. This is how my car is setup and works great. If I tap the throttle now I get no annoying surges associated with having max idle area(to much airflow) to high in a closed loop arrangement.

For an automatic increased airflow is required once in Drive and foot is on the brake. In this circumstance B1652 comes into play. Again if min. idle airflow is higher then B1652(max idle area 2). The later will overide it and the pcm cannot command higher then B1652. So if I command 1.30 at idle in neutral and 2.20(eg) in gear, when I shift from N to D idle TP% will increase from 18.4% to x amount(eg 21% or what u desire) and if the brake is released the car will drive forward. To get this right again would require experimentation but tuning my car in open loop has given more more control and it runs a lot smoother and economy has been better in stop start traffic.

The best way to go is to tune in open loop first and get familiar with the tables, see what the engine likes(ie 18.3% TP idle). Then add a percent on either side for idle TP% limits, For eg 17.3% to 19.3% TP by manipulating B1829 and B1652. Then reapply the factory PI controller values in B1843 and B1845. The idle should be pretty decent and then these tables can be experimented with to help with hunting.

[ringram]

Nice thread. Im going to throw a little hypothesis in.

Im thinking that transient is the new follower and coastdown the new cracker equiv.
So the idle tables with the 3 columns relate to static idle, coastdown/cracker and transient/follower

Ive been messing with these tables for weeks, though only one or two changes a day.
They can drive you a little insane, I do think the stock P settings cause some nightmares, a look into the hsv r8 tables shows some columns to be zero'd out as are different ones in the Z06 tune.

If you get pissed wipe out the P tables, then as Hymey says add them back once you get the rest done.

Perhaps we can come up with a 10 point plan for tuning idle like the old Desired airflow days.. It may also be the case that the E38 is actually a PID controller and we just dont have access to the D function. Or do you know its actually not there Mr H?

[swingtan]

Good idea Ringram. These E38's can be tricky at times, but probably no more tricky than the LS1 in the early days. If we can get some basic processes down on paper, it should make things a lot easier.

In the L76 tunes, the settings are a little different than the VE L98 tunes. For starters, MAX Idle area is already at 2.2 which according to my TPS graph is about 21% real. I've also noticed in some latter tunes, that the "Transient" column is not displayed at all. The second point also means that there are no transient "limit" settings to adjust ( B1835 - B1842, depending on OS ). These limits can also be used to control how much effect the integral and proportional controls make.

The theory here is that you can alter the maximum amount of correction each component can command, both positive and negative. I'm guessing that these will act more like a soft limit per PID rather than the hard limit of B1651. You can use these to restrict the effect of say, normal idle, but allow coast down or transient to have a wider range of control. So, I'm guessing that if you alter min idle air flow, you should probably check these limits as well as they may mask any increase in B1829.

Simon.

[hymey]

On the VE OS the max idle TP% is 18.8% and on L76 it is 21%. Which the later is more ideal for a cam swap.

There is no desired airflow which is a commanded TP% and then the pcm trims the idle from the desired position.

The E38 has a low limit and upper hard limit. Any min idle airflow figures above b1651 are ignored so it will command 18.8%(factory L98 settings). I have my idle perfect now. The trick is to use B1651 to find a desired airflow whilst zeroing the airflow correction tables. Run the min idle airflow tables to around 25g/s so they are ignored. And then manipulate b1651 until a steady idle is reached with timing in the correct region(say 20 degrees). Once you have found a desired value for b1651 "eg 2.20 area which is 21%" then turn on the aircon and see how it reacts. At this stage leave timing correction on. 2nd stage is to enable correction tables. Then set max idle area so it is slightly higher then the desired amount which may raise TP% upper limit to 21.4%. Also reenable to standard min idle airflow tables. Start the engine and watch the commanded TP% on coast down (which will always be max. idle area). Take notice of how rpms dip, also taking into consideration of timing correction and settings. Check it a/c on and off as it will dip slower a/c off.

Once you are satisfied with the upper limit find the lower limit. Which can be done driving a/c off and with stock correction tables enabled. Start the engine then log after the idle has settled, Go for a drive and then experiment to find what the lower limit is. You dont want it to low as if it overshoots on correction TP% will only drop so far. You only need a narrow gap in TP% limits. An example would be to have a lower limit of 20.0% and upper limit of 21.5%. Which is plenty to correct small changes in idle speed and eliminate hunting.

Last is to setup airflow correction. I take about 50% away from the stock proportion tables. And then as simon suggested, use a linear arrangement in the integral tables. The factory integral table will cause overshoot..... a linear arrangement is more effective. The upper parts of the integral table can be .05-.06 which is roughly .5% of correction then tapering to zero with a perfect linear graph. If you take notice with the stock table it isnt linear at all so slight errors in idle will cause larger fluctuations.

You can have excellent control with the e38. Using the above techniques it is possible to have a very choppy idle or very smooth idle both well mannered. Manipulating the airflow limits and timing can give you just that. More airflow-less timing is a choppy idle and vice versa.

It is very much trial and error. But as ringram has suggested small changes daily will reap rewards and once familiar with the tables it is a simple process.

It is hard to put it in steps but generally first off...

1. Find desired TP% using b1651 max idle area and zeroing correction tables.

2. Once you have found this by testing with a/c on and off reenable correction tables and stock airflow tables and then commanded a slightly higher max idle area then desired and test rpm dipping revving the car in neutral again a/c on and off. Find a happy medium.

3. Next we try to narrow the gap between min idle airflow and max idle area so there is a difference of approx 1.5-2% between the upper and lower limit.Set min idle airflow to 10g/s as a starting point at desired rpm. The low setting is easiest found driving with a/c off, higher then usual timing taking notice of the lowest idle limit achieved in the data tables. (please start logging once idle is settled as it will record a lower limit.) We end up with for eg a bottom limit off 19.5% and top limit of 21.5%.

4. Everything between these limits is learn't and idle steadied via the PI controller on the electronic throttle body and also timing correction. Timing correction will be minimal, and then adjust proportion and integral tables. Proportion is reduced and a linear integral table is built.

5. Automatic cars only. B1652 is max idle area for D/R. Select drive and watch what TP% is commanded adjusting the value in B1652 to a desired airflow is reached. Please note that B1651 max idle percentage can only be tested whilst free revving in neutral or park.

6. Once tables are set up effectively, the timing correction tables can be dulled down. At 16 deg over idle it could be 0 or -0.5 instead of -1.5(around stock). This way we are relying on the airflow correction to trim the idle. Timing correction is fast and if it pulls timing to quickly to drop idle rpms to commanded idle speed, airflow will stay high at the top limit until it settles for a few seconds which then it will fall midway(eg 20.5%). After the timing tables are redone and dulled somewhat the airflow and timing correction will both share an even amount of correction in obtaining a desired idle speed with consistent TP% and ignition timing. It is easy to notice if the timing is doing to much as the idle will be a little choppy till it settles. You want to see the idle settle midway between the upper and lower limit. If timing correction is to aggressive it won't do this, the whole purpose is to let the ETC do its job without over compensating with timing correction which is largely a common mistake.

All in all the purpose is to maximise control over the e38s settings(via the limits) whilst still being able to retain a certain amount of the factory learning capabilities for minor airflow corrections. I hope I have shed some light on the topic. If I have wrote anything confusing(from my poor grammar) please just pm me.

cheers

Joel

[odd boy]

hmmm, I'll try it soon. and get u the result.

[hymey]

Since this has been made a sticky, I have decided to follow on here. Basically I went in deep initially and maybe made things to confusing.

I have decided to simplify this. After helping Ian "alian" with his L76 idle today I thought it would be best to outlay some points. There is only a handful of steps and less then ten flashes of the pcm to obtain a rock steady idle.

The only complaints I ever get are that the 230s cam sounds like a 220s cam or 220s cam idles like stock.

The e38 has an amazing ability to control idle. Once idle is in place and correct everything else can fall into place. I know most people on here know how to tune afr and timing well. Idle is tricky but really its simple to obtain.

The first thing is to think old school. I am unsure how many of you guys have tuned an old small block with a dizzy. I can remember how good they idled for a basic carb and a set timing figure. Basically I am pointing out that very bland simple adjustments are to be taken in order to get the idle 99% right. Then altering some of the tables for drivability can be taken.

The purpose of this thread is not to setup throttle followers or crackers. The e38 is missing these. But in getting the idle correct, these characteristics fall into place and then the tables can be slightly changed in order to get a desired result.

Step 1.

Drill a small hole in the throttle blade, 3 to 4mm, depending on the size of the cam. For stock cams bypass this step.

Reason for this is that the ETC TB only trims 0.4% at a time, this can be heard with the engine idling and in some cases a 0.4% change is to much and causes hunting of up to a difference of 100rpm. The min adjustment is 0.4% regardless of integral or proportion adjustment.

This procedure isn't done to correct a bad idle , increase idle air or for plain sillyness like some do with LS1 TB but its to create a air bypass, A buffer ie if the throttle trims it's an abrupt airflow change and with a small hole some air will go through this and some will pass the edge of the butterfly it smooths airflow changes in TB movement and somewhat decreases the trimming effect of airflow and buffers the air movement which in our case is a good thing.


Step 2.

B1651 and B1652 these are both max idle area tables. One is for automatic transmissions when in gear the other for in neutral. I set these the same values. Having a higher max idle air for autos in N isn't required, min idle air covers this and also timing correction, The hard limit in the e38 is much lower then both the factory values anyhow.

We have to adjust this, it allows the correct idle airflow to be obtained.

In order to do this "min idle air" needs to be maxed out to 63g/s so that the pcm uses max idle area as its Throttle position %. So set B1829 "min idle air" to 63 throughout the table.

Next start by entering 1.10 in b1651 and b1652. This is a good starting point.

B1844 and B1845 set to zero throughout the whole tables and save(please keep a copy of your current tune to keep these values we need them later)

Run standard timing corrections and keep spark to around 15 degrees for testing at idle.


Start the engine(warm up) and log timing and airflow, remember these work together. Please use STFT's aswell as it will trim fuel as idle vacuum improves.

If timing is being corrected to low ie around 5 degrees. We know that max idle air is to high, it needs to be decreased. Also turn on a/c and watch the timing it will increase a few degrees. If the car is an auto put in in "D" and watch the timing figures. If timing is to high increase max idle air by 0.04 at a time. change by 0.02 when close.

Step 3.

Adjust max idle air up or down to get desired idle and timing. In a manual I would go for around 15 deg idle a/c off and 18-20 a/c on. Auto pretty much the same but in D maybe let it creep into the 20s.

Now we have that right time to get min idle air correct. Min idle air is actually desired airflow. Also it is overdone in factory trim and works well for a stock cam but it needs to be simplified to make the car run smoother and prevent hunting. Once its correct it can be massaged.

Populate the integral and proportional tables I mentioned earlier. In the past I spent much time on these when I realised that its not overly important. To get simple effective results min idle air and max idle air and timing are most important. All that is required is to reduce these values by say 50%. I go into integral and reduce by 50% same as proportional. Even 20% is enough in both. In fact plenty as long as the 4mm bypass hole has been drilled its fine. Ensure these are populated and save the tune.

If min idle air is to high the idle becomes "maxxed out" as I call it meaning that it is set higher then max idle air. eg 10 g/s could equal 1.10 max idle area this isnt always the case but in general its close.

Set the whole table to 14g/s. Yes the whole min idle air table. Start the engine and while logging etctp watch what it says. Please note this is the main value you check while adjusting max idle area and min idle air.

Once the engine is running take note of the TP%. Rev the engine let it settle to idle and see how long it takes for the TP to start trimming. If min idle air is to high it will take 10-15 seconds before TP reduces from the max idle area position and starts to trim. If its to low and min idle air needs to increase. It will trim immediately if it is low. We increase until it begins to max out then we keep those values. Again, when there is a delay in trimming by 10 or more seconds we know it is maxxed out. Experiment with 14 s a starter and likely you will need to reduce some calibrations are different, Generally 8g/s is where it ends up.

Now to finish off the min idle air. Again, this table is overdone. When infact all gears including N and D can be all the same. The table should minorly taper upwards towards higher rpm. Remember as soon as the values are above max idle area ie(what we checked for before) this is the value that the figures are maxxed out and overlooked. So anything over say 12 is a waste of time as its not even used. Not even the GM engineers sat down to work this one out.

So set upto 1000rpm your final value of min idle air that you worked out. ie could be 8g/s. from 1000-1200 go 9 1600 up 10 and 2000 up 12. Again leave all the gears and P N etc the same value. This is ALL that is required here. Keep it simple like this to avoid hunting or overcorrection.

Step 4.

We have established correct desired airflow by using our max idle area to find it. Now we have it right we can slightly increase max idle area. This allows the pcm to learn and trim within a fine limit and allows perfection of idle in all conditions cold and hot start, winter and summer, Also full lock, with a/c on in gear and nice throttle feel with no surging or overshoot.

I have found over time by tuning a variety of e38 combos from blown to 240s cams on tight lsa to baby cams that an extra 4% add on is sufficient.

So if we first found max idle area for correct idle was 1.10 , our final figure will be 1.14.

This allows more more air at cold start, The factory pcm adjustment will increase min idle air at cold ect by a multiplier. But we need to ensure that we have enough min idle air at cold start to get a nice idle cold. Cold start enrichment here is very important but that's another topic.

Add 0.04 to the figure, If it is not enough add 0.02 more. But generally 0.04 is enough with good enriched afrs cold off 13:1.

This will get your idle correct. Small changes will be required depending on combo and pcm cal. But overall there all similiar outcomes. Max idle area and min idle area always vary from car to car hence why its so important to do a custom tune on each vehicle.

If you are having troubles idle tuning, this will fix the issues. So many tuners believe min idle air solves everything but it doesn't and those cars tuned like that show it because they surge or hunt slightly which is annoying. Some e38s will get the idle right straight up without these procedures but overtime with increased cam overlap mostly the idle has a LTIT effect that learns upwards which is a bad thing. The e38 has outstanding control. Why not use it and get it idling better then that small block? My 240-242-111 now idles like a 220s cam in a LS1 so give these a try and you maybe want to try that bigger cam. Please feel free to pm me on any of this stuff.

[joecar]

Hymey, thanks for the follow on update... :cheers:

[alian]

Wow. is all I can say!!! Thanks heaps Joel for taking the time and puting it in tradesman terms that I could understand. I have a couple of tweeks to go but the car idles like a stocker. Its a 224/224 on a 114.And the inprovment is out of sight. Make sme think a larger cam might be on the way. lol
Cheers Ian

[gmh308]

Say yah! :) Great post Joel!

[Tre-Cool]

I just spent the last hr doing mine, See how she goes in the morning. I often have problems with the car stalling when i go from park to reverse out of my drive and have to foot brake and touch the go pedal.

I've noticed straight away that my spark idle is much more steady and no longer jumping from 15 to 5 degree's spark and sits nicely around 14'ish.

Thanks again for sharing Joel.

[hymey]

Thanks guys. I have learnt more on idle tuning over the past 6 months. Once hot running ilde is correct. We work on rpm dip. Ie rev the engine and watch how long it takes to settle. This is better to be slower then fast. It should gradually settle to idle. This prevents hunting to occur AND the rpms reduce slower on gear changes so the synchros have more time to catch up in M6 transmissions.

I will add some more to this looking at Cold start to the previous post. Just on a light note. What we find is that the engine needs cold start enrichment of 12.5 to 13.0:1 initially, and also in hot start.

Also timing needs to be looked at. There is a table that covers ECT add on for timing. If you start the engine in the morning and it needs more air, it is idling lower then commanded rpm and timing is high we can add on a substantial amount of timing similiar to what is commanding, also increase max idle air by a further 4%. Overall any changes that occur will require the idle to relearn which after several keystarts and driving it gets better and the long term trims will adjust precisely to what is required. So once the initial idle tune is in drive it for a couple of days and take not of what needs to be fine tuned before taking anymore major adjustments.

[ringram]

Step 1.

Drill a small hole in the throttle blade, 3 to 4mm, depending on the size of the cam. For stock cams bypass this step.

Reason for this is that the ETC TB only trims 0.4% at a time, this can be heard with the engine idling and in some cases a 0.4% change is to much and causes hunting of up to a difference of 100rpm. The min adjustment is 0.4% regardless of integral or proportion adjustment.

Nice post mate, though Id argue that if your min airflow was correct you would be getting the required airflow past the blade anyway so wouldnt need to drill it.

I think your comments helped me sort out a cold start issue I had. It was 2 fold. First max area was set too low and secondly I was cutting too much timing out in the startup flair table.

[hymey]

Nice post mate, though Id argue that if your min airflow was correct you would be getting the required airflow past the blade anyway so wouldnt need to drill it.

I think your comments helped me sort out a cold start issue I had. It was 2 fold. First max area was set too low and secondly I was cutting too much timing out in the startup flair table.

I appreciate your concern over drilling the throttle. What I stress is what I have written. The purpose of drilling it is not to increase min idle airflow. We do this by adjusting max idle air and min idle airflow. Read the post carefully I explain that it is drilled to create a buffer, It is there to create a bypass, when the throttle trims 0.4% with a camshaft the sound of the engine rpm shifting up and down can be heard, while this is OK for some it sounds horrible for me, So when the throttle trims some of the air is continually leaking through the throttle blade hole and only half of it is trimming between the throttle and the body. So it creates a buffer for air basically to take the easy way out but when the throttle trims back it reduces airflow past it and trims the air just nicely. 4mm seams to be on the money even 3mm is OK, 6mm while still OK means the body will have to trim to much back. Also the factory TB only commands 18.8% max in most OS at idle(sae.tp)

Believe me many many hours went into this. How does 2 years of trial and error sound going around in circles. I have been kind enough to share it to everyone for no price but just to cure the frustrations of it all and even if people don't understand why or how it works I have put it in simple format simply because it would take me days to go through it all and there is still more tricks I haven't shared as some of it is irrelevant. So I am very thankful to hear it has helped you. Even if you decide not to drill it thats your preference but if I did it for you and did the procedure I could get the idle better on your car. LS1s are a piece of cake compared to these, many w/s said the e38 was easy but the same cars they tuned had terrible idle. My obsessive compulsiveness drove me to get an easy way to do it so I can nail an idle in 15min before I even start tuning a customers car, Basically not to just achieve an idle but one they desire. I hope I have cleared this up. Drilling it is a very important procedure and the first part of it and not doing so will not achieve an idle to perfection.

But still Richard, thanks for posting and letting me know atleast it come of some help to you even if it was only a small part of it:) I have some more info to share shortly on it.

[calais-346]

Great thread joel, this has helped me cure all of my idle problems, had a lot of undershoot and overshoot problems and stalling when trying to let the clutch out at idle(medium size cam)which i was beginning to think i would need to raise idle speed to help cure.

Thanks for laying it all out step by step too, makes for an easy reference...still having a fiddle to get the idle, and transition to idle perfect under all conditions,i'm willing to bet this thread has helped alot of people get an idle sorted quickly, not just guys like me tuning there own cars.
Jeez the old ls1 pcm was so much less complex than the E38 is

[The Alchemist]

See query below...great explanation helps a lot !!!


Since this has been made a sticky, I have decided to follow on here. Basically I went in deep initially and maybe made things to confusing.

I have decided to simplify this. After helping Ian "alian" with his L76 idle today I thought it would be best to outlay some points. There is only a handful of steps and less then ten flashes of the pcm to obtain a rock steady idle.

The only complaints I ever get are that the 230s cam sounds like a 220s cam or 220s cam idles like stock.

The e38 has an amazing ability to control idle. Once idle is in place and correct everything else can fall into place. I know most people on here know how to tune afr and timing well. Idle is tricky but really its simple to obtain.

The first thing is to think old school. I am unsure how many of you guys have tuned an old small block with a dizzy. I can remember how good they idled for a basic carb and a set timing figure. Basically I am pointing out that very bland simple adjustments are to be taken in order to get the idle 99% right. Then altering some of the tables for drivability can be taken.

The purpose of this thread is not to setup throttle followers or crackers. The e38 is missing these. But in getting the idle correct, these characteristics fall into place and then the tables can be slightly changed in order to get a desired result.

Step 1.

Drill a small hole in the throttle blade, 3 to 4mm, depending on the size of the cam. For stock cams bypass this step.

Reason for this is that the ETC TB only trims 0.4% at a time, this can be heard with the engine idling and in some cases a 0.4% change is to much and causes hunting of up to a difference of 100rpm. The min adjustment is 0.4% regardless of integral or proportion adjustment.

This procedure isn't done to correct a bad idle , increase idle air or for plain sillyness like some do with LS1 TB but its to create a air bypass, A buffer ie if the throttle trims it's an abrupt airflow change and with a small hole some air will go through this and some will pass the edge of the butterfly it smooths airflow changes in TB movement and somewhat decreases the trimming effect of airflow and buffers the air movement which in our case is a good thing.


Step 2.

B1651 and B1652 these are both max idle area tables. One is for automatic transmissions when in gear the other for in neutral. I set these the same values. Having a higher max idle air for autos in N isn't required, min idle air covers this and also timing correction, The hard limit in the e38 is much lower then both the factory values anyhow.

We have to adjust this, it allows the correct idle airflow to be obtained.

In order to do this "min idle air" needs to be maxed out to 63g/s so that the pcm uses max idle area as its Throttle position %. So set B1829 "min idle air" to 63 throughout the table.

Next start by entering 1.10 in b1651 and b1652. This is a good starting point.

B1844 and B1845 set to zero throughout the whole tables and save(please keep a copy of your current tune to keep these values we need them later)

Run standard timing corrections and keep spark to around 15 degrees for testing at idle.


Start the engine(warm up) and log timing and airflow, remember these work together. Please use STFT's aswell as it will trim fuel as idle vacuum improves.

If timing is being corrected to low ie around 5 degrees. We know that max idle air is to high, it needs to be deccreased. Also turn on a/c and watch the timing it will increase a few degrees. If the car is an auto put in in "D" and watch the timing figures. If timing is to high decrease (should this read "Increase" ) just checking :) ???
max idle air by 0.04 at a time. change by 0.02 when close.

Step 3.

Adjust max idle air up or down to get desired idle and timing. In a manual I would go for around 15 deg idle a/c off and 18-20 a/c on. Auto pretty much the same but in D maybe let it creep into the 20s.

Now we have that right time to get min idle air correct. Min idle air is actually desired airflow. Also it is overdone in factory trim and works well for a stock cam but it needs to be simplified to make the car run smoother and prevent hunting. Once its correct it can be massaged.

Populate the integral and proportional tables I mentioned earlier. In the past I spent much time on these when I realised that its not overly important. To get simple effective results min idle air and max idle air and timing are most important. All that is required is to reduce these values by say 50%. I go into integral and reduce by 50% same as proportional. Even 20% is enough in both. In fact plenty as long as the 4mm bypass hole has been drilled its fine. Ensure these are populated and save the tune.

If min idle air is to high the idle becomes "maxxed out" as I call it meaning that it is set higher then max idle air. eg 10 g/s could equal 1.10 max idle area this isnt always the case but in general its close.

Set the whole table to 14g/s. Yes the whole min idle air table. Start the engine and while logging etctp watch what it says. Please note this is the main value you check while adjusting max idle area and min idle air.

Once the engine is running take note of the TP%. Rev the engine let it settle to idle and see how long it takes for the TP to start trimming. If min idle air is to high it will take 10-15 seconds before TP reduces from the max idle area position and starts to trim. If its to low and min idle air needs to increase. It will trim immediately if it is low. We increase until it begins to max out then we keep those values. Again, when there is a delay in trimming by 10 or more seconds we know it is maxxed out. Experiment with 14 s a starter and likely you will need to reduce some calibrations are different, Generally 8g/s is where it ends up.

Now to finish off the min idle air. Again, this table is overdone. When infact all gears including N and D can be all the same. The table should minorly taper upwards towards higher rpm. Remember as soon as the values are above max idle area ie(what we checked for before) this is the value that the figures are maxxed out and overlooked. So anything over say 12 is a waste of time as its not even used. Not even the GM engineers sat down to work this one out.

So set upto 1000rpm your final value of min idle air that you worked out. ie could be 8g/s. from 1000-1200 go 9 1600 up 10 and 2000 up 12. Again leave all the gears and P N etc the same value. This is ALL that is required here. Keep it simple like this to avoid hunting or overcorrection.

Step 4.

We have established correct desired airflow by using our max idle area to find it. Now we have it right we can slightly increase max idle area. This allows the pcm to learn and trim within a fine limit and allows perfection of idle in all conditions cold and hot start, winter and summer, Also full lock, with a/c on in gear and nice throttle feel with no surging or overshoot.

I have found over time by tuning a variety of e38 combos from blown to 240s cams on tight lsa to baby cams that an extra 4% add on is sufficient.

So if we first found max idle area for correct idle was 1.10 , our final figure will be 1.14.

This allows more more air at cold start, The factory pcm adjustment will increase min idle air at cold ect by a multiplier. But we need to ensure that we have enough min idle air at cold start to get a nice idle cold. Cold start enrichment here is very important but that's another topic.

Add 0.04 to the figure, If it is not enough add 0.02 more. But generally 0.04 is enough with good enriched afrs cold off 13:1.

This will get your idle correct. Small changes will be required depending on combo and pcm cal. But overall there all similiar outcomes. Max idle area and min idle area always vary from car to car hence why its so important to do a custom tune on each vehicle.

If you are having troubles idle tuning, this will fix the issues. So many tuners believe min idle air solves everything but it doesn't and those cars tuned like that show it because they surge or hunt slightly which is annoying. Some e38s will get the idle right straight up without these procedures but overtime with increased cam overlap mostly the idle has a LTIT effect that learns upwards which is a bad thing. The e38 has outstanding control. Why not use it and get it idling better then that small block? My 240-242-111 now idles like a 220s cam in a LS1 so give these a try and you maybe want to try that bigger cam. Please feel free to pm me on any of this stuff.

[hymey]

See query below...great explanation helps a lot !!!

There is a bit more work in auto's, If timing is to high and the engine is lagging below commanded idle rpm it is because airflow is to low. In drive in autos, generally the engine needs more airflow as it is pushing on the convertor. This can be done though the min idle airflow tables once you have a desired idle airflow established, which with e38s is very sensitive, 1 to 2 g/s out and they overshoot. I am adding some more info on cold start tonight. What I have found though is that it is very simple to obtain a decent idle with little time spent, And once the correct min idle airflow is obtained max idle area can be returned to factory values. I will go over the cold start info in detail and hopefully help out some people who have asked questions on this and run into problems. Basically the engine should start dead cold with minimum time required for warm up before the car can be driven away with no sluggish or surging behaviour.

[hymey]

I fixed the error! cheers!

[The Alchemist]

Basically the engine should start dead cold with minimum time required for warm up before the car can be driven away with no sluggish or surging behaviour.
now that you mention it, since we have some good fuel numbers HOT in this V8 we are doing, supercharged, cammed new engine VE Ute, I did a cold start yesterday and found it going to 10%+ STFT at idle and had a really doughy throttle response ie not enough fuel.
Is Table B0141 & B0146 the tables to alter to increase fueling during warmup? And why does it appear that its fuel trimming even when under 55degs and been running for about 60seconds from dead cold. Also as the temp went past 80deg the fuel trims went from +10% and quickly went down to a nice -2% (yet the actual AFR richened up (see log)) which is where I had it set hot running from the day before.
Cheers,
Mike

[swingtan]

Do not under any circumstances relay on fuel trims for cold start corrections, always use a good WB sensor.

The E38 has different tables for CL control and for NB O2 "ready". in the stock setup, this means that LTFT's can be applied before the O2 sensors are enabled for "true" CL operation. The LTFT data is learned from previous drive cycles, but of course, if the O2's are yet to be enabled, the LTFT data is not actually correct for the current engine conditions. you will also find that both LTFT's and STFT's will change as the engine warms up, IE. the trim amounts will vary until full operating temp is achieved. This is due to engine efficiency changing as the combustion chamber heats.

{B0141}: This is the base OL fueling table. It's a bit weird the way it's set up, as in theory, IVT can never be much lower than ECT. So if you keep this in mind you can set up the table fairly quickly. Remember that it's only a "commanded fueling" table and should be used try and get the desired fueling, it has no effect on the actual AFR's measured with a WB. Personally, I use this for controlling initial cold start and the first few minutes after that. Once IVT is up to 64'C I have all cells set to Stoich. I have a theory it can be used to help hot starts as well though.

{B0146}: This is used to fine tune the commanded fueling, for engine load and IVT. Again, it's only a commanded table, it's not used to "correct" a BEN difference when cold. I use this to add fuel when cold, and the load varies. Sometimes an engine will want more fuel when idling cold than when driving, so you can you this table to add more fuel in the idle cells, less when cruising. Once the engine approaches normal temps, all cells should be set to "1"

Remember that for both of these tables, they only take effect when the NB O2 sensors are not used. If you have STFT data occurring, these tables are not used at all.


Simon.

Edit: I should have commented on the trim issue....

{B1501} & {B1502} Set the enabling of full CL mode. These settings will control when the STFT's become active.
{B1503} & {B1504} Set the enabling of O2 Ready. These settings will control when the LTFT's become active.

In the stock calibrations, the second two table enable the LTFT's well before the first two tables enable CL mode. So you end up with LTFT's being applied with no O2 correction. I set these table to be the same ( {B1501} = {B1503} & {B1502} = {B1504} ) so all trims occur at the same time. Actually, to be truthful, I don't run LTFT's in my car at all. When I did run them, I set the tables to be equal.

[hymey]

I was waiting for Simon to reply :) The IVT tables should be used more so for cold start and can be used for lean start up issues which occur when going mafless on hot start. It is the best way to go about adding more fuel cold. It is just a multiplier of the vve or maf scale. And IVT will equal ECT until full running temp there after IVT will increase gradually over time until it roughly doubles ECT. You don't want your O2s coming on cold not until around 60 degrees.

cheers

[The Alchemist]

I was waiting for Simon to reply :) The IVT tables should be used more so for cold start and can be used for lean start up issues which occur when going mafless on hot start. It is the best way to go about adding more fuel cold. It is just a multiplier of the vve or maf scale. And IVT will equal ECT until full running temp there after IVT will increase gradually over time until it roughly doubles ECT. You don't want your O2s coming on cold not until around 60 degrees.

cheers

So in my case, the o2's were working from very cold at the factory temp setting B1502/04 is -40 and the runtime 10secs, once I see STFT activity these tables do sweet nothing! I will raise the temp settings to 60degC as you have suggested.
mmmmm
SOooooooo why was the commanded 14.68 yet the measured AFR was slightly lean at 15.2 when I was free revving at 2000rpm (was measuring at the tail pipe with reversion) then at 14:16.33 in my log the STFT suddenly changed from +10s to -3's when the ECT crossed over 80degC and the actual AFR changed to? What suddenly changes at 80degC to cause this?
AND when you reach 60degC and the STFT's are working is there no ECT enrichment table as such to adjust, its all just done by the VVT and STFT's???

BTW that idle stuff was awesume thanks got this car idling with zero swing sounding almost stock lolol !!!!! Couldn't believe the difference!
9258

[hymey]

So in my case, the o2's were working from very cold at the factory temp setting B1502/04 is -40 and the runtime 10secs, once I see STFT activity these tables do sweet nothing! I will raise the temp settings to 60degC as you have suggested.
mmmmm
SOooooooo why was the commanded 14.68 yet the measured AFR was slightly lean at 15.2 when I was free revving at 2000rpm (was measuring at the tail pipe with reversion) then at 14:16.33 in my log the STFT suddenly changed from +10s to -3's when the ECT crossed over 80degC and the actual AFR changed to? What suddenly changes at 80degC to cause this?
AND when you reach 60degC and the STFT's are working is there no ECT enrichment table as such to adjust, its all just done by the VVT and STFT's???

BTW that idle stuff was awesume thanks got this car idling with zero swing sounding almost stock lolol !!!!! Couldn't believe the difference!

Set them to 60 degrees C, the stft changes rapidly by the sounds of it, I will look at the log tonight, But the open loop tables are the only tables that have an effect on commanded afr, the engine will want more fuel cold aswell. Once the ects are hot and oil temps right up the IVT should be around 160 degrees and afrs will stabilise at this time IATs will have increased aswell from heatsoak in the manifold/blower. Also commanded idle rpm and TP%, idle vacuum changes can all alter afr suddenly if it drops to a different cell in the vve. Especially with the vve where individual cells cannot be changed so easily without affecting other areas. The IVT table multiplier changes commanded afr, If the afr changes by 13% and the commanded afr is still 14.68:1 it is most likely IAT and vve related, open loop alterations will show a difference in commanded afr.

I'm glad the idle instructions worked out for you, The e38 really eats the early pcm for controlling big cams once you get the hang of it. Once you nail min idle air,(which is basically desired airflow) you can raise max idle air back to factory values. min idle air is very sensitive and the easiest way to get it right is how I outlined it, by getting max idle area to the correct value, then lowering min idle air gradually until you can see the throttle blade trimming slightly when the throttle closes. 1 g/s to far and the trimming will be overactive and overcompensating, in which the first thing people do is start to make proportion and integral correction less aggressive, which does not need to happen. If you sneak up on min idle air by dropping it gradually you can get it spot on and the trims will only move plus or - 0.4%. Say if its idling at 18.0% it may go 17.6% on decel and recover idle with 18.4% before settling to 18.0% with 100% stock proportion and integral values. In which case I am very happy with as only the critical tables are altered. Once this outcome is reached see how the car feels to drive and work on getting coast down timing and idle timing correction right. After a bit of driving the idle gets even better as you may of noticed the e38 can really trim nicely and accurately if min idle air is right. The next morning I add 0.08 to max idle air and make sure I have enoguh air cold. If the engine is lagging behind commanded rpm and timing is high I basically keep bumping max idle air until the idle timing is around 15 degrees. I have found they cold start and drive cold a lot better by using more air rather then timing to get them starting and driving smoothly. I also suggest zeroing out cold noise reduction timing. This creates a lot of problems with a cammed car. The factory os adds timing cold in ect correction and then removes it in cold noise reduction? I just zero out both and run same timing cold to hot, I found it is the easiest way to do it.

[The Alchemist]

added screenshot for you to my last post
RPM Vacuum, TPS are all constant when this happens, the only thing I could see that changed was engine temp rolled over 80degC which could be completely unrelated anyways :) seems like a huge swing in trims when the commanded remains unchanged AT 14.68:1

<<For those reading thru this post and my ramblings the problem was that LTFT stored in the E38 were affecting logged AFR's even when in full open loop and during a cold start as well!. Morale of the story hit the fuel trim reset button under Bi-rectional control before commencing any VVT tuning in open loop>>

[swingtan]

As I've said before, if you work on an E38, you MUST log IVT. It can tell a different story to what ECT says....

As you would guess, there is a change in the engine efficiency that is causing the resultant change in trims. Assuming a cold start, the 80'C ECT probably relates to about 120' IVT. At this point, Dynamics are usually in a transition state between cold and hot running. I've found that dynamics can have an effect on fueling even when the airflow remains fairly constant, especially in cold start situations ( at least I think that's what it is.... )

Many would know that when going SD on the E38, you seem to end up with a very, very lean cold start. You can "fudge" the AFR's by commanding very rich when cold, or you can mess with dynamics to help reduce the lean condition. those that have looked in to this would know of an aprox. 8 second window after first start. I'm pretty sure this is dynamics related. If you want to rule out dynamics, you could try a cold start and disable all wall wetting in the tune. I might try this just to see what happens....

Simon

[hymey]

Yeah they are sensitive, without looking at the tune its hard to tell as you most likely have dynamics stock. I just finished an e38 then just by changing from dual 2.5inch to dual 3 inch system caused the entire vve to go out of whack also creating a very lean condition at start up at all ects. I would log IVT aswell. You have a blower on to which can change things. With the MAF on all these problems go away and when there setup correct there is hardly any difference in power anyway.

[swingtan]

I did a test today re: dynamics and the lean start condition..... They make little difference :P I turned off wall wetting all together and the AFR's were pretty much the same as when they were turned on ( for the initial 10 second start cycle ). They certainly made a difference when I attempted to move though.....

[gmh308]

One area worth looking at now that Ross & Paul have added them in are the airflow VE Compensation factors. These do influence the VE on a zone by zone basis to optimise mixture control on a dynamic basis related to MAP, TPS, related deltas/nearby history of both, and I think (maybe Ross could confirm...) Air Per Cyl. Not necessarily straightforward, but they do influence transient conditions and definately play a role in initial start up and "tip in" response. :)

[The Alchemist]

see attached log:
doing some tuning today on said vehicle and noticed that after reflashing and starting engine the STFT's stay high at 8 to 10% for a minute or so then do this transition down to -3%, once it does this I can start tuning etc etc see 18:46:39 expand to 18:47:08 and you will see this transition occur. It does it every time after a new start. everything stays constant while it does this AND it appears the AFR sits around 15.6:1 then transitions to a nice 14.36:1 when this happens. Car is in MAFLESS mode at the moment doing VVT.
Any ideas fellas?

Mike

[swingtan]

Are you running stock NB sensors or are you running a NB sim off the Autronic? The Autronic looks to be giving bad data and if you're running a NB sim based of it it could be causing issues. It's a bit difficult to see what is going on as the WB signal doesn't give a good view. It'd be better if you could confirm the actual exhaust ARF to see if the trims are actually doing the right thing.

Are you saying that the AFR's during the first 1:47 are sitting around 15.6:1 ? How are you checking this? If this os correct, then the trims are not doing what they should be doing, keeping the AFR's at stoich. If this is the case, it's very strange....

If I assume that the trims are working correctly, then you need to look at IVT. Note that the trim transition occurs right at 120'C, I exclude all data under 130'C when doing normal fueling corrections, as under this value the fueling becomes erratic as the engine warms up. It's possible that dynamics are influencing the fueling as in many E38 tunes, there is a change at about 120'C IVT in the evaporation tables. There is also a change between 40 and 60 kPA MAP, which seems to tie in with where you are dropping in and out of gear in the log. I'd be very interested to see what this did if you put the MAF back on, as I think you'll find the dynamics would behave better.

To fix you exact issue though, I'd probably try adjusting B2014, increasing the values below 120'C by maybe as much as 10% down to 72'C. The issue is that the E38 bases much of it's fueling on IVT, not as much on ECT. But at hot start, IVT=ECT, which is well under normal operating temp.

Simon.

[The Alchemist]

Hi there, did another cold start with 1 of the twin tail pipes blocked with a piece of wood :)
got great AFR readings this time for you to see. The NB o2's are the factory ones being logged and the WB in an Autronic unit on the dyno.
As you can see the AFRS are indeed constant during this transition yet the NB o2's show a 13% swing.
Thanks for the advice. Will look at B2014 for the next cold start tomorrow and during hot starts today.
Cheers,
Mike

[swingtan]

Hang on..... what are the LTFT's doing during this time ?

[The Alchemist]

turned off

[swingtan]

OK, was just checking. Thought they may have been involved.....

Post the tune so I can compare some settings.

[The Alchemist]

Heres a full cold start done today.
You can see the transition occur at 80deg C but this may not be the only thing that determines when this happens because it does that same thing on a HOT start at say 90deg C but only takes between 30sec and 1min 30sec after starting also at varying Intake Valve temps which is strange.
Also worth noting is that the trims go from +8% down to -3% with everything else constant so something must be "removing" fuel from the base fuel calculation while it is in closed loop ie a multiplier of some sort that then turns off at some predetermined setting.

This time I also logged actual O2 voltage and they appear not to be switching very well although they improve once you run the car under a bit of load at 2000rpm or so.
Can you PM your email and I will email the tune.
thanks,
Mike
9320

[The Alchemist]

Today I did a full open loop cold start AND logged pulse width this time, interestingly it seems to jump 0.5ms over a certain load/pulsewidth/whatever and jumps back again when you lower the throttle slightly. The VVT mapping is smooth here with no steep transitions at all.
This may have been the problem I have been chasing, should have done an open loop cold start ages ago !!! :hihi:
Of course this translates into very lean once warmed up over 80deg and IVT multipier down to "1" and then just right at 14.2:1 when it jumps up the 0.5ms.
Any ideas what is causing this...The injectors are FAST 65lbs ones and I have only reset the flow base setting and not touched anything else...(I know I know I'm meant do but can't find any data for them).
I have stepped the pulse width scales so I could see both of them...
thanks,
Mike

[The Alchemist]

on topic with idle settings I have found this works well for me, engine has a mild cam 225/230 591lift and a supercharger:
b1651 1.02
b1652 1.06 (hot only) during setting up not enough for a cold start
min idle airflow in park neutral at 800rpm around 9.3g/s and ingear around 9g/s

following your other suggestions for the integral/proportional stuff seemed to work well and relaxing the spark idle control.
average readings were as follows:

idle neutral 800rpm > SAE.TP 18.8% sspark 17deg average
in gear 800rpm > SAE.TP 18.4% spark 21 deg average.

what I could not seem to do was go open loop by maxing out minimum idle air to 63g/s and zeroing out the correction pids b1843/1845 as per this thread.
When I did this it didn't matter what I commanded in b1651 (I went from 0.5 to 3) all I got was a SAE.TP of 22% flatline and a high idle of about 1200rpm???
What have I done wrong?
Was adjusting b1651 when I shud have been adjusting B1652 stationery :)
worked at treat, just got to do a cold start now and tweak 51/52 to reach target idle and we're done. thanks Hymey and Swingtan !
Cheers,
Mike

[swingtan]

Ahh, yes.....
This is another one of those times when the descriptions for the tables don;t seem to match real life. It's not EFILives fault as I believe that descriptions are taken directly from the GM documented specs.

Think of these as follows...

{B1651}Max Commanded Idle Area - Not Stationary : That's right, this table will limit the maximum amount of idle control air when the car is not in "stationary idle mode" as defined in {B1817} and {B1818}. This is a % setting for throttle opening and may come under the old "TPS logarithmic" function. It has more of an effect at cold idle, where you command more air than normal.

{B1652}Max Commanded Idle Area - Stationary : This is the maximum amount of idle air when in stationary idle mode ( again {B1817} and {B1818} ). The description of "preventing vehicle creeping forward when the brake is pressed" is correct, but it it basically just plain old idle control.

To make it seem more "logical" use {B1652} as the primary idle control limiter. Normally you wouldn't think of having different tables for moving idle control, so it's easier to start with the second table. Also remember that it's simply an upper limit to the air control tables. Once you have controlled the idle here, moving idle control should not need a lot of adjustment. The one exception is if you get light throttle, low speed surge. The E38 seems to get a bit confused ( it's more likely me getting confused.... ) and tries to adjust the airflow when moving slowly. I'm assuming that the throttle position is not enough to exit "idle mode" and the ECM wants to try and control the engine speed. As Hymey has said, because the minimum control amount is quite large, you get surge when the correction amount as a large proportion of the current throttle opening. Setting {1651} to a lower figure than stock simply tells the ECM to give up on moving idle corrections at a lower throttle %.

To give an example, I have..

{B1651} = 0.75
{B1652} = 2.00

If you set {B1651} too low, it will stall when cold, and just idling along. I've had mine at the point where the idle speed will change as the vehicle speed transitions the settings in {B1817} and {B1818}.

Finally, remember that EFILive will not clear any learned settings in the ECM for the E38. You have to do this yourself with an ECM reset. Also, the Idle proportional step size may be too great for a cammed car. I've mentioned before that the engine will want to surge too some degree. All engines do it, even stock they do it, you just don't notice it unless you log the data and look for it. Trying to correct the "surge" can simply end with over correction surge, which is what I think most people end up with. With my idle proportional settings {B1845}, I have "0" in the normal idle control for the +/- 64RPM cells, then corrections ramp up past those limits. This limits the amount of "drift over time" that idle correction can cause. The engine idles at 700RPM +/- 50RPM normally, it's smooth with a 220/224@114 cam so why try and correct ? That's my thinking anyway, the same thing goes with the spark timing control. Too much too soon simply leads to over correction.

Last tip on finding airflow..... ( I may have already said this as well ). I log commanded spark, and average it over a period of time in ScanTool ( trying to eliminate where fans and aircon might be on ). If the averaged value is over the tune commanded idle spark, then I add more base air, if the average is under the tune settings, I reduce idle air. Once it's spot on, I add some more base air to help with stability and then use the correction tables to keep it in line. The main tables are the spark correction ones.

Simon.

[The Alchemist]

Oh My God!
that explains a lot...a subtle but very important clarification lolol
thanks heaps, I could probably lower B1651 now knowing what it actually does :) most of my idle testing was done stationery u see and I've been altering the wrong settings
Mike

[joecar]

Very interesting, thanks :cheers:

[hymey]

Yeah this is the beauty of the e38 ecm, cars with overlap camshafts of around ten degrees at 50, bugger all really but where most people don't want to go with daily drivers.

B1651 is definately for when the car is moving, but more importantly I have found that B1652 is basically stationary idle and even on coast down the TP% will find themselves at where they are when vehicle stationary, When the throttle is tipped in, pedal position percentage plus B1651 is total throttle percentage. So what Simon explains is definately correct.

A few weeks back I tuned a VE with a large cam, basically I did the following.

Drilled a 7mm hole in TB.

Zeroed out the integral and proportion tables and set min idle air to 63 g/s.

Set B1651 and B1652 to 1.10 and tuned as previous procedures to obtain desired TP% and idle timing, then reduced min idle air(with factory values populated in integral and proportional tables) until I started to see the throttle trim at idle. Then raised the value by .5 of a second( just to make sure I was bang on) and created a slight upward taper in the table.

The max idle area I achieved was 1.08, So set B1651 and 52 to 1.80, this then allows enough room for the car to have plenty of air cold start.

The car surged badly from the overlap. The trick here is to reduce B1651 to 0.15 below what was the correct max idle air in testing. So I ended up with .93(1.08-0.15) in B1651 and in B1652 I used 1.8, please take note that this exceeds the hard limit in most e38 pcms anyway.

The car then would drive much smoother on the throttle, ie around roundabouts there was zero surging say whereas before at 2% pedal position I would get bad surging now it was eliminated as it was building on the B1651 limit, but as I got off the gas the coast down idle percentages would raise back up, So it took no effort to take off from stand still etc.

Bare in mind this car was tuned in full open loop SD, running lower values in B1651 kind of works like a d port ex port in the way it reduces reversion, and I must say the e38 does it better then any other LSx pcm to date hands down. This car cruises at low 15 afrs at 100 km/h in 6th gear and puts around like a stock cam and yet has near 20 deg of overlap!

Again I was able to achieve this combined using, open loop speed density, working on dynamics and disabling power enrichment using the open loop fuel multiplier, After a lot of stuffing about I have also eliminated the lean spike issues on gear changes entirely by going away from PE and using STFTs to using more a LS1-cos3 approach.

For start up(cranking idle air-B1832), simply add your min idle airflow values across the board. When tuning fast to achieve a goal I found that if required idle airflow is 8g/s I add 8g/s everywhere and normally just massage it slightly here and there, it doesnt have to be fancy, infact if you seen some of my tables you would be shocked how bland but effective they are.

Cold start, As long as the above procedures are in place, I set...

B0141 through to B0144 all to 1.00 everywhere,

B0146 is populated to make fueling richer cold, Aim for 13:1 cold up to around 60 degs IVT, then lean off to 13.5 too 100 degrees before going to 1.00 above 100 IVT which will allow some enrichment on hot starts which is important.

So 1.15 to 60 then 1.10 ish to 100 IVT some smoothing there, your done.

I never add timing on cold start, it is not required, just airflow.

B5116 on a cammed car is a no no, set these to 0, that is all thats required for a largish cam to make them drive cold, optimal timing (same as hot) and remove the cold noise reduction values and there fine.

Again, I'm no good at tutorials, I am as clear as a Mathematics uni lecturer lol, You have to request a full tut by Swingy lol.

Also most of my testing is done in speed density, I have done a lot of MAF cars too,

Setting up B1651 really helps MAF cars are they are much more sensitive to reversion with large cams.

Normally at idle hz values, I will set the values the same across 5 or so cells, say from 3500 to 4500 odd I will add a fixed value of say 14.8 g/s as an example.

This does wonders for idle, As I have in the past set the idle parameters in a sensitive cammed car and it ran fine, I then went back and changed idle hz values and it started hunting, not from extra fuel but the TB started trim severely. It appears altering the g/s values in the MAF table also has an effect on the g/s values in min idle airflow.

I then decided to lock the idle airflow out get the afrs(g/s settings in MAF table) where I wanted them set them at a fixed value of where the hz will oscillate at idle, and then went from there. This was an experience for me I tell you lol.

Light loads at say 40 kpa I run around 14.0:1 afr around 50-60 I go low to mid 14s with cams sometimes 15s above 3000rpm I never go leaner then 13.0.

Getting B1651 right helps a lot with MAF tunes, then on slight throttle movements I look at the MAF oscillating and also keep the values the same in those cells as rpm increases I just ensure there is a smooth transition between cells. MAF tuned e38s with correct vves are magic, but in my belief done right is more work, Normally I tune speed density unless the customer requests. I have had cars have the afrs move over time with MAF cars whereas SD tuned cars never move. In a situation where a car is heat soaked and ramped on the dyno, the afrs will be more consistent with the MAF and mafless can move a little from heat soak, This is where the MAF shines. When changing altitude a MAF tuned car will vary afrs a lot more then SD car, and overall as said previously, I tuned two HSV's same owner similiar mods similiar kms before and after, 2 years later the SD car has a rock solid afr line, The MAF car did run a fair bit leaner I had to clean the MAF and retune. I presume it may have something to do with the total amount of airflow that is drawn into the engine has changed over time. I write about this as there is overall really less work in the SD tune to set up including idle and drivability of a big cammed e38 powered car. But having said that excellent results are obtainable with both.


This was just a quick update as a part of my blog, and again thank Simon for his relentless work also on e38s. Most tuners don't realise the work he has put into it. Above all dont make radical changes to compensate from errors elsewhere, Start from scratch keep it simple and keep it as basic and bland as possible. I just don't think there is enough info out there on e38 pcm tuning and believe me I could right a book on it this is just the icing on the cake.

Cheers

Joel

[hymey]

on topic with idle settings I have found this works well for me, engine has a mild cam 225/230 591lift and a supercharger:
b1651 1.8
b1652 2.5
min idle airflow in park neutral at 800rpm around 6.8g/s and ingear around 8g/s

following your other suggestions for the integral/proportional stuff seemed to work well and relaxing the spark idle control.
average readings were as follows:

idle neutral 800rpm > SAE.TP 18.4% GM.ETCTP 9.3% MAF 11.96/s calc MAF 10.63g/s spark 20.5deg average
in gear 800rpm > SAE.TP 21.8% GM.ETCTP 13.5% MAF 15.57g/s Calc MAF 12.82g/s spark 22.5deg average.

what I could not seem to do was go open loop by maxing out minimum idle air to 63g/s and zeroing out the correction pids b1843/1845 as per this thread.
When I did this it didn't matter what I commanded in b1651 (I went from 0.5 to 3) all I got was a SAE.TP of 22% flatline and a high idle of about 1200rpm???
What have I done wrong?
I ended up finding the sweet spot by putting min air really low at 4g/s and B1651 at about "2" and slowly narrowing the gap until the idle swings stopped.
Cheers,
Mike

Mike I wish I was over there with ya having a fiddle with it. B1652 is definately the parameter that will prevent it from going to the hard limit percentage.

The reason why you may of been having issues with the min idle air is because the MAF g/s values definately play a role and are linked to min idle airflow. I get the idle afrs right before tuning and flat line them. across 4 or so cells so I get consistent airflow readings at idle. As long as B1652 set at say 1.00 and min idle air is 63g/s it will definately stop it from going to 22%. The MAF cars can be tricky at idle. Once I go blower or big cam the MAF goes and it eliminates the issues you get with it from idle tuning. I should have mentioned this earlier, just another glitch.

Once you get min idle air right, and you no what B1652 value you used to get reduce that value by .15 and place it in B1651 and then set B1652 to around 2.00, 2.00 and around 0.90 is around normal, you can experiment going down to 0.7 as Simon has done 1 car I have 0.5 in there.

Hope this helps

Joel

[hymey]

I should also mention that the factory style efi manifold does play part in some weird idle tuning, Ie idle timing corrections and airflow corrections are largely related to the style of the factory bunch of bananas manifold.

A single plain traditional manifold with equal runners not going into a large plenum area makes a massive difference. I run idle timing locked out and airflow locked out hot and cold, I just add more choke at start up it fires up and runs to commanded rpm, Also drives smoother then the factory manifold.

From my testing its not only cold moving parts and oil that create the need for more air at start and also power steering air con and alternator load variances that require the need for timing adjustment while idling. It has appeared to me the design of the manifold with some cylinders readily getting more air at idle then others that creates the need for a complex idle control system.

My new setup, Some nice ported L92 heads....GMPP manifold, 12.2:1 compression, E85.

Camshaft...248-254 on 106 LSA, from testing the efi 112-116 LSA cams aren't working with this manifold going to just a 110 LSA showed a massive improvement in torque, So I am going to 106LSA to make the most of the manifold a traditional carb manifold grind, and with the manifold having better idle manners it should work out just fine.

Cheers

[hymey]

http://www.youtube.com/watch?v=-Ye_IGa3i2c

Here is an example of a customer's vehicle. It is a VZ SS sedan with a 6L L76, 4-2-1 pacemaker headers and a dual 2.5 inch exhaust. I fitted a 22x 22x 112 LSA camshaft with overlap exceeding 0 degrees. The first owner wanted it choppy, the new owner purchased the vehicle fitted a 4000rpm stall and 3.9 diff gears. I retuned the idle and it reels off 11 sec passes easily at full weight. Here you can see car idling at 800 rpm and 40 kpa both in drive and neutral, including loading the car in drive and letting it return to idle using only 15 degrees of idle timing with very little spark correction. I also have a 6mm hole in the throttle blade and it uses entirely stock proportional and integral correction tables. The car is tuned in full open loop and speed density. Has only been road tuned for drivability and track tuned for top end. I love this car as it idles stock and has no troubles hosing the likes of a boosted typhoon on the street as its so snappy, I have never achieved such a smooth idle in earlier LS cars using the same camshaft. Gives an idea of what can be achieved.

cheers

[joecar]

Wow, good job mate :cheers:

[gmh308]

Yes...what Joecar said. Great job there hymey. You are leading the way there delving into E38 tuning with cams and idling with Mr Swingtan. Wow that's smooth as !!!!! ;)

[ringram]

Well I think we are missing a couple of tables still :)
Like an ECT modifier for adding g/sec for cold starts.
Min airflow is fine once warmed up. But not for cold starts.
Sure there is ECT "Correction" multipliers. But nothing for base idle airflow addition vs ECT.

The reason I mention this is because my 440 cube lump doesnt like cold starts. It fires and dies immediately no matter what min idle airflow I use.
Im going to have to join the rest of you lot and drill the blade. Im sure if there was an ECT adder to base airflow then that would not be necessary.

Cranking idle air is also fine for the initial firing, its when it blends into idle airflow at like 3*C it just dies. Ramping correction multiplier up doesnt do anything useful either.
At around 40*C ECT she settles down and idles much better.

Anyway, the drill is coming out this week hopefully that will give me the base airflow g/sec I need to prevent the cold start stalls.

[gmh308]

Well I think we are missing a couple of tables still :)
Like an ECT modifier for adding g/sec for cold starts.
Min airflow is fine once warmed up. But not for cold starts.
Sure there is ECT "Correction" multipliers. But nothing for base idle airflow addition vs ECT.

The reason I mention this is because my 440 cube lump doesnt like cold starts. It fires and dies immediately no matter what min idle airflow I use.
Im going to have to join the rest of you lot and drill the blade. Im sure if there was an ECT adder to base airflow then that would not be necessary.

Cranking idle air is also fine for the initial firing, its when it blends into idle airflow at like 3*C it just dies. Ramping correction multiplier up doesnt do anything useful either.
At around 40*C ECT she settles down and idles much better.

Anyway, the drill is coming out this week hopefully that will give me the base airflow g/sec I need to prevent the cold start stalls.

Tried reducing the cranking VE mult table ?

[hymey]

Well I think we are missing a couple of tables still :)
Like an ECT modifier for adding g/sec for cold starts.
Min airflow is fine once warmed up. But not for cold starts.
Sure there is ECT "Correction" multipliers. But nothing for base idle airflow addition vs ECT.

The reason I mention this is because my 440 cube lump doesnt like cold starts. It fires and dies immediately no matter what min idle airflow I use.
Im going to have to join the rest of you lot and drill the blade. Im sure if there was an ECT adder to base airflow then that would not be necessary.

.

B1602 Richard. It's all there:) This is the multiplier to min idle air. So when it is warmed up it is fine. Take note earlier o/s gave 1.00 there when hot, later have 0.25. It's all been looked at mate and tested over and over.

The reason why it won't start cold is because the e38 is designed for a stock cammed engined not a cammed 440. You need to drill it to allow for a LOT more air cold. And after you drill it, it will need to be retuned at idle:)

So when you first replied to the thread a while ago and said it is not required, just add it in the tune, this is all good on paper, but it will not work for the reasons I have outlined over and over, hence why I originally told you it was important. Would have saved you a whole lot of heartache to follow instructions:) You need to drill 2 holes in yours maybe two 5 mill holes, 1 at the top and 1 at the bottom. B1602 x your final g/s value will max out min idle air so that it runs on B1652 at cold. If it rpm's low dont add timing add a bigger hole. Once you do this cranking idle air will be to high it will race off.! As cranking idle air will max out max idle area aswell just like min idle air does! ie at 12 g/s she is maxxed out hence why it won't fire right up.

Once it is enough air at cold( and believe me you will be better off with two small holes rather then one ten-but start with one first, then step up 1mm a time in the second to achieve your goal) you will find it may overshoot on cold start. Simply add your min idle air values to the cranking idle air table and test it. It will be close just need a slight raise at the most towards cold ect values.

Also Cranking VE can stay stock, I recommend don't touch tables that are not required and this is one of them.

I would also change cranking timing in yours to around 20 degrees cold and 12 hot. Big cammed stuff likes this, Again it is not a factory engine.

I am not writing this to send people backwards, It will solve your issues, just tuned another one last night with 240s cam and heads, idle done in ten minutes.

Let me know how you go champ,

Cheers mate

[The Alchemist]

yup '1" and a idle learn reset did it !!! yay :)
Also found my other little problem with the IPW jumping was "fixed' by a fuel learn reset too :)
I thought when you reflashed a E38 the fuel trims were reset automatically?????
I had the car in full open loop of course but obviously there was a long term trim still stored in the E38.
VVT sorted in 5 AFR sweeps on the dyno > wicked !
Question: why can't you "see" LTFT's stored in memory like you can in the LS1 ECU's?

[swingtan]

Well I think we are missing a couple of tables still :)
Like an ECT modifier for adding g/sec for cold starts.
Min airflow is fine once warmed up. But not for cold starts.
Sure there is ECT "Correction" multipliers. But nothing for base idle airflow addition vs ECT.

The reason I mention this is because my 440 cube lump doesnt like cold starts. It fires and dies immediately no matter what min idle airflow I use.
Im going to have to join the rest of you lot and drill the blade. Im sure if there was an ECT adder to base airflow then that would not be necessary.

Cranking idle air is also fine for the initial firing, its when it blends into idle airflow at like 3*C it just dies. Ramping correction multiplier up doesnt do anything useful either.
At around 40*C ECT she settles down and idles much better.

Anyway, the drill is coming out this week hopefully that will give me the base airflow g/sec I need to prevent the cold start stalls.

What you may also want to look at is....


{B1832} Cranking Idle Air: Sets the base airflow for cranking. If you find the engine starts better if you us a bit of throttle, then you want to increase the values in here.
{B1833} / {B1834} Cranking Air Mode Upper /Lower: Times when the ECM switches from cranking mode to general run mode. It's possible that in your case, the ECM is either staying in crank mode too long, or not long enough. I'm going to guess the first one.


I haven't drilled the blade in mine, but it's only got a small cam. I'd drill the blade if I had a spare one to play with though..... Maybe I'll just drill it anyway :p




yup '1" and a idle learn reset did it !!! yay :)
Also found my other little problem with the IPW jumping was "fixed' by a fuel learn reset too :)
I thought when you reflashed a E38 the fuel trims were reset automatically?????
I had the car in full open loop of course but obviously there was a long term trim still stored in the E38.
VVT sorted in 5 AFR sweeps on the dyno > wicked !
Question: why can't you "see" LTFT's stored in memory like you can in the LS1 ECU's?

Excellent work! I had a feeling that the LTFT's may still have been active, but not learning. The only way I've checked for LTFT's is to log them, or I just do an ECM reset to ensure they are gone. This also clears any learned idle control as well, which is a must when trying to get the idle right. It would be nice to have a "learned data reset" option in the V2 Tuning section..... nudge, nudge.....


Simon

[ringram]

Yeah maybe my cranking idle air is too large. I did wind it up quite a bit earlier on with the last cam (only 6* overlap). It fires up to 2000rpm and drops from there, perhaps if it was 1300rpm or so it wouldnt overshoot.
When warm it cranks, fires and idles pretty well. With only about 100-200rpm overshoot on the downside. (which a small hole might sort)

I read b1602 as a multiplier to the correction factors rather than a multiplier to min idle air.

Some more ideas to play with anyway :)

[hymey]

There are multipliers for correction factors, but not b1602, it is for min idle air. Try doubling its value. As a matter of interest does your car have 0.25 multiplier when hot? or 1.00. The earlier ones had 1.00 and later 0.25 hot and 0.5 cold. Now try changing this value to 1.00 and you will see it multiplying min idle air:) It will max out the TB for 13 seconds and then learn back.

[hymey]

I do the same as Simon, sometimes I flash e38's and they do not clear codes when they should so I manually clear them.

Latest issue, Turning cat protection enable to off does not seam to work on some os. The DTC is activated still on long drives, so I leave them enabled and raise the temp enable to 2000 degrees C.

Some weird things happen with e38s and reseting the ecm is the go. If the ecm has learned it self to idle at 8g/s and it needs to be 5 and you command 5g/s it will still try and idle at 8 etc.

Personally I have not had any LTFT issue's as I never use them, but it is a good idea to reset anyway.

Wait till you flash a car that has been tuned with HPT cos, even after a full reflash there are so many glitches!

[hymey]

I haven't drilled the blade in mine, but it's only got a small cam. I'd drill the blade if I had a spare one to play with though..... Maybe I'll just drill it anyway :p






Simon

Gday Simon,

You most likely won't need to as the L76 os gives you a higher limit.

Long time no hear bud , will have a chat to you when I see you on msn. Need to run some things over with u:)

Joel

[swingtan]

Yeah, it's been a while :P You've been a busy boy up there. As you say, there was change in {B1602} and as I don;t get a large number of cars to play with, I haven't looked at the differences a lot. In my tune, I go from 1.0 when hot, all the way to 1.8 when cold. This gives an additional 1.8x the min idle air when cold. I'm just in the middle of doing some screen shots to show a few other tricks for Idle tuning, because the e38 learns very fast and remembers for a long time.

Simon

[swingtan]

OK, here's a few more tips.....

attached are 2 images ( click for larger view ) showing the effects of too much idle air and too little idle air. Let's first look at too little...

http://farm5.static.flickr.com/4104/5165076029_ff2f9efbdc_z.jpg (http://www.flickr.com/photos/swingtan/5165076029/sizes/l/in/photostream/)

Commanded spark is 23'
Commanded idle air is 7gm/Sec

Note the logged airflow and spark for the entire idle section is fairly constant, but there is some instability shown in the MAP and RPM traces. The averages of all traces shows close to spot on the commanded values, though Idle airflow is up at 7.5gm/Sec, indicating that idle air control is adding air.

Now for comparison, too much idle air...

http://farm2.static.flickr.com/1337/5165076025_1d74195c3b_z.jpg (http://www.flickr.com/photos/swingtan/5165076025/sizes/l/in/photostream/)

The main difference here is that min idle air is set to 8.5gm/sec. You will quickly see the difference in the start of the idle data. Initially, the ECM is commanding too much airflow and to try and reduce the idle speed, is pulling timing. Airflow at the start is about 8.2gm/Sec, timing is down to 16' on average, try and reduce the idle speed. From the time the clutch was pressed in, it took about 18 seconds for the ECM to pull the airflow back to where the idle speed meets the commanded value. After this point, idle speed and spark average out to the commanded values. At this point, the logged airflow is averaging 6.7gm/Sec and the idle but both the idle speed and MAP traces are very stable.

The comparisons here are interesting....

When idle airflow is commanded low and the ECM learns up, the idle quality is worse than if the commanded air is high and the ECM learns down. This occurs even though the resultant airflow is lower when the commanded air flow is high. If the commanded airflow is set too high, the idle hangs for a little while till the ECM corrects the airflow. This can help if the engine tends to stall on "clutch in", but can be annoying by causing the idle to stay high for too long.

It's not a surprise that commanding a higher airflow at idle helps with stability, it's just that now we have some actual data to help understand what is going on. In this case, I'm going to set min idle air at about 8gm/Sec

Simon

[The Alchemist]

now that I've got the idle sorted and the VVT up to 100kpa sorted I'm getting a 2 bar MAP sensor for tomorrow as the factory VE MAP sensor maxs out at 120kpa....not 1.5bar like I've read in the forum sites.
Only one way to find these things out is to try it for yourself aye?
I guess the fact that its climbing out of the dyno in 4th at 2000rpm speaks volumes of what to expect tomorrow!

[ringram]

I do the same as Simon, sometimes I flash e38's and they do not clear codes when they should so I manually clear them.

Latest issue, Turning cat protection enable to off does not seam to work on some os. The DTC is activated still on long drives, so I leave them enabled and raise the temp enable to 2000 degrees C.

Some weird things happen with e38s and reseting the ecm is the go. If the ecm has learned it self to idle at 8g/s and it needs to be 5 and you command 5g/s it will still try and idle at 8 etc.

Personally I have not had any LTFT issue's as I never use them, but it is a good idea to reset anyway.

Wait till you flash a car that has been tuned with HPT cos, even after a full reflash there are so many glitches!

Ah, that might explain some weirdness I have been seeing! It appeared that nothing I did changed anything. Ill pull the fuse!

[ringram]

Ok, pulled the fuse still no good. This illustrates the issue exactly.

9440

You can see just at the selection line etcpos is at 20% 2 frames later its at 12% and spark hasnt changed. This is crank fire nicely, dropping to hard into normal spark.
Now g/sec is around the low 20g/sec range and drop to around 8g/sec when the throttle closes. My min idle air is 10.2g/sec.

I pulled the ECU fuse. But this is the issue. No matter whats in min idle air or the correction table after firing it drops too low. Ive messed with just about every table under the sun.

I know you guys want me to drill the throttle and Im at the point of doing that now to take care of the issue, because when its cold it dies. You have to hold the throttle down a while till it gets to around 40*C ECT before it will sort itself out. Eventually at temp we are still around 10g/sec and all is now well.

I need to ramp ETCTP down from the fireup 20% to the hot idle more gradually over time, but it wont do it no matter what. (Ok maybe if I drill the mother)

My correction table at the point above says 1.2x and even at 1.5x when colder so I should have around 13g/sec but I dont. I have used even higher numbers in the ect airflow correction table to no avail.
Any ideas accepted gratefully :)

[TuneMaster]

Post or PM me your tune file so i can take a look. I'll send it back with something for you to try.

[swingtan]

OK, try this to help iron out the Idle learning....
Repeating my self a bit, all engines have some amount of inherent "lope". I find that trying to correct that lope can lead to increased instability and idle problems. So I look for what I think is the "natural lope" and don't ( or only marginally ) correct for that. So....


{B1845}: Idle Proportional Step Size - This is like the "long term" idle adjustments ( though it comes into play fairly quickly ). For "Normal Idle" I have all cells from +64 and -64 set to "0" ( that includes the +64 and -54 cells ). This basically disables long term idle corrections when the idle is close to correct, leaving you only the Intergral, or instant idle corrections ( which are much smaller steps ).
{B1652}: Max Idle Area 2 - Or stationary idle, set at a fairly high value. My belief is that this value is related to the logarithmic throttle control function like the PE tables. So 2% here should relate to about 18% max throttle when logged with ETCTP. 2.5% herer should see around 21% to 22% at the throttle but you may need 3% to get to a real 26% throttle opening. Mine is currently set to 1.8%
{B1837}: Idle Integral Limit, Upper - This is the upper limit for the integral adjustments. These shouldn't need to be adjusted unless you find the Integral adjustments are running out of adjustment. I've set mine down to 1gm/Sec and not had issues, but it's a smaller engine and smaller cam.



Of course you may be hitting a hard limit as Hymey has mentioned. I've not seen that, but have not been as hands on with bigger cammed cars. Have you logged the cold start with a WB, going from pre-crank to start and the stall issue? I wonder if dynamics is coming in to play? If you send me a log and tune, I'll have a look.

Simon

[ringram]

9442

Current tune attached for general abuse ;)

[ringram]

As mentioned the main issue is the transition from cranking idle airflow into idle airflow

Its too fast and too sudden. airflow correction modifier vs ECT doesnt do anything. Im pretty sure its in the Corrections sub container for a reason.. being it multiplies the correction to airflow not the base airflow itself.

[swingtan]

OK, try this. I've dropped your cranking air a bit as I think it may have been too much and the ECM is attempting to correct and pulling too much air. I'm also tempted to redo all of your idle correction tables, but should probably see how this first effort goes. I've also played with the dynamics a little in the cold cells and tweaked the min idle airflow. I'd really like to see a log with the WB of a cold start though.

Simon.

9444

[Tre-Cool]

Just throwing this out there as I have had it happen on 2 different e38 car's. 06 & 09 model

Basically idle is perfect, but if you turn the car off and then go to start it again the car will not idle/fire correctly.

If you attempt to touch the throttle the car struggles to rev or it just dies out as if it's not firing.

I have spoken and sent the tune to Joel to look at and unfortunatly none of the changes made a difference, it's as if the car is looking for the maf on a restart.

If you leave the car off for a few minutes the car will fire straight up.

[ringram]

CLSD, MAF is plugged in but in fail mode.. Hmm maybe I should re-enable it to see if that has an effect.

SwingT Ill try your tune and let you know, thanks. I might have to log o2 mv in lieu of WB as I took it out a while back... its now UK winter, so probably wont get it back in for a while.

[ringram]

Hi mate, your attachment link doesnt work.
Ill drop cranking down a little more to see what happens there in the interim. Thanks for the extra tips.

[swingtan]

Try this then, not sure what happened....

9446

[swingtan]

Just throwing this out there as I have had it happen on 2 different e38 car's. 06 & 09 model

Basically idle is perfect, but if you turn the car off and then go to start it again the car will not idle/fire correctly.

If you attempt to touch the throttle the car struggles to rev or it just dies out as if it's not firing.

I have spoken and sent the tune to Joel to look at and unfortunatly none of the changes made a difference, it's as if the car is looking for the maf on a restart.

If you leave the car off for a few minutes the car will fire straight up.

I reckon that is dynamics. On a hot restart, the ECT is up, but the IVT is way down from where it should be for normal running. As usual, post a log and matching tune.

Simon

[Tre-Cool]

I would like to agree with you, but it played up badly today when we got it on the dyno. it wouldnt start for 30 minutes. with multiple changes to the tune.

i ended up reverting to a tune prior to the maf & etc limits as per normal before it would work again.

What i did find interesting though was when it was playing up i started logging it with the engine off, if i put the pedal to the floor there was a good 2 second delay before the scanner registered the tps change. then the same again when i lifted. even on small pedal movements there was a significant delay.

P.S the first car was a stock cam statesman with the maf removed. as soon as we plugged the maf back in it would work. 30 minutes later with the exact same tune it would run fine without the maf.

[swingtan]

PCM reset and ensure you wait 15 seconds after a flash? Both of these should clear any "in memory" issues with the tune. I've seen weird stuff happen if you try and short cut the 15 second wait, Idle spark control that gives up after a couple of seconds is a classic. Were you doing laptop logging? I'm guessing yes with the dyno and I've seen very slow response when laptop logging at times. Normally a reboot fixes it up though. Did you check the actual throttle blade to see if it was responding slow as well?

Personally, I feel that the stock tune commands too much fuel on hot start. I've leaned mine out to 14.5:1 and have no starting issues. I still think it's fuel related and the slow throttle was a Scantool / USB issue. I'd need to see a good log of the start up though to get an idea of what is going on.

Simon.

[ringram]

Ok 7mm hole drilled. Far too big. Now cant close throttle enough and I get a P0068, so weld is required :(
I think I tuned the DTC out with the ETC processing tables.
But from the initial results it seems it might help. Just a FYI start small unless you want a 1000+ rpm min idle.
Also idle hangs pretty badly. Probably can tune that out with the correction tables, but I need a smaller hole anyway... Ho hum..
Definitely some tables missing!

Update: If I had a cam big enough to warrant a 1000rpm idle then Id be set. Cold start worked well. Tuned out the DTC no problem by c0805 and c0806 tweaks.
Ive had to ramp up integral corrections by a shed load and drop all my other tables back to stock. Still too much air and idle still hangs but not as bad.
Anyway, I think Ill weld her up and bung a 5mm hole in there.

Hopefully one day Ross can find a few more idle control tables and avoid such a crude method ;)

[doubledip]

Start with 3mm or if cam big enough 4mm but that's all

[ringram]

Im with you on that now :)

[The Alchemist]

Ok, tuning going well with this supercharged Ute BUT.....have been trying to get dead cold start spot on..
Hot idle setting 51/52 set at 1.1 (18.8% TP) in "open loop" with 18deg average timing at 800rpm. I set minimum idle air to about 9.3g/s where the TP starts trimming > perfect!
Cold start another story!
Obviously you need more throttle cold so I started with the 0.08 extra as suggested by Hymey the next morning > starts and stalled immediately. tried 1.3 (20.4% TP) starts, just idles timing at 28deg (this seems to be a hard limit for timing at idle hot or cold? correct?) won't accept throttle or in gear load until its been idling for 30 sec or so.
Now...
Whats weird is that increasing 51/52 to 1.4, 1.5, 1.6, 1.8 with reflashing and an idle reset before starting the TP stays as 20.4% regardless and idle is OK at about 750rpm with timing at 28degs yet desired is 1000rpm dead cold . Why is this happening, surely as you increase 51/52 the idle TP% should increase. Once you get over 1.9 the TP is still 20.4% but you start to get a light idle surge or hunt for the first 60sec or so that decays away.
With idle learn do you need multiple cold starts over a few days for the tp% to actually learn upwards past 20.4%???
Any suggestions guys? Been mucking around with this over the past 5 days.
Mike

[ringram]

Same issues as me by the sounds. No matter what the table settings they are no good. Perhaps they do learn over time. But I ended up with a hole.. too big, to compensate.
I think there are tables missing. I need more air in the 440 with 18* overlap, but the only way I could get it was to drill. As mentioned above, start small and work up. You will find the etc will still trim and compensate, but no longer gets the same caps as you are adding air via the hole to the inbuilt limits. I suspect there are some settings missing. There could be a hard idle cap at 20.4% which we dont have access to for example.

[swingtan]

RE: Idle timing upper hard limits. It's what ever your "normal" timing table has in those cells.

IE, If the Hi/Low blend for {B5101} and {B5102} is 28', then the maximum idle timing will be 28'. If the blend is 26' then the max idle timing will be 26'. Raise the values in {B5010} and you raise the upper idle timing limit. It took me a while to work that one out......

Also, note {B1836} to {B1838} and {B1840} to {B1842} ( if your OS has all those... ) {B1651} and {B1652} are absolute limits in throttle % (using the logarithmic table I've posted elsewhere ). So 2% in these tables is about 18%-20% throttle when logged. The other tables are absolute correction limits in gm/Sec. In my OS, the stock settings will limit the amount of correction to 5gm/Sec, so these will limit the "dynamic" correction amounts. I still think the ECT correction should be enough to get the desired airflow though. At a cold idle of 1000RPM on mine, I have 15% throttle and just over 17gm/Sec of air flow. As for tables missing... I think there will always be "some" missing tables :p.

Simon.

[hymey]

Ok 7mm hole drilled. Far too big. Now cant close throttle enough and I get a P0068, so weld is required :(
I think I tuned the DTC out with the ETC processing tables.
But from the initial results it seems it might help. Just a FYI start small unless you want a 1000+ rpm min idle.
Also idle hangs pretty badly. Probably can tune that out with the correction tables, but I need a smaller hole anyway... Ho hum..
Definitely some tables missing!

Update: If I had a cam big enough to warrant a 1000rpm idle then Id be set. Cold start worked well. Tuned out the DTC no problem by c0805 and c0806 tweaks.
Ive had to ramp up integral corrections by a shed load and drop all my other tables back to stock. Still too much air and idle still hangs but not as bad.
Anyway, I think Ill weld her up and bung a 5mm hole in there.

Hopefully one day Ross can find a few more idle control tables and avoid such a crude method ;)

Hi Ringram, if you send me the tune I will fix your problem. I run 7mm holes with 224/228s in 6L.

Whatever you do don't weld the hole if P0068 table sets in it will make the idle hang by a mile. I will fix your tune in 5minutes if you send it through bud,

Leave the correction values stock until you get a decent idle. If your car is setting P0068 it will idle high. You will get rid of the limp mode by turning the MAF/MAP correlation test off. You have no MAF so no test required.

With SAE.TP you can drop all the way to 12% throttle in B1652. That is VERY low. You can get a stock cam idling with it.!

So u are making a simple mistake champ. Just send me the tune and I will get it idling. DOn't weld your blade you will warp it!

BTW my car has two holes in the TB!

[hymey]

Send it through I will fix.

For cranking the engine.

Set cranking timing to 18 degrees. Cranking idle air to whatever the g/sec value is in min idle airflow.

Set max -10 in cranking timing correction.

You have other stuff messed up in the tune I will get it happening for you sound like u are having some issues with it and changing to many things to compensate.

We are here to help!

[hymey]

Again simple fix. I see you tune now will sort it tonight. But again as a rule, cranking timing, cranking idle air to min idle air values and max -10 on overshoot is the key!

I have just completed a 6L with a custom cam on a 108LSA! Yes a lot of overlap. Works awesome. I has no surging issues like the 112 LSA's can sometimes get as the 108 lobe sep is pulling air through much faster.

Will post up tonight.

Joel

[The Alchemist]

[QUOTE=swingtan;133043]RE: Idle timing upper hard limits. It's what ever your "normal" timing table has in those cells.

IE, If the Hi/Low blend for {B5101} and {B5102} is 28', then the maximum idle timing will be 28'. If the blend is 26' then the max idle timing will be 26'. Raise the values in {B5010} and you raise the upper idle timing limit. It took me a while to work that one out......

Oh FFS you are joking !!!! really....I tried this and you are correct, timing trim now goes up to 32 if "32" is entered in this table in idle zones. I had 28 in there hence my "hard" limit. This helped cold starts, thx.
Next question is, if the high/low tables set the upper hard limit at idle what does the ECU do/need with the BASE IDLE timing table? Is this just for initial desired timing?
Mike

[swingtan]

I tried this and you are correct, timing trim now goes up to 32 if "32" is entered in this table in idle zones. I had 28 in there hence my "hard" limit. This helped cold starts, thx.
Next question is, if the high/low tables set the upper hard limit at idle what does the ECU do/need with the BASE IDLE timing table? Is this just for initial desired timing?
Mike

As I said... it took me a while to work that one out. It's very strange indeed but helps a lot once you know about it.

I think the base idle tables are there to set the timing "goal" for stationary idle. Why it allows more when moving ( or non idle mode timing ) I'm not too sure about. Need to think some more on that one.

Simon.

[hymey]

Hey Swingy thanks for that tip mate. I normally just use airflow. Though this will help cold starts, It gives one the option to lock out max idle area with no correction. Again cranking idle air needs to be maxxed out aswell. Cranking timing set it to 18 degrees Hot, possibly 30 cold. When hot limit flare up timing control to -10. Experiment with the multiplier cold. Excellent work mate. Appreciate that.

To make things so much easier for the big cammed brigade. There is a trick I do with HPT. (sorry efi guys lol) EFI live does not have the tables but I am going to request them.

HPT has max idle area 1 and 2. I actually requested those to be added. But they also have a table called from memory. Max idle fail. And Min idle fail. Now this is something I do with big cams and it is very simple.

Max idle fail is 60 (this is an upper limit) and Min idle fail is 5( lower hard limit!)

Efilive does not have these values at present,

Now for hot idle running I change the ect airflow multplier to 0.01 and set min idle are to 63 still. So I end up with 0.63g/s enough to pull on the lower limit which is 5. I drill s 7mm hole and set the lower value to around 25 to 45 pending on idle setup. I simply find best idle timing(Easy to do). I play around with basi idle spark and correction to get correct idle return with no hunting or popping and hanging.

I turn the A/C on. If the idle drops to much I got into around the -128 rpm cell and set it high to like 20 degrees, maybe even 25 degrees until I get the idle rpm I desire with a/c on full lock lights on etc.

Then I focus on coast down tables, same thing but I command a higher amount of spark there so the idle does not dip below 1000rpm.

Cold start, now this is the trick we only really need heaps of air cold start to get the car going and holding say 1000rpm for a few minutes until the temp gauge goes up.

In the ECT multiplier I set it to the upper limit. So I place 1.00 in the multiplier till 68 degrees C. From 70 deg onwards we can go on the lower limit and you will not notice the transition if hot idle is setup correctly with the lower timing correction placed as previously outlined.

Again idle timing 18 degrees this time across the board. Flare control limited to -10 degrees max. And cranking idle air. Max the values out up to 68 degrees C, Set to 63 g/s. Remember cranking idle air is also limited to hard limits!

You will not notice the transition at all from high to low if the hole in the TB is correct and the limits and timing are correct.

After 68 degrees set the hole table to 0 g/s. This will pull it to the lower limit and stop the e38 getting confused on start up.

Remember 18 degrees cranking spark. limit flare control to -10 degrees and it will start and idle better then ever.

Once the guys(please) add them in. I will set it up and show you.

Cheers

[hymey]

Simon once the vehicle is rolling it transfer to "coast down spark" the threshold in my car is 2km/h so over that once I am rolling I can command different amounts of "rolling idle timing". Maybe you already know this and I misunderstood your post.

[swingtan]

Yes, coast down spark if the throttle is closed and the desired RPM is below the current RPM....

[The Alchemist]

heres my log of a full cold start and screen shot of startup and 20sec plus.
Finally, changing to 18deg cranking timing increasing the cranking idle air right up, max -10 on the rpm flare as per Hymey instructions it burst into life like the true animal it is instead of sounding apologetic then surging like a bitch lol :) This made the biggest difference I think to the actual idle quality immediately after starting.
Also allowing idle spark trim to hit 34deg also stabilised the idle > thanks Swingtan.

My TP% was still only 20.4% even though I increased 51/52 up as high as 2.7 , I also put "1"s in the airflow multiplier up to 68deg and made no difference to TP% yet in open loop with the min air flow maxxed to 63g/s I can command the hard limit of 22% easily. So I can only achieve 860rpm even though my desired is 950-1000 at startup but its steady as a rock now! I will check again in the morning without resitting idle learn and see if it commands more
Finally a question: immediately after startup the AFR sits as 14.4:1 for 15sec every time when cold then steps down to 13.5:1. Changing IVT multiplier only causes the 13.5:1 to dip into the 12's and makes no change to the 14.4:1 section. Is there an afterstart enrichment setting somewhere or is this altered by changing cranking fuel settings?
Any ideas? I just think it would be better a bit richer as the idle doesn't truely stablise until it richens up to 13.5:1.
Cheers,
Mike :grin::grin::grin::grin:

[hymey]

Excellent work! We are getting progress. You maybe be able to drill a slightly larger hole to get more air cold but then you have to redo all the idle tables! I would be happy with what you have it is stable.

Joel

[joecar]

Good job :cheers: excellent thread.

[swingtan]

My TP% was still only 20.4% even though I increased 51/52 up as high as 2.7 , I also put "1"s in the airflow multiplier up to 68deg and made no difference to TP% yet in open loop with the min air flow maxxed to 63g/s I can command the hard limit of 22% easily. So I can only achieve 860rpm even though my desired is 950-1000 at startup but its steady as a rock now! I will check again in the morning without resitting idle learn and see if it commands more
Finally a question: immediately after startup the AFR sits as 14.4:1 for 15sec every time when cold then steps down to 13.5:1. Changing IVT multiplier only causes the 13.5:1 to dip into the 12's and makes no change to the 14.4:1 section. Is there an afterstart enrichment setting somewhere or is this altered by changing cranking fuel settings?
Any ideas? I just think it would be better a bit richer as the idle doesn't truely stablise until it richens up to 13.5:1.
Cheers,
Mike :grin::grin::grin::grin:


Two points.....


As Joel has said, you may need a bigger hole in the TB for the initial cold start. Looking at the shape of the commanded spark curve lends weight to this point. An average command idle spark that is higher than that set in the tune is a good indicator that you need more air flow. The only thing trowing me a bit here is that your are only pulling 12.5gm/Sec avg ( 14.2 peak ) after the start.

For the lean region, there are a few things to try.

Ensure the VVE is correct in these cells: It looks like it's pretty good as the fueling is correct after this time.
Dynamics: Yes, I bang on a lot about this, but dynamics seem to come into play a lot and at times you don't always expect. try this....

{B2012}: Copy the values from -40' to 8' and paste them starting at 8'. In fact, I've found this table to really need a full rework for my car and it's only got a small cam. I've reworked the table and it looks nothing like the stock one. It looks more like a VE table.....
{B0182}: Cranking fuel mass blend. I think this may help a lot. I'm not totally sure how this table works but I assume smaller numbers should keep the mixture richer for longer after cranking. So maybe drop the values below 30' and see what happens.

[hymey]

Looking at the cranking mass blend, also dynamic fuelling is very sensitive, dynamics can make or break a tune.

[The Alchemist]

Ok further info for the needy.... in trying to get the perfect cold start (is there such a thing) I had changed my desired idle speed at 8 & 20degC from 1000rpm to 950 rpm...god knows why...but I think this relates directly to an airflow value table (that we don't have access too yet ) like in the LS1's that is translated into a throttle blade position. This maybe y I can only get 20.4% TP. I discovered this only by looking thru my old logs to discover that I used to get 21.5% throttle cold starts a couple of weeks ago :) and compared my tunes. The only change I could find was the desired idle speed at 8 & 20deg. Will try tomorrow and post results....you guys may already know this anyway.
Also on cranking I have found that the engine for the first 2 secs runs on base idle timing before commencing any idle spark trim. This is helpful to know as the spark the engine runs has a massive influence on crank to idle transition and can be used to control the flare or the dip just after the actual crank flare retard bit (with the -10 max) but before the idle spark trim kicks in. Excellant results now.
Cheers,
Mike

[hymey]

Mike I would be setting B1602 much higher at cold ECTs for eg, If you have a later os it will be around 0.5, this is only double hot ect values, which will not quite be enough to max the values out. If your min idle air is 8 g/s hot you may need them to be much higher to max out the throttle. I would enter say 2.00 in here at cold ects or 4 if it is earlier o/s.

[ringram]

Ok hymey post the fix up :)
My tune is above. Ive not swapped the throttle yet. The only way I think it will idle with that hole is maybe with less timing.
Thats because the blade cant close any more. But more than happy to try your tune tweaks.

This is where I left off with the 7mm hole and some tables dropped back.
Or should I try the tune you emailed me? (I assume it was you?)

[hymey]

Ok hymey post the fix up :)
My tune is above. Ive not swapped the throttle yet. The only way I think it will idle with that hole is maybe with less timing.
Thats because the blade cant close any more. But more than happy to try your tune tweaks.

This is where I left off with the 7mm hole and some tables dropped back.
Or should I try the tune you emailed me? (I assume it was you?)

Hi Richard I have not fixed it yet, but glad your persistant with me I hope to fix it for you. I did have your email a while back too? Can you please pm your email address for easy transfer of tunes, and I will work with you closely on it to get it sorted.!!! I have a feeling you may need to drop down quite low with B1652, Some o/s like to have it around 0.7 before it starts to respond for some unknown reason!!!!

I will look at it today,.

Joel

[Naf]

I have followed everything you all have said here, and my idle is MUCH better, however i have a couple quirks i cant iron out. I am runnin a 214/220 with a 114LSA on a 6.0 2ith LS3 ported heads...

1. My idle is lean and i cannot richen it at all without messin with the rest of the MAP
2. My idle in Drive is a tad rough
3. when i am stoppin from a movement, the idle dips below 500 then jumps up...See attached

What is too much min Airflow?

[ringram]

Ok, update from me. I decided to epoxy up the hole and retry perhaps with a smaller hole.
BUT after speaking to Jessie from Waitforme at PRI did some messing with B1650 Max ETC area and what do you know. All seems well now.
Way, way better on cold starts than before and NO HOLE! I told it the area was smaller. Im guessing all the tables we cant see and corrections etc now think the throttle is small so it has to move the blade a larger amount.
I cant remember if Jessie said to make the value larger or smaller, but figured Id play around anyway.
So before anyone drills anything Id try this table first.
I can now drive at idle in 6th gear at 32mph on the flat, no jerking or lurching. Mind you cam is only 227/243-113

[swingtan]

Excellent info there ringram!. I'll have a play with this as I've been hunting for a low speed, low load surge for a while now. I've also "reduced" the commend cranking air in my car and found it starts better.

On a different note, I thought I'd offer a tip on idle fueling for those still running a MAF. It seems that on some E38 OS's, the ECM will drop into SD mode for idle fueling and no amount of MAF adjustment will help. I get the feeling that it's what is termed "closed loop idle" in some OS's, where the "closed loop" does not refer to O2 trims, but to the airflow bias between MAF and MAP. At certain idle settings, the MAP takes precedence even if the MAF is not in a failed state. I'm still working on this one though.

Simon.

[hymey]

Ok, update from me. I decided to epoxy up the hole and retry perhaps with a smaller hole.
BUT after speaking to Jessie from Waitforme at PRI did some messing with B1650 Max ETC area and what do you know. All seems well now.
Way, way better on cold starts than before and NO HOLE! I told it the area was smaller. Im guessing all the tables we cant see and corrections etc now think the throttle is small so it has to move the blade a larger amount.
I cant remember if Jessie said to make the value larger or smaller, but figured Id play around anyway.
So before anyone drills anything Id try this table first.
I can now drive at idle in 6th gear at 32mph on the flat, no jerking or lurching. Mind you cam is only 227/243-113

Thats good to hear Ringram, I noticed you had values of over 2 in max idle area which would not work with a hole in the TB, with the earlier o/s you can get away with a smaller hole(or in your case-no hole) but I can guarentee u I could get it running better with a hole. The blade just trims to far. Trust me after years of hard work on this and fixing a crap load of them (I have learnt the hard way) I can honestly say I have seen people come to me very happy with there tuners results with no holed TB to then drive a car with a stock like cam. I can only tell people the method I use. Just like a uni lecturer they give out the info weather the student can grasp it and make it work for themselves is another thing. But all in all I am glad you got it running and sorry if I lead you down the wrong path..again though as shown by the video before a car 220s duration on 112 lsa in an early o/s e38 with 7mm hole idling like stock. Cold start is relatively simple aswell. Infact I have a car in the workshop here with a 230s cam on 110 and drilled it 7mm once its tuned will post up some vids.. BTW I am glad guys are reading this stuff and messing with the max idle area tables.

Cheers

[ringram]

No worries mate. As you say as long as everyone has the tools in their tool bag they can select the one that works best for them :)

[hymey]

I spoke to Simon the other day about integral and proportional tables integral being short term and long term being proportional. If anyone has read the thread you will see some stuff on PI controllers and how they work with the 'P' being a learnt value and 'I' being a direct input by zeroing out the P table like you can do with long term idle trims in LS1s this allows any memory to not be used and allows the car to run on the direct value. I myself tried this the other night and found the min idle air much more responsive to changes without the need to reset the pcm all the time so good stuff Simon.

I have a vid here that I am experimenting with I have setup a 4 barrel manifold on my VE-G8(248-254-106 cam 40 deg overlap) and I can switch from carb back to efi in like 2 hours(yes a carb) just by changing the regulator and reconnecting fuel rails and some minor tune changes. I am amazed at how well super sedans run with massive cams and idle at 800 rpm and just bump over but super responsive with there competition carbs and powerful ignition systems. So in a sense I am playing with the e38 to obtain a correct idle while no injectors are there just thought I would show people it can be done. Vid is a little dodgy but its just an update on the progress(getting there). The car has a nitrous setup can go upto 300hp. I also have a large garrett turbo here I would like to setup blow thru carb. Will see how we go.

http://www.youtube.com/watch?v=EFqKZ_CWAok

http://www.youtube.com/watch?v=ORiZ5kd1580

sorry bout ordinary filming lol

[swingtan]

Ringram: I've made some initial tests on a "smaller" cam (220/224) and found that B1650 has an interesting effect. I like it so far but the verdict is still out on the light throttle surge. I found that reducing it too far, resulted in a hanging idle when cold and the normal ECT correction table needed a lot of work to try and correct it. So I increased it to about 80% of the stock value and it seems fine. I still get a small amount of surge so may need to work on some dynamics again.

Hymey: Those tables can give some good results, don't they. As mentioned, I zeroed out the few cells around 0 RPM in the Proportional table to help with idle control. I'd found that my engine idled better if it was commanding slightly more air than it really needed. The problem was that the Proportional table would pull too much air out and the idle would go rough. I was consistently adding 0.5gm/S to the min idle air, then it would learn down and run rough again. So I zeroed the cells and all is good now. Min idle airflow is what I want it to be and the ECM does not remove addition airflow.

Simon.

[hymey]

Simon, It works wonders, infact I seen it zeroed out in a stock 09 VE clubsport OS. So HSV been playing too;). They definately like to idle better with a little more air and lesser amounts of timing. The cams people mainly use arent that big and don't call for large amounts of timing. The motor needs to breath at idle. You just command what idle air you want and it responds basically , the integral tables do a fine job trimming the air and getting as fussy as we do now means proportion is not required. And it sure does mess things right up at times.

The only real fix for surging I have found is lowering B1651 a little and running in openloop. This helps a lot.

Also It has a lot to do with the engine. If I put a 230s cam in dot to dot and cam is retarded it will surge in CL. If I then fit a new timing chain and degree the cam with a rollmaster etc So it is advanced say 2 to 4 degrees. No more surging in CL in most cases. 3.9 and 4.11 diff gears will eliminate it with a M6 once you have the tune right they drive amazingly like a stock car or better!

Joel

[hymey]

Ringram: I've made some initial tests on a "smaller" cam (220/224) and found that B1650 has an interesting effect. I like it so far but the verdict is still out on the light throttle surge. I found that reducing it too far, resulted in a hanging idle when cold and the normal ECT correction table needed a lot of work to try and correct it. So I increased it to about 80% of the stock value and it seems fine. I still get a small amount of surge so may need to work on some dynamics again.

Hymey: Those tables can give some good results, don't they. As mentioned, I zeroed out the few cells around 0 RPM in the Proportional table to help with idle control. I'd found that my engine idled better if it was commanding slightly more air than it really needed. The problem was that the Proportional table would pull too much air out and the idle would go rough. I was consistently adding 0.5gm/S to the min idle air, then it would learn down and run rough again. So I zeroed the cells and all is good now. Min idle airflow is what I want it to be and the ECM does not remove addition airflow.

Simon.

Another note B1650 if changed will alter TP% reducing it actually increases TP%, so if you get 9% TP% you maybe getting 15 or more % just a guess really.

[ringram]

I think it will act on some hidden airflow calculations. (ie) I need 10g/sec so given ETC area y I need x% ETC.TP to deliver the 10g/sec, of course a "smaller" throttle means greater x% for airflow.. So its tricking the ECU, but whatever works :) Given mine is skewed due to limited IFR another skewed value is ok. Thanks to Jessie for the heads up.

[hymey]

Sounds good, I have read some of the HPT guys doing it, A lot of guys there having issues with things it is easy to mess things up. I redid a car last week had been to so many shops I had to start again. The main thing is the hard limit, even if you change the multipliers the hard limit is still there changing b1650 it still thinks its the same but you get more percentage. Just make sure it is getting full throttle when it should be. Cold starts is easy to sort I am more concerned how your idle is with the TP% trimming. As simon mentioned he has also opted to not drill his which is a personal preference. But he also said his idle does move around a little because it steps 0.4% at a time. I'm a little different and I the way they end up changes the note of the car, A lot of commodore owners approached a friend of mine during powercruise asking the same. The airspeed buffer works wonders:)

Another thing that must be considered is dynamics. Again I base these ideas on speed density. Tuning the MAF at idle takes longer. SD gives a better idle with big cams. Also most tuners in US are using MAF based tunes. When they go over to speed density with e38 they are treating it like a ls1 o/s(not altering dynamics) and if dynamics isn't right it results in very poor drivability and lag in throttle response. WOT tuning is also an issue. With stock dynamics and SD the car will ramp up a nice number and afr curve then on the street low gears will be lean at WOT with lean spikes during shifts resulting in very poor performance. The first thing they do is put the MAF back on in which if they don't know what there doing is a very good idea.

[ringram]

Yeah I think cold start dynamics needs tweaking. More fuel required. Though once warm its fine. I have too much throttle response with 440 cubes and a 227 cam as it is.

[hymey]

Whats your afrs at cold Rich?

cheers

Joel

[ringram]

If I ever get my car back from the guys learning at my expense Ill tell you!
I took the WB out for warranty work a while back. Ive been without my car for basically a year, its just gone back for an oil leak less than 1000 miles after a £10k rebuild.
Not pleased.
Anyway, Ive no garage, so need to wait until its semi dry to roll under the car and fit the WB again. Ill get some NB O2 MV info for a rough idea if/when I get the car back!

[Tordne]

Despite originating in Australia it is a British car now so it is supposed to leak oil. Seriously hough, that is very bad for the amount of time and money you've put into that thing. I take it back now, it may just have been cheaper to get the ZO6 :)

[hymey]

Is it a rear main leak Rich? I have heard some guys puting the reverse lip seal in back to front to combat oil leaks, especially with engines with forged pistons with larger ring gaps and piston to bore clearance, they tend to have a little more blow by and can cause this.

[hymey]

Just an update, Thanks to Simon and a few tips(which were actually brought up at the beginning of this thread). I was able to get my best drivability results with this cam 6L L98 upgrade. The cam is a 233 238 on 110+2 @ .600" lift. After I installed the cam I nearly died when I seen how minimal the ptv clearance was on the intake. All I can say it is safe for a race engine and more then what some people run so I spent a bit of time trialling differnt pushrod lengths to minimise preload just incase it gets valve float and pumps up. After a few hours I was very happy with the valve train setup,

This cam has 15.5 degrees overlap the end result I am very pleased with, performance of the engine is the best I have done "cam only" by a long shot, but the drivability was also the best I have done. The moderate duration tight lsa cams work very well and will behave if tuned correctly.

Idle was very simple. This time proportional tables zeroed out, 6mm hole in TB. B1652 1.15 and B1651 0.6. Integral tables, well looks like GM sacked there old tuner because they look a lot different, and it appears to me there tuners are learning the e38 at the rate which everyone else is...very slowly. lol. I tweaked the coast down integral table making it a little more aggressive, timing correction as per normal, 15 degrees idle timing, idle air was 8 g/s(mind u I didnt even follow the steps I normally do I just plugged the values in above and left it) Getting rid of LT idle trims helps a lot. Makes it so much easier. I ran 30 degrees in coast down table and ran less airflow on coast down to stop the chugging around roundabouts. Drivability tune was then complete but I decided to go on a 20 km fuel economy course and just keep an eye on the engine parameters. In 6th gear at 1500 rpm the car sat at 100km/h but it had a surge that was annoying and wasn't helping economy. Typical of a cam of this size. The air fuel was on the rich side in the high 13s, I tried even 13.2 it still had the problem. I new then there was a reversion and atomization issue in the chamber. The Ls7 injector does not have the best spray pattern. I decided to follow some ideas I had doing aftermarket engine management and that is to trial injector timing. By firing the injector earlier while the valve is still closed it gives the fuel more time to atomize. In GM's stock tune it is setup to allow for maximum fuel economy and emissions. A late injector fire that leaves little amount of fuel residue on the port wall.

A trick with injector timing is to advance it till the afrs are at there richest for the given pulse width. This proves that all the fuel is atomized that enters the chamber. If you keep advancing afr can drop off a little leaner which means the fuel maybe suspended on the port wall. Standard at 92 ect the injector timing is 220 degrees then the rpm table adds to this as rpm increases. I was able to go up to 400 degrees total at idle and cruise then build to around 480 at peak rpm. This cam took a lot more lead then most others do as well 31 deg at peak torque was MBT. But cruise at 38 degrees was terrible. I went upto 50 and it still wanted more but the engine did love 50 at cruise. With the injector timing and ignition timing dialled in the vve took some more work. I was running much richer this was a good sign, I was able to lean back to stoich at cruise and have perfect drivability. Running 30 degrees in coast down timing and correct coast down airflow eliminated any chugging on and off the gas. I stopped for a quick drink and let my mind rest...just for a minute and made a flash for minor timing changes. On the trip back home over 20km of country and then city driving it was a totally different car. It drove like stock just as it did when the customer dropped it off. I was very happy with the outcome. From 1000rpm in 6th pulls away like a stock cam,Most stuff of this size carries on like a pork chop! All up 6 hours work on drivability. Airflow , timing, vve and injector timing all playing equally important roles. Injector timing makes a big difference on high overlap cams. You can reap awards with aggressive cams and drivability if you focus on these areas.

Cheers

Joel

[VEV8]

Joel what settings do you normally run for "airflow correction coolant multiplier"

[swingtan]

VEV8, you need to run what the engine wants and every engine combination will be different. It's also very dependant on your base idle airflow. A guide for working out that table is to log the spark and see how it compares to the tune settings. The ECM will try and control the idle speed by adding or removing spark advance. If the logged spark is higher than the tune settings, add more air. If the logged spark is lower than the tune settings, remove some air. So all you need to do is to watch the spark as the ECT rises to see what sort of airflow is wanted. Remember to rest the learned data before trying this though.

Simon.

[VEV8]

Thanks Simon...So it doesn't necessarily matter what the factor is, i can just alter minimum idle airflow to suit. But does the factor also play apart at higher rpms as well
I already knew about watching average base spark at idle to get an average airflow required.. originally my OS was a factor of 2 & was scaled down to a factor of 1 at full operating temp.. Later OS i seen were 0.5 down to .25

My setup is a 224/228 cam with a 5mm hold drilled in throttle body,13* idle spark.... with my original settings i had a minimum idle airflow in the 6's (which i thought was quite low for that cam) and still had a rather high idle

I do have it idling quite well using a setting inbetween those two original settings, just wasnt sure it was a common rule to change this setting or just change minimum idle airflow only

[hymey]

Try zeroing the proportional table. It uses a PI controller. P being proportional learnt data. You can use a very slight correction factor in integral tables. And moderate timing correction. The e38 is so fast it will try and adjust timing to maintain idle speed. If the rpm dips way to fast it is a sign the min idle airflow is to low. If it hangs or timing is very low try removing some timing. The reason why I change B1652 and 51 is they have a big effect on drivability. But I run B1652 high enough that it will allow enough air on cold start. Usually 1.20 B1652 0.7 B1651 is a good combination with around 7 g/s across the board in min idle airflow. I have tried every combination possible with idle tuning I always end up around here. There is a very high possibility that the "learned" data will still be there, ie the Long term idle trim. You have to zero this out in the tune to get it right. 6g/s-7g/s is about right. Some people have had good results not drilling the TB aswell. But there min idle air will be much higher. I personally get them idling better with a hole but everyone has there own methods. Not zeroing learnt data will give you a world of trouble. The main method I use will allow you to find best idle air without worrying about the learnt data but when max idle area is raised the idle lifts back up. Thats why if I drove around for a few hours and then raised the max idle area value the idle would not hang as it had learnt correctly.

As simon and I discussed a few months ago. Zeroing proportion is the right thing to do. (All proportion tables) Then you will be very close.

My email is joelprince@bigpond.com if you want me to look over your tune feel free to email me or Simon. We don't charge here lol , just help each other out.!

[swingtan]

Thanks Simon...So it doesn't necessarily matter what the factor is, i can just alter minimum idle airflow to suit. But does the factor also play apart at higher rpms as well
I already knew about watching average base spark at idle to get an average airflow required.. originally my OS was a factor of 2 & was scaled down to a factor of 1 at full operating temp.. Later OS i seen were 0.5 down to .25

Yes, it does matter. The colder engine weill want additional air flow to help it idle and the ECT correction factor works across the whole base idle airflow table.


My setup is a 224/228 cam with a 5mm hold drilled in throttle body,13* idle spark.... with my original settings i had a minimum idle airflow in the 6's (which i thought was quite low for that cam) and still had a rather high idle

A 5mm hole for a cam that size is massive, way too big IMO. It'll cause all sorts of high idle and hang issues that may not be correctable in the tune. I'm running a 220/224 with no hole and I can tune it to idle like a stocker or have a big cam lope. I'd also look at increasing the base idle spark toward 20' to help with the idle. Don't forget to adjust the high and low spark tables to suite though.


I do have it idling quite well using a setting inbetween those two original settings, just wasnt sure it was a common rule to change this setting or just change minimum idle airflow only

I've altered the ECT tables a lot, as I've done on most other tables..... When you mess with the mechanics of the motor, most of the tune settings will need to be tweaked to suit the changes.

For comparison:

My hot idle is 700RPM
Min airflow is set to 7.8gm/S

For B1602: fromt an ECT of 80'C down to 20'C I have a steep curve startingfrom "1" @ 80' and rising to just under "1.7" @ 20'. The graph angle then drops off to a value of "1.8" @ -140'

The E38 and 6lt motors like to be over fed idle air if you want it smooth. The E38 seems to do better at reducing idle speed, than increasing it, so err on the higher side and it will be easier to tune. Also as Joel says, for B1845, zero out 2 to 3 cells above and below "0" for each "idle correction type" then blend the remain cells. Once you have optimised the idle tune, the Proportional table becomes less important.

Simon

[hymey]

They definately like more air then less, I normally run a hole around 4-5mm for that size stick to get them idling how i like and end up around...6gm/s with a dead smooth idle at 800 rpm and 13.5-14 afr, 15 degrees timing (no correction) and zero lope. That size hole wont cause you any dramas if u set max idle air up correctly and min idle air. Twin turbo stuff with stock cams I drill 3mm holes to help the surging at idle and pulsing by the compressors.

You will find they like more air then less. My 248-254-106(admittly a carb) using stock pcm for spark idles at 20 degrees timing at 800rpm and NO spark correction, And it idles like a 224-228 would in LS1 terms at 14:1 afr and idle very smooth. The trick to this is consistent idle spark and airflow. Any changes in airflow and spark will disrupt the idle to a degree and cause it to hunt up and down by 50-100rpm. My carb has a 4mm hole drilled in each butterfly (yes four of them) so they sit in the correct position with 40 thou of the transfer slot exposed. My TK cam had an 8 mm hole in the TB I had to keep going bigger with the airflow "maxxed out".

I still prefer the original method of maxxing out max idle air. I can arrive at the point a lot faster. The integral correction is still taking place otherwise I try to eliminate that. The amazing thing is if you "lock out" the air you can then push the timing up and down(with no correction) while datalogging and engine running, I keep the air fuel in the high 13s and then raise the spark up and down until I get the best idle vacuum. In most cases then I run very minor correction in both timing and throttle like -3 deg max for timing and 0.080 for integral as a max number. Thats how I get them with a standard idle. Usually at the drags/etc combined with varex mufflers it passes as a 100% stock engine at idle. Fuel economy drastically improves around town and it really passes as a stock car to drive, Most people even if they love a tough sounding engine always go this way as it is so much better to drive. Most tuners just try to get the car driving and eliminate hunting and stop there. Go beyond that. Lock airflow, adjust timing with DVT. get in open loop Note down the max idle air, and adjust timing, increase air try different timing again. Once you arrive there establish min idle air and get the corrections to a minimum with a bypass in the TB. Cold start and drivability it all goes hand in hand.

[VEV8]

Thanks Joel & Simon... i am pretty close now.. i zeroed the proportional table, set max idle air to 0.7 & 1.0, 15* idle spark, warm idle at 770rpm, 7's in minimum idle airflow, coolant modifier is 0.6 when warn (still had hanging idlle & low spark with anything more then that)

Its very close now i think.. may need to look at spark correction in gear setting to get it even smoother

[swingtan]

Oh it's an auto? Guess what, autos in gear are the easy ones to tune :p. The additional load of the auto helps smooth out the idle a lot. Good news that you're getting close though.

[hymey]

What o/s is it some of them run 0.25 with the coolant multiplier hot and 0.5 cold. Others run 1.00 hot and towards 2.00 cold. Why? I dont know. If I use values from my o/s which has 1.00 and put them into an o/s which has 0.25 at full operating temp the idle hangs! There still both e38s and both end up with the same min idle air but the multipliers are different. Just something I picked up. If u do want to experiment with a smaller hole I have a spare TB here somewhere I can send down to u.

You can also setup B0148 for OL fuelling tune the car with that then enable PE at 90kpa. I have great results doing this. Use Simons VVE tuning guide. I have been chatting with Girch from LSX tuning, he runs 90% of his VE;s with the MAF. Something Simon and I have preached all along and I do remember Girch actually disagreed with me on this 3 years ago but 12 months ago he came around and admitted that MAF tuning is the go and will deliver the same rwkw top end and have much better drivability. Something I thought I would add if you are currently in tuning mode. To put in perspective Simons engine is the most tuned LS engine in the world by far I would think, He has tried all combinations in different cells and still goes back to the MAF. It does take longer to get right as you dial the vve in first then scale the maf. But maf tuning is definately fun and enjoyable and the fuel curve is rock solid and consistent with awesome response. THought it would be wise of me to preach it to you! You can also command a 16:1 stoich in OL MAF and use B0148 to multiply it like a ls1 cos. Run it lean at 15.5:1 cruise and 14.7 idle etc. The OL maf has better results the dynamics work so much better and the car has better partial throttle feel which helps a lot at cruise.

BTW I live in Gladstone another QLD e38 tuner!

Cheers

[VEV8]

Thanks Joel,

Im currently running CLSD (dont have any experience with maf tuning) and running a reasonably rich VVE and bringing PE in earlier 65/70KPA to be safe.. I will post my tune for you guys to run your eyes over and see if anything obvious needs doing that i have missed (Dynamics ect).. I would like to run a little leaner in the cruise cells and idle for fuel economy

[VEV8]

current tune

[The Alchemist]

106241062310622
Hi Guys,
Got this supercharged ute back with starting issues. TVS2300, mild cam 230ish, other supporting mods etc. What its doing is: the 1st cold start starts perfect and runs no problem, takes a throttle, mixtures good etc etc, let it run for a while say to 40 to 50deg C, turn it off and start again immediately it will start fine 1st crank but as it comes down to idle it just stalls and each successive try to restart it gives the same stalling issue. Walk away have a coffee calm down, try it again and it starts and runs perfect. I have included a log and what is most noticible is:
on the 1st start of the day and the problem ones is that the IPW drops out to 0.9ms just after starting and the LOAD drops out as well to almost nothing even thoug the engine is at 1000rpm or so. Pumping the throttle does nothing as the engine is on its way down by then and the IPW just keeps sitting on 0.9ms.
The ECU is configured MAFLESS with the MAF unplugged.
Any ideas on where to look? Thanks,
Mike
http://forum.efilive.com/images/misc/pencil.png

[Naf]

106241062310622
Hi Guys,
Got this supercharged ute back with starting issues. TVS2300, mild cam 230ish, other supporting mods etc. What its doing is: the 1st cold start starts perfect and runs no problem, takes a throttle, mixtures good etc etc, let it run for a while say to 40 to 50deg C, turn it off and start again immediately it will start fine 1st crank but as it comes down to idle it just stalls and each successive try to restart it gives the same stalling issue. Walk away have a coffee calm down, try it again and it starts and runs perfect. I have included a log and what is most noticible is:
on the 1st start of the day and the problem ones is that the IPW drops out to 0.9ms just after starting and the LOAD drops out as well to almost nothing even thoug the engine is at 1000rpm or so. Pumping the throttle does nothing as the engine is on its way down by then and the IPW just keeps sitting on 0.9ms.
The ECU is configured MAFLESS with the MAF unplugged.
Any ideas on where to look? Thanks,
Mike
http://forum.efilive.com/images/misc/pencil.png

So it starts up after initial start up. Thats a good thing, but what is your Min airflow set at? Also your airflow correction to coolant multiplier may need a tweak.

I wouldnt know where to start on the IPW

[hymey]

I had this the other day, There are some tables that help the engine recover airflow if it dips. B1833 and B1844 you can set these to less then 1.0. It seams a strange issue. Remember with the engine colder it needs more fuel on cranking then hotter. I have found that the cammed engines require much less fuel on crank . B8062 try this set down to 75%,

If an engine does this it normally means it is performing tests to see if the maf is there, the e38 will perform these tests over a few seconds on start up. Some engines actually are more sensitive then others ( and some e38s) unfortunately I have found that all cars and e38s respond differently, they all throw curve balls so when you think you have it nailed it comes back and bites you.

I think it is definately fuel only issue before you change any other settings try this.

C0310 set from 1 to 0.

C0312 set from 400 to 100 rpm. Ensure all other parameters in maf diagnostic tables are completely stock. I have seen this scenario on my car.

Make sure P0101, 102 and 103 in DTC type are not set to not reported, they should be B: 2 trips, emissions related or C: Non emissions.

[swingtan]

I had a chat with Mike yesterday and after going back and forth a bit, Mike realised that it only occurred when the MAF was disabled. We reset all the DTC types and then tweaked the MAF tests to ensure the MAF was failing and it all came good. We think that the ECM was taking too long to fail the MAF, so it's think there was no air flow, pull the fuel out and then by the time it realised the MAF was dead and it swapped over to the VVE, it was just too late and the engine died. After tweaking the MAf tests, it's all good now.

Simon.

[hymey]

I thought so it happens a lot with e38s but i set the timers all to 0 and the test enable at 100 rpm in all of them now and they fire right up.

cheers

[The Alchemist]

Legend !. Thanks Swingy...
Now if I could only get the throttle to open more than 20.4% at any given time to help cold idle reach target of 900rpm .....Tried B1651 52 at 4.5 and still no improvement...any ideas
?

I had a chat with Mike yesterday and after going back and forth a bit, Mike realised that it only occurred when the MAF was disabled. We reset all the DTC types and then tweaked the MAF tests to ensure the MAF was failing and it all came good. We think that the ECM was taking too long to fail the MAF, so it's think there was no air flow, pull the fuel out and then by the time it realised the MAF was dead and it swapped over to the VVE, it was just too late and the engine died. After tweaking the MAf tests, it's all good now.

Simon.

[hymey]

This is where I get stuck and I must say I am a bit at fault for not mentioning the different o/s. I am in bed with the flu today and while it sux I get to go on the forum lol. B1602 varies from o/s to o/s some are topped out at 0.5 cold start others are at 1.0 cold start. A lot of the 2007 cars and also the VZ e38s have it to 1.00 at cold hence why they go the bigger hole they have to much air. I use the later table in these cars and run the bigger hole and they idle very nice. I have done two this week, one I built the engine it has a 239 239 lsl cam and runs in SD closed loop, the other is a 2008 VE maloo I put a 230 xfi 230 xer 111+2 cam in it. They are both well behaved. What I do in some cars(when I am time limited) is turn off the proportion which is the learning parameter, leave integral stock and flatten the hole min idle airflow table and tune for best idle air at 800 rpm. Then also also at 1000 rpm. I set the idle at 800 then put 4 g/s higher in the 600 rpm table, 2 higher at 1200 then a 1000, and 3 higher at 1600 and set max idle air at 1.50. This combination gets me in the ball park. I then push the multipliers around, So I get it idling at say 800 rpm and raise the multiplier till the TP% comes up and it hangs a little then back it off .05, see how it looks then .1 from the target and I know my bottom hard limit is reached. Doing this with a 5-7mm hole with mid size cams makes them idle so smooth and when i post the vid up you will see why I still use the larger holes, they just behave so well. Max idle area will change that upper limit to a degree but once you hit the upper limit thats it which changes in some o/s. My only suggestion is you try the multiplier B1602 in cold ects. Try and raise them it may come up to 21-22% region. It may work or may not I have not had the issue.

Another thing with maf tests in sd mode. If you have the airflow squared away with the maf, you have the scale right, and the vve correct. Sometimes when you disconnect the MAF you will notice after 4 seconds or so you feel you have no throttle and it bogs a little then goes. That is the maf still doing its tests. I alter the diagnostic tables aswell to stop this.

I remember back in 08 when I was drag racing my car- bolt on at the time I was stopping it starting it waiting to go through scrutineering and I was starting it engine would conk out and stall, then I would reflash it would start. Then stop a minute later same thing would happen just like your customers car. The scrutineer was going off , I ended up getting it started and just not turning it off, I eventually worked out to drop the timer, The VZ 1 meg o/s do this aswell.

Cheers

[The Alchemist]

" My only suggestion is you try the multiplier B1602 in cold ects. Try and raise them it may come up to 21-22% region. It may work or may not I have not had the issue."
Hi Hymey thanks for your help ...this table I already have at "2" up to 32deg C as per an earlier suggestion you made a while ago....20.4% seems to be the max it goes to .....
you can see how it stays on 20.4 right up to about 55deg c before the spark has lowered enough that the TB starts to drop to 19.5 and so on .... Even when fully warmed up and you engage drive but remain stationery the TPS goes to 20.4% and the timings at around 28 deg to try to acheive target idle of 800rpm...

[swingtan]

I've been playing in Excel a bit to try and confirm . deny a theory I came up with when talking with Mike yesterday. My theory is that the E38 uses both absolute throttle blade position and effective throttle area (as a percentage). But there is no indication as to which is being used when. This helps explain the old PE TPS graph that I went through a couple of years ago.

Anyway, I've been plotting the data out and it seems to fit in a general sense, but it's not quite there. It has helped explain a little about the hole drilling method though....

When calculating the absolute blade position and comparing it with the effective throttle area, we see that at low throttle openings, the effective area rises sharply compared to the blade position. This is because the blade tip moves through an arc from the top / bottom of the throttle body, toward the centre line. The throttle effective area is then the "gap" between the blade and the inner surface of the TB. Initially this gap widens quickly, but after a certain point (about 35% of blade position) it slows down and the change in effective area nearly matches the change in TP %. Then a short time after, the effective area changes slower than the TP% (about 65% of blade position ).

How this relates to the holes in the throttle blade can be seen when looking at the nominal Idle TP%, seeing the matching effective area and then looking at what the hole does to the situation. Here's an example.

My car normally idles at around 6% as indicated via the ETCTP PID. This gives me 8gm/S of idle air and all is well. At this pint I have an effective throttle area of about 21mm^2 which is 0.44% of the total throttle area.

If I drilled a 5mm/Dia hole in the blade, I'd introduce an additional 20mm^2 of effective throttle area, which would double the effective throttle size. So I'm going to assume the ECM will almost close the throttle to maintain the desired airflow. At this point, the ECM can not 'reduce' airflow, as it can't block the hole in the TB blade. So you have effectively removed the ECM's ability to reduce the airflow below this point.

Personally, I've never drilled a hole, possibly because I've never had a car with a big enough cam to need it. We know that the E38 likes to over feed the motor with air, as the engine seems to idle better, so the hole seems a good method to hard limit the minimum air flow. I'm pretty sure you can still do it in the software, but you can't make the hole smaller in software....

There are a couple of other things I'm still pondering....

The difference between {B1650} and {B1701}. One is set for a 78mm dia throttle and the other for a 102mm Dia throttle. Why the difference? Something to think about.

Simon.

[hymey]

Yeah depends on the B1602 parameters simon. If I run no hole, it idles quite high percentage, if I drill the hole it reduces by 4%, this is real testing though. The only reason I do it is to stop the pulsing of the air at idle, you hear the slight air differences. So if I use sae.tp it idles at 20% idle with say a 232 234 112 cam. I only have 1 % left for cold start. If I drill a hole its back to 15-16% roughly. But the issue is with the L76 o/s is they won't idle less then that region, whereas the later o/s will. Hence why they have "0.25" at 92 degrees in the B1602 multiplier. Change to this like Holden did in all there o/s, then 8 g/s really is much less g/s and you get real world figures. All the cars I do idle stock even with 239 cams, they wont get there otherwise. I have tried the car idling hot. No hole, And then worked on the integrals for two nights straight. Im bipolar and had a bit of a manic stage for 48 hours of solid e38 tuning a week ago, I tried the stock B1602 settings and then worked hard on the airflow tables and integrals also altering integral limits (which helps) I would aim first at a thousand and it idled OK, but the rpms moved around slightly and it was very choppy. I would increase the hole, alter the airflow tables and also changed the B1602 settings to the later setup, and the car progressively got better. I also done away with the L76s horrible pcv system and went to the later L98 setup and valley cover. I just kept going bigger (I have a spare blade) with the multiplier set to 0.35 max at lowest till I found the hard limit, then went down to 0.25 at 92 degrees, and min idle air went

10.00
10.00
6.00-----800 rpm
7.00-----1000 rpm
9.00
10.00

Now big cams and blowers need a TONNE of air at cold start. I have plenty at 20.9% cold start just like a stock car then work down to 6 g/s at hot like a stock car so the whole system is essentially working factory like. You can change the effective area values. I have never changes these and dont want to alter wot settings which it may do?

I ended up with 7mm in the 239 car. I tried going smaller just to test it as a few guys with bigger cams then this car suggested they had but I ended up with the best results doing this method. I never used an excel sheets or data logs. I just listen to the motor and do whats best for it and the customer and they drive stock. The bigger hole also makes them a lot smoother on transition and also start a lot smoother. The main reason is for the airflow buffer. Simon your car would have a larger area going from the passenger rear tappet cover to the manifold which will act as a hole itself and give extra air plus act as a buffer. The L98s/LS3s have the later restrictor in the cover which doesnt appear to give any more air. If I block it or not it does not effect idle timing. If I did that on Bens L76 it would change the timing quite a bit, just thought I will let u know that. I am pretty sure I have it covered now to the best of my knowledge. If I started again on this thread I would change a few things I do but overall it is the same out come and I think to this day I am pretty confident with what I have done with idle tuning. I have been thrown a lot of curve balls. I know some guys like to change things just in the tune but it is still a motor, like make the cam timing retarded and intake biased and you will work a lot harder in the tune to get it right. I have a method that is 100% proven, the only thing I do differently now is ensure the L76 pcv systems are modified and also work on the B1602 multipliers to help set upper and lower hard limits. I do also do what Simon does and that is zero proportional tables and keep integrals populated and play a bit with that method aswell as max idle area. The rest just comes up with the tuners ability to see the problem as it arises and how to go about fixing it.

[The Alchemist]

so it seems that 20.4% is THE HARD UPPER LIMIT for my Max idle % ? Does this sound about right...ie even increasing b1651 52 from "1.8" up to "4.5" did not change the max idle over 20.4% at any given time....Looks like drilling a hole in the TB IS the only option left for me ...surely other people with S/Chargers must have had similar problems?

[swingtan]

Try increasing {B1650}, maybe it'll allow for more throttle.

[ringram]

I had same issue, not enough air no matter what min idle airflow. As above b1650 definitely puts more air in.
438 cube with 230\240 cam.

[swingtan]

Thanks ringram, I thought that may work. Was I right with increasing B1650 to allow for more air?

Simon

[The Alchemist]

I had same issue, not enough air no matter what min idle airflow. As above b1650 definitely puts more air in.
438 cube with 230\240 cam.
So I've got 4725 in here...what should I change it to ? Add 2%? 3%?
Does this setting affect anything else?
Mike

I've gone 5% increase and try that tomorrow on cold start.

[The Alchemist]

10761

Making b1650 smaller opened the throttle further :) I lowered it 5% to 4488.8 and the tps opened up to 21.2% where previously it only opened to 20.4% . this gave me a near perfect cold start and target idle 950 rpm met with about 26 deg timing instead of about 34 !
awesume!
Next day:
Went -10% B1650 to 4252 and tried it today and got a high starting flare to 1700rpm and a tps of 21.6% cold engine. I also increased 1651/52 to 4.5 & 4 incase this was holding the throttle from opening past a certain "point"
The extra 5% decrease on B1650 only increased the TPS from 21.2 to 21.6% so I'm going to increase B1651/52 to 5.5 & 5 (raising the hard limit) and see if the TPS opens a bit more.
B1650 obviously affects other tables such as cranking idle air as it now flares badly on startup. Timing now down to an average of 26deg cold engine idle.....
Interesting stuff really....
Does anyone have any theories on what is the difference between B1701 and B1650 please?
When you reverse calculate B1701 you end up with a throttle diameter or 102mm which I believe is what we have in the VE Holden V8s.....B1650 however is another story...
Mike

Set b1650 at -15% from original to 4016 and now getting 22% throttle cold start with even lower timing of about 22 deg. In gear drive hot or cold now ticks along beautifully at 800rpm as the throttle is open further vand the timing not over advancing trying to meet target. The other interesting thing is that starting at any temp now flares to 1700rpm BUT I believe this is becuase the throttle max opening has been increased allowing the throttle to open further on starting. Just my observations......Will adjust B1832 down by 5-10% or so and see how it goes

[swingtan]

I've not fully worked out the {B1650} vs. {B1701} relationship yet.

As you say, {B1701} indicates a 102mm dia throttle, but that's not actually the one in use on the VE. The lead in to the TB might be close to this, but the actual blade is much smaller. The specs say the vE runs a 90mm TB, but I'd say the blade is smaller still.

If you use the stock values of {B1650}, you get a TB diameter of 77.5mm, which is about what I'd guess it would actually be.

Why two tables with different values?

I believe the labels given for these are taken from the GM documents, so don't always read well when you don't have the full documentation. They need some context to really be understood. The only difference between the two is that {B1701} adds the term, "effective"....



Maximum effective throttle area of the ETC in square millimeters.


where as {B1650} doesn't use the term.

So I would assume that {B1650} is the literal setting for the TB size and is used by the ECM to calculate how much throttle opening is needed to supply a specific airflow. {B1701} is then possibly used as a correction factor, as there are times when the airflow may not match the expected flows. For example, peaks in the airflow may be at a level that match a bigger TB.

Still working on a full understanding.......

Simon

[The Alchemist]

10766new cold to hot log

this is my new cold to hot idle log with 22% max tps now with 22deg ave spark. smooth as silk now and you can tap it into gear and it just drives off like standard VE Holden :)
The rest of the log shows in gear and out of gear with the spark and tps adjustments that the ECu makes. I also dialed back cranking idle air and the 1700rpm flare is goneburger.
:grin::grin::grin::grin:
Also today with all this testing the ecu logged a p0606 code which apparently is not good. When this happened the start was very "saggy" and I had been doing a few start tests to sort the start flareup.... The water pump for the supercharger I/C also stays going if you leave the key "on"
Suspecting low voltage causing this to trigger I logged this time with ECU Voltage pid. It seems it takes 7sec after startup for the ECU to report that its got 14.8volts, infact it stays on 11.4V for 4 seconds!...Is this normal ? Never checked it before so I wouldn't know...What do you think? This would be much worst if you had just been doing startup testing a few times so this may have been the problem

[Dieselman]

10766
Suspecting low voltage causing this to trigger I logged this time with ECU Voltage pid. It seems it takes 7sec after startup for the ECU to report that its got 14.8volts, infact it stays on 11.4V for 4 seconds!...Is this normal ? Never checked it before so I wouldn't know...What do you think? This would be much worst if you had just been doing startup testing a few times so this may have been the problem

Battery voltage is all controlled by the ECU on the VE's. Mine can take a while before it all kicks in. I think it calculates charge rates and battery percentages during this time....

[The Alchemist]

10767

heres a log I did today showing a start then instant stop followed in 10sec by a start and everything OK. Logging batt and ECU voltage shows the voltage dropping to "0" just as it starts causing the engine to fall over.
Discussing this with the owner revealed that "yes" it does this every now and then especially after a short stop over into a shop or at the petrol station, but had never mentioned it to me .....
Something strange happening here...I'm going to check the charging and starting system tomorrow

[ringram]

Another convert ;)

Yes the B1650 setting seems to affect anything that happens when you drop throttle pedal to zero. So coast down, idle, transition, as well as startup etc.

[swingtan]

Not too sure about that one, but I don't think it's tune related.

Back on to {B1650} and {B1701}. I did some testing over the past week and set these both back to stock. I have a 220/224 cam, so nothing too big and it did idle fine when hot and cold. However, on a dead cold start, it would fire and almost stall straight after firing.

Example of near stall here (http://www.youtube.com/watch?v=t4CIcT2upD8)

This is where these tables really come in to play as I think they may influence the crank to idle air flow blending as well. I then pulled 5% from each table and the stall nearly disappeared completely, so I'm going to pull another 5% and leave it at that.

So my advice would be for anyone that is doing cold start tuning, to drop these tables to aid is stability between crank and idle as well as cold idle airflow control. Suggested starting amounts would be,

For a hot idle min air flow of...
[list]
5gm/S to 6gm/S: leave stock
6gm/S to 9gm/S: -5% to -10%
9gm/S to 15gm/S: -10% to -20%
[list]

The Alchemist has given us a good guide to dial the values in for fine tuning. Simply log the TPS% and watch how far it moves. Then use the idle spark technique mentioned earlier in this thread to fine tune the air flow.

Simon.

[The Alchemist]

Re: my starting issue falling over etc etc I removed that battery today and had it tested and its only doing 200amps at 9Volts
:( so am fully charging it on a 7 stage charger and retesting in 24hrs otherwise new battery time!
"Fully charged" at 50% CCA 7.2 Volts at 20deg C.......DEAD BATTERY OMG !
Fitting a new one tomorrow and will retest cold start and see what the voltage does this time . Am also taking it to Holden Dealer to get latest BCM flash so the charge routine is up to date! Explains a lot :)

[The Alchemist]

ok update on battery: al good now with correct charging and excellent starting now with 11.8V showing just after startup instead of about 11.2 and completely repeatable.
Update on B1650:
DON"T change this from standard as it seems to create a conflict with something else in the tables (maybe ones we can't see) and flags P0606 and reduced power mode in certain circumstances and driving conditions.
It does make the throttle open further which is great for cold starting and in gear stuff BUT this P0606 popped up as I was sitting there engine off but key on testing starting etc...I pumped the throttle to 100% somewhat absent mindidly and up came the ECL with this code....WTF !
I cleared the code and repeated this and it did it again !It also only reported about 36% tps even though I had my foot to the floor....stressing after reading what the code description said I did some research and came up with these links :

http://hsv-gts.ls2.com/0506GTODTC/DTC%20P060D.pdf
http://www.hptuners.com/forum/showthread.php?t=31670&page=2

all pointing to a conflict of some sort with the TAC ...
I decided to flash B1650 back to normal and retry this test. This time 100% throttle got the 88.2% TPS that I wanted :) and no fault code popping up ! Whew.
logs of fault and with it "fixed"
In the fault recorded one go right to the end to see it, I also logged GM.CPUFAULT as per Blacky's suggestion to get a special number that he can check..in this case "22".
I guess I'll find out what this means tomorrow.

[swingtan]

Seems a little strange as a few have altered that table with no issues.

The code you threw was a P0606, not a P060D, so some of the info is not quite right. Maybe there is another issue that is compounding the problem, possibly due to the relocation of the TB. It may be that the log data you have is actually showing the problem that is causing the code, not the result of the problem occuring?

Simon

[The Alchemist]

http://www.justanswer.com/uploads/SKeel1221/2009-05-22_215057_DTC_P0606.pdf
and this sorry Simon .....have a read.
This points to a TAC problem, but maybe the 36% throttle is a result of the reduced power mode kicking in though once it was triggered. Strange how the engine wasn't running and it triggered the moment I touched the throttle. Also the ECU voltage drops out to zero as I move the throttle but stops doing this after 3 tps movements...

[swingtan]

srry, double post.....

[hymey]

Thanks for the input Mike, what kind of pcv system do you have on the car? L98 valley cover style or LS3. You could go back to a L76 style and draw the air from the passenger side rear rocker cover thru a oil/air seperator with a one way valve(so it does not pressurise the engine). This will allow the engine to actually draw more air in thru the motor , I had my L98 setup like this when it was blown. I had to reduce min idle airflow to compensate for it quite a bit. The LS3 has the small restrictor which does not add much to airflow to the motor. Just a suggestion. I know some tuners alter B1650. I have never tried it my main concern was that it may not get full throttle?

Joel

[etmotorsports]

E38 Idle question, B1651 and B1652 those seem to be the max limit the ecm can open the throttle body at idle, but what does the area 1 and area 2 difference in tables is one in gear and the other park neutral? And in B1650 i have seen some stock tunes that use a larger area here i don't understand unless there was a larger throttle body?

[swingtan]

The way I read those is...


{B1651}: Maximum rolling idle area. IE. the maximum opening % that the ECM can command when the car is moving.
{B1652}: Maximum stationary idle area. IE. when the car is not moving at all.


{B1650} seems to let the ECM know how big the TB is, which is then used to help work out what amount of opening is required for a given air flow. It's not a hard and fast rule to match the actual WOT volume here, in fact some deliberately set this low to help with cammed cars. I've gone as far as setting this to 3600 with no adverse effects, but I'm not sure how far you can take it.

Simon

[etmotorsports]

Thank you swing it does not say in my efilive that good of a description about rolling and stationary, i kept moving min idle air and the tbody wasn't opening any more so i played with those tables and it opened more which really started to bring the idle up which is what i needed. But was un clear about idle or moving.

[swingtan]

Yes, it took a bit to work that out. I actually reduced {B1651} quite a lot, down to around 1% for testing. I found that when cold, the rolling idle would drop a lot, then pick up as the car stopped.

[etmotorsports]

Odd i increased the tables and still its hard to start cold takes a few tries but i haven't had much time to play with that while it was reduced the tbody wasn't open near enough to get the idle to the commanded

[swingtan]

As already mentioned, try....

Reducing: {B1650} and {B1701} by 20%

Increasing: {B1832} by 10%

Simon.

[ringram]

I did get an ETC code and have to adjust airflow vs tps or whatever table.
But I have many more cubes behind it. I definitely need B1650 otherwise things are bad with cold starts etc.

[The Alchemist]

12804

Hi guys , another cold start idle issue to address so I thought this would be the best place to post.
VE Holden L77 engine with AFM delete kit and a big LS3 cam 235+ duration 600 thou lift, full exhuast, FAST manifold etc etc. You know, one of those "just a tunes" :)

Problem: Cold start is fine (learnt a whole lot since my last posts on this topic !!! ) but the commanded AFR is 9.98:1 and commanded lambda 0.688 so the car runs very rich pulse width 6ms!! with horrible surging as a result. I'm running similar IVT open loop tables to other cammed VE's and have never seen this problem before.
At exactly 40seconds after 1st startup (done 4 cold starts logged and measured) the commanded AFR & Lambda suddenly jumps vertically to 12.8:1 & 0.881 respectively and the pulse width drops to 3.8ms and the car idles beautifully. At the change point the IVT is at 50deg and the ECT is at 35deg. I even dropped the IVT open loop B0146 table flat from 56deg backwards and it made no difference to commanded AFR/Lambda. It only occurs from dead cold, if you stop the engine just after the switch point and restart the commanded appears normal around 12.8:1. No other problems during warm up and the car runs great etc etc. One of the first things I did was check LTFT's which are turned off but these read "0" as I had done a fuel reset as a matter or course.
O/S 12647991 Calib 12647990 2012 VE Holden.
Any suggestions fellas? I'm really stuck here.....

[hymey]

Hi bud, I did a L77 lifter swap 236-242 cam 11.8:1 a few months back. I must admit I have never had this pulsewidth issue. I also am unsure how you setup the open loop tables are B0141-144 all the same? try setting them all to 1.00s if u havent done it and B0147 to 1.00 and just use B0146 to change commanded fueling if you have already done this just to test, use completely stock open loop tables. See how it responds then try using all 1.00s in B0146. To be honest this car has completely stock open loop tables and dynamics and cold start drivability is awesome, not to smelly at idle cold start either which is typical of more overlap and metal cats. As far as idle tuning I still do the same things and it still works I have tried other methods and had some good results but have all charts written up now and always get them close within a couple of flashes. Try and finess the VVE as much as you can i find if it is autocorrectly to many cells after you have made changes close the tune and reopen and then make changes try it and see what happens. I also built tuned a 408 and runs a 250s cam it runs like a baby dead cold certainly makes life a lot easier to drivability tune with a 4.00 inch crank in there.

[Chuck CoW]

12804

Hi guys , another cold start idle issue to address so I thought this would be the best place to post.
VE Holden L77 engine with AFM delete kit and a big LS3 cam 235+ duration 600 thou lift, full exhuast, FAST manifold etc etc. You know, one of those "just a tunes" :)

Problem: Cold start is fine (learnt a whole lot since my last posts on this topic !!! ) but the commanded AFR is 9.98:1 and commanded lambda 0.688 so the car runs very rich pulse width 6ms!! with horrible surging as a result. I'm running similar IVT open loop tables to other cammed VE's and have never seen this problem before.
At exactly 40seconds after 1st startup (done 4 cold starts logged and measured) the commanded AFR & Lambda suddenly jumps vertically to 12.8:1 & 0.881 respectively and the pulse width drops to 3.8ms and the car idles beautifully. At the change point the IVT is at 50deg and the ECT is at 35deg. I even dropped the IVT open loop B0146 table flat from 56deg backwards and it made no difference to commanded AFR/Lambda. It only occurs from dead cold, if you stop the engine just after the switch point and restart the commanded appears normal around 12.8:1. No other problems during warm up and the car runs great etc etc. One of the first things I did was check LTFT's which are turned off but these read "0" as I had done a fuel reset as a matter or course.
O/S 12647991 Calib 12647990 2012 VE Holden.
Any suggestions fellas? I'm really stuck here.....


Hmmmm.... It's interesting what you say about the 40 seconds.... Has anyone else seen the 40 seconds thing? I've always seen that

there IS some timer and there IS a noticeable change when that timer expires.... Can't quite put my finger on it, but I would love to

hear from anyone who has seen this or knows more about it.....

Chuck CoW

[The Alchemist]

yup thats exactly how I do it Hymey :) Its like theres and after start enrichment table that expires after 40 secs that we don't have access to????? will try setting B0146 all to "1" and see how she goes today. thanks for your support.

[The Alchemist]

1280712808

THIS IS THE COLD START , AND A DRIVE TO WORK, with b0146 set all to "1" as well as the b0147 b0148.
as you can see something is commanding 10.5:1 or 0.716 lambda for 40 sec after starting. Screen shot zoomed in on AFR and lambda. You can also see that for 15 sec after startup 3 small blips on the commanded AFR/Lambda.
ANy ideas about this?
Perhaps Ross may shed some light here for us > Ross?

cheers,
Mike

[The Alchemist]

EFILIVE had found the fix....an update will be posted shortly

[kangsta]

was it a newly uncovered table?

[The Alchemist]

yup it was, but its not "new" , just one that hasn't been used by GM calibrators in older calibrations. A explanation on said table/feature will follow in an update shortly as this table will affect cammed engines cold starts. Standard engines it has no effect so not to worry with those.....

[The Alchemist]

Next problem....."Fixing" a poor idle issue on a big cammed VE for a customer.Os: 12612381 Calib: 12612380
An early Model VE Holden.
The main culprit is that the biggest ECT TP it will command is 12.7% and thats it even with B1652 at 6 which maxes it out. This is in open loop idle tuning with Min idle airflow maxed out to 63g/s and intergral/proportional set to "0"
The VE 2012 model I've just finished tuning allows 18.8% with B1652 set to only "3" making cold starts a dream cos you CAN open the throttle further to get the airflow you need.
Surely there is a setting that can be made available that sets maximum throttle blade angle in idle mode. In earily calibrations this may be set much lower. I've followed exactly the same approach as I always have in setting up the idle.
My other question is: why does B1650 Max etc area change between models/years with the same throttle body attached to the engine??? I have tried changing this before to tweak max idle ECT TP but often get a limp mode fault P0606 ECU dead. Ringram you say you change B1650 with cammed cars. Could you please let us know how much you change it and what you have achieved using this approach. Changing this value though is surely a bandaid approach. I still think there is a setting for max allowed blade angle at idle because of the different max ECT TP at idle I'm seeing between different years of VE Holdens. Thanks.

[kangsta]

yup it was, but its not "new" , just one that hasn't been used by GM calibrators in older calibrations. A explanation on said table/feature will follow in an update shortly as this table will affect cammed engines cold starts. Standard engines it has no effect so not to worry with those.....

any updates on this?

[PRAY]

Prabably in this thread somewhere but does the same process apply for E67's?

[ringram]

Mine is 3300 or so. Ive not got the latest in front of me.
Im sure there is a missing table, but b1650 is the best value in lieu of the real table.
Jessie put me on to it when we were chatting at Sema. But it works. No holes need drilling etc. Im sure it does affect many other things, but idle transitions are pretty good, vastly improved over not changing b1650.
I wouldn't hesitate to change it.

[94SS]

Better logging is definitely needed. I am really suprised idle isn't a priority.

[The Alchemist]

any updates on this?


{B1219} Low Volatility Fuel Detect.

Turn to "off"

[Highlander]

Anyone got a good trick to get the car to be smooth from park to drive? This 2011 (never happened to me before) wants to die when I put it into park and reverse.

[Taz]

If you have upgraded the camshaft, odds are the problem is airflow related. Post the tune when you have a chance ... myself and / or others will take a look. Also, a log of the event occurring - including at least the following PIDs:

GM.AIRPERSEC
SAE.SPARKADV
GM.ETCTP
SAE.RPM
SAE.ECT
SAE.IAT
SAE.MAP
E38.INVLVTMP_DMA


Plus whichever gear position PID is supported for your OS.


Regards,
Taz

[swingtan]

In some OS's, there are "shift into gear" corrections for this (B1827}, {B1828}, {B1858}. Not all have these though.

If you don't have these, then you are stuch with getting minimum idle air spot on, or slightly high {B1829} and then use Idle Integral Step Size {B1844} to trim with.

Simon.

[Highlander]

I think the main problem comes from somewhere else. Voltage is a tad too low.
Engine will not let me take a log (ECM not detected) after the car has started. As long as its shut off it does.

Problem with a ground.. but... I didn't remove any grounds!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Naf]

How about a tune file, and a log includin your fuel trim. I am curious if you are able to give an open loop log with a WB readout...

[hymey]

Anyone got a good trick to get the car to be smooth from park to drive? This 2011 (never happened to me before) wants to die when I put it into park and reverse.

I have had this issue with t/m pulling airflow on shift, is it setup by throttle or timing and fuel in the A6????. I just improvised with it, I raised min timing at idle.. and played with some corrections. If I turned off t/m it fixed it right away but this car needed torque management. Also I reduced B1650 something to keep in mind and as the idle percentages were so high when it would go into the high timing table! then drop back to the idle timing tables and begin corrections again. This is something I found you have to watch for. Luis Sola told me about this some days before. I actually did not drill a hole in the TB in this car to begin with. But with this issue I drilled a 4 mm hole and reset up the airflow tables to suit(created a buffer).. then put B1650 back to stock. Car idled very nice and stable this also fixed the drop from drive then into reverse. There is no right or wrong way to do these but u have to do the basics first then improvise they are all different, and need to be assessed. Basically see what they respond too. B1652 was set around 0.5 above what it wanted at hot idle and B1651 set 0.15 below. I also raise min idle air below target idle speed then raise up slightly after. I adjust up and down at 1400-1800 rpm to get best throttle feel and smooth transition. Use the main tables to get it all squared away. If you dont want to drill holes. watch for the timing issue. I just keep doing what works for me and never lets me down. The combinations I build now run 260s plus duration and it does get harder here but I use the same principles. Some o/s react different to others .

[hymey]

Next problem....."Fixing" a poor idle issue on a big cammed VE for a customer.Os: 12612381 Calib: 12612380
An early Model VE Holden.
The main culprit is that the biggest ECT TP it will command is 12.7% and thats it even with B1652 at 6 which maxes it out. This is in open loop idle tuning with Min idle airflow maxed out to 63g/s and intergral/proportional set to "0"
The VE 2012 model I've just finished tuning allows 18.8% with B1652 set to only "3" making cold starts a dream cos you CAN open the throttle further to get the airflow you need.
Surely there is a setting that can be made available that sets maximum throttle blade angle in idle mode. In earily calibrations this may be set much lower. I've followed exactly the same approach as I always have in setting up the idle.
My other question is: why does B1650 Max etc area change between models/years with the same throttle body attached to the engine??? I have tried changing this before to tweak max idle ECT TP but often get a limp mode fault P0606 ECU dead. Ringram you say you change B1650 with cammed cars. Could you please let us know how much you change it and what you have achieved using this approach. Changing this value though is surely a bandaid approach. I still think there is a setting for max allowed blade angle at idle because of the different max ECT TP at idle I'm seeing between different years of VE Holdens. Thanks.

You have to be careful with b1650 some models all good others not I have messed with it when changing to 102mm throttle bodies in the past. Use a combination of hole and B1650. is best.Larger engines have higher airspeed. And need less throttle at idle same as FI engines. with the 6L they will need more idle air . The L98 6L. has a lazy port and requires more throttle openings. Some older os had a very low hard limit. But I think I may know what is causing the issue but I would have to look at the tune. How did u go with the rich start up?

[MarkR8]

Hello Hymey,
I have a problem and I can't work my head around it at the moment - need help
I had my car idling after following your steps minus the throttle blade drilling and I had an idle. Then once i drilled a 4mm hole I have no idle and it goes into protection mode showing P068 and P102 (car is in OL)
Tried increasing B1651/B1652 to 1.120 but still the same result.

I logged the idle prior to drilling the throttle blade and had the following:
Map -73
Airflow - 11.5
Spark - 5-15 but mostly avg of 8

Cam is 226/236 110 @ .525 and I have fitted LS3 heads on this LS2 and using the tune which was dialled in prior to the engine mods.
I am sure I can follow your steps once I rid myself of the engine protection problem but for the moment it has me miffed. Please help

[Tre-Cool]

is that manifold pressure at idle in gear? i've had much bigger cams and similar lsa idle in the 65kpa range with an 800rpm idle. you would be just about triggering pe mode with that idle map.

[MarkR8]

I had that map at idle (in neutral) see first log file. This is where the car idled somewhat albeit rich as it pulled idle spark down and this was also just prior to drilling the throttle butterfly.
Changed B0157 to 100Kpa and logged the following start-up - still went into engine protection mode.
I am sooo lost right now, all I see that might be wrong given all the conditions is the OL fault in the attached log but i'm still at a loss :(
I am confident this will work but seriously need help1349313494

[Naf]

First you shouldnt have drilled that hole, but here is how you fix it...

C0803, C0805, and C0806 need to be increased to compensate for the added airflow. You engine is tryin to protect itself from runnin away.

Now After you fix that, put your car in OL and tune you MAF from idle up to WOT, use the BEN factor Map in your scan software. Set your AFR and PE properly then adjust the MAF through the BEN factor in your Map options.

I set my Afr to 14.62 and PE to 12.5. I then adjusted the timin and ran the car.

I have found that if you Tune for AFR first then timing everything works out...

[Naf]

Just a little note,

If you have noticed that when you break the rpm drops below your recoomended amount no matter how high you set the min airflow. its because you need to increase B1602. Airflow correction based on coolant.

You will have to add small amounts stowly with two restarts inorder to get a proper reaction from the engine. I have added 0.135 to my whole table and as a result my loopie idle calmed down a little.

If you add too much you will feel the engine pull you in Drive a little too much. but with the right amount you should not see a drop in rpm below your desired amount...

Have fun and dont forget to tune you MAF properly

[ringram]

My B1650 is running just under 3000 and its also sorted idle transition dipping when coming to a stop.
Still no hole required.

[hymey]

From what I have found with larger ci through smaller TB is no hole is required . As airspeed is much higher. Though small cube 6L is different with large overlaps. Thats on my exp tuning a lot of e38s not just one car:)

[hymey]

They are airflow diagnostic faults .. You have to turn those off... I always drill holes. And I fix other tunes a lot , there is a lot of work to get them perfect once you get the hang of it no probs, just experience.There is a million ways to tune them I just have found they are all different and 99% of the time it is just 1 or 2 things that make a big difference. Last 5% is always hardest!

Go to the electronic throttle diagnostics and select 8000 rpm and 20 v then then other is a MAF fault(meant to be there). All mafless e38s will do this bolt on or cammed unless you turn those off.

Idle dipping has nothing to do with B1650.. That is min idle airflow and integral limits combined with proportion and integral values. Then coast down spark is a huge trap aswell. B1650 is only changing idle % and different airflow numbers. I very rarely change this , if it still hunts you need a buffer .

[ringram]

No need to disable DTC codes with B1650 either ;)

Each to their own mate. As long as it works.

Personally I prefer no hole and not having to disable DTC codes, but thats just me.

Im with you on the 5% being hardest. Also I was with you on the min idle airflow affecting idle dip, until after many many changes fixed it with b1650. Idle is rock solid, its transitioning back to idle where it dipped.

[AllOutPerformance]

I have a truck that ive done the step by step on and cannot get to stay running if you rev the engine.can anyone help

[swingtan]

Post the tune and a list of mods.

FWIW, I've been trying (and failing badly ) to get an L98 based stroker to idle for the past couple of weeks. I tried all my usual tricks and this thing was just a dog. It's idle fine just sitting stationary but as soon as is transitioned from driving to stopping at the lights, it'd surge and stall. I spent hours on this and was ready to blame the NW TB, until his mechanic decided to try a swap the Fast manifold and NW TB for stock items. When he removed the Fast, he found one split runner and numerous others that were loose and flopping about. Fortunately all the screws / bolts were accounted for so nothing went through the motor. With the stock manifold and TB on, it idled fine with no changes to the tune....

[AllOutPerformance]

swingman can you call me 559 999 2265

[AllOutPerformance]

combo 6.0 234 239 111 plus 3 cam fast intake long tubes i did the 4mm hole in tbody .2008 pickup 2631 os

[Naf]

I have a truck that ive done the step by step on and cannot get to stay running if you rev the engine.can anyone help

Please post your tune and i will have a look at it

[Naf]

Post the tune and a list of mods.

FWIW, I've been trying (and failing badly ) to get an L98 based stroker to idle for the past couple of weeks. I tried all my usual tricks and this thing was just a dog. It's idle fine just sitting stationary but as soon as is transitioned from driving to stopping at the lights, it'd surge and stall. I spent hours on this and was ready to blame the NW TB, until his mechanic decided to try a swap the Fast manifold and NW TB for stock items. When he removed the Fast, he found one split runner and numerous others that were loose and flopping about. Fortunately all the screws / bolts were accounted for so nothing went through the motor. With the stock manifold and TB on, it idled fine with no changes to the tune....


U may have to bump up the maf readin and increase the coast timin slightly

Please also post ur tune

[swingtan]

swingman can you call me 559 999 2265

I would, except I'm in Australia.....

Send me a PM and I'll give you my email address though.

Simon.

[swingtan]

U may have to bump up the maf readin and increase the coast timin slightly

Please also post ur tune

No need to look at the tune, the problem was with the Fast manifold, and it's a MAFless tune anyway.

Simon

[AllOutPerformance]

I would, except I'm in Australia.....

Send me a PM and I'll give you my email address though.

Simon.

pm is full bud my email address is elky489@yahoo.com ill send you the file

[AllOutPerformance]

i did pull the fast off right now and found some loose runners but none of them were really loose just a few turns of the torx

[PRAY]

Same thing just happened to me with a FAST 102/NW 100 combo. This thing ran like a dream for a couple days then the day of the dyno it crapped the bed on me as far as drivability. Tuned and tuned and got it to work for a couple days. Then it crapped out again. I had to be out of the country so the customer took it to three different well known shops after who tried to tune it and ended up with my tune over and over. Turned out to be the FAST was cracked behind the TB mounting nut. You can't tune that out. I have not been impressed with the FAST's as of late.

[AllOutPerformance]

Ok update after some help from a fellow forum member the idle was never right with the fast.we pulled fast off and loaded my earlier tune and bamm idled cherry.and only lost 8 whp.pickedup alittle tq to with stock intake.

[Naf]

No need to look at the tune, the problem was with the Fast manifold, and it's a MAFless tune anyway.

Simon

Ah, was it an air leak due to bad inner seal? I always take mine apart and give the inner a nice bead of silicone.

Why did you go MAFless? is it due to lack of space in front of the TB or for a few more ponies? I found my CTS ran better with my MAF than without it...102mm

[swingtan]

I'm not sure what is was, but there was a lot wrong. The car is actually on the other side of the country and I've been tuning it remotely.

It's MAFless for a number of reasons...


Nick Williams 102mm TB: Why go a bigger TB if the MAF is still only 90mm?
The OTR would result in a very tight fit for the MAF.
The MAF would be positioned directly in front of the TB. This tends to amplify cam pulsing being detected by the MAF, causing incorrect reading.
The customer wanted it tuned MAFless.


My car still runs the MAF, I don't really mind either way.

Simon.

[Naf]

I'm not sure what is was, but there was a lot wrong. The car is actually on the other side of the country and I've been tuning it remotely.

It's MAFless for a number of reasons...


Nick Williams 102mm TB: Why go a bigger TB if the MAF is still only 90mm?
The OTR would result in a very tight fit for the MAF.
The MAF would be positioned directly in front of the TB. This tends to amplify cam pulsing being detected by the MAF, causing incorrect reading.
The customer wanted it tuned MAFless.


My car still runs the MAF, I don't really mind either way.

Simon.

I agree the OTRCAI has the MAF too close to the TB and you would have to increase the MAF to 1000rpm and let it automatically adjust instead of using the MAF as a reference.

The 102 is a monster, have a 102mm intake with 102mm MAF and 102mm TB goin into a 105 FAST intake. Idle and low loads was a problem. Had to increase timin to the max to get me moving...

[Roonstain]

Sorry for the overly basic question, but how would one tune in a lumpier idle?
The car is already cammed and has been tuned with a fairly smooth idle

[Naf]

Sorry for the overly basic question, but how would one tune in a lumpier idle?
The car is already cammed and has been tuned with a fairly smooth idle

Drop ur idle timong by 2-4 degrees get it somewhere between 15-17 degrees of timing

[MarkR8]

Sorry for the overly basic question, but how would one tune in a lumpier idle?
The car is already cammed and has been tuned with a fairly smooth idle

To make it choppier you will need to reduce idle speed spark corrections and let the airflow corrections keep the desired idle speed. It will result in a choppier idle

[Roonstain]

Which tables in particular?

[MarkR8]

You need to reduce spark correction in B5128,B5129, B5130 and B5131 (I just use the same in B5128/B5130 and same in B5129/B5131)
Use B1844 ans B1845 to get the airflow corrections required.
Play around with those tables and you should get what you are after.

[MikeOD]

I went through this thread yesterday and tried to use the procedure posted by hymey all in search of a better (smoother) idle and maybe dial away some light throttle surging in my car...but I think I'm misunderstanding what everyone means when they say to watch the TB start trimming when I'm dialing in the min idle air. My car is a stock bottom end LS3 with ported heads, 226/234 .600/.600 114 cam ground with 4 degrees of advance, FAST 102mm manifold. I've played with the NW102mm TB, but I'm so tired of fighting surging at very light throttle around 1500 rpm, I'm doing everything I can to fix it...so I put the stock TB back on the car...I figure if I can make it right with the stock TB, then maybe I'll try putting the NW102 back on.

After that, I thought about it some more, and thought, why not use the same idea behind limiting B1651/B1652 to find values for B1829 as well. At first I maxed out B1829 and zero'd out the B1843 and B1845 (my car doesn't have B1844, but I think those were still the right tables, 2010 Camaro LS3/M6 12637084). I brought down B1651 and 1652 until I was able to get the engine to sit at 800 RPM and average 15 degrees of timing...I wound up with 0.8998 in both of them...which I thought was rather low...but it was working, with the correction tables zero'd out, timing was pretty solid and RPM was holding well too...but maybe I have a vacuum leak, I'll need to investigate that again this weekend, when I will remove the FAST 102 to check it out thoroughly.

Once I found those values, I saved them, and then maxed out B1651/B1652, and put 8 into B1829 (the whole table) and fired the engine up again, and again, I kept changing the number in B1829 until I sat at 800 RPM and ~15 degrees of timing as an average...I wound up with 7.52.

Does this seem like a logical approach?

After doing this, I put B1651/1652 back to 0.8998, then added 0.04, which resulted in setting them to 0.9398, then I took the value in 800 RPM for B1829 and multiplied it by 0.8 (maybe this was too large a change)?

I now put the OEM data back into B1843 and B1845, and then multiplied both tables by 0.5 (to try to make them less agressive), and the car started and idled on it's own...there was really no startup flare like I'm used to...in fact it seemed to be struggling to start...but the idle was great. When I revved it, it returned to 800 rpm beautifully from say a slow gentle rev to 4000 RPM, or a full throttle rev to 7000.

I drove the car home, and I still feel some surging around 1500 RPM...maybe it's a little better, maybe that's just me wanting to think it's better :(...either way, this morning I got in the car to go to work, and it was cold (45 F in the garage, compared to 65 F ambient yesterday when I was tuning, and the coolant temp when I was tuning was around 195-197) an it wouldn't start...it cranked, was very very lazy/sluggish to fire, and stalled immediately...I throttled it and was able to make it start, tried to back out of the throttle slowly to help it find idle, and it still stalled...I had to get to work so I yelled at the car, got in my other car and left.

Should I just try increasing B1651/B1652 to bring the cold start back, or should I try lowering B1650? I'm nervous to do that as I don't really understand what else it effects...I know that B1651/B1652 is the only MAJOR change I wound up making in the tune (my minimum idle airflow looks a lot like it used to) that seems to have killed the cold start...but what I've read makes me think that raising it back up too much will make the car surge worse at light throttle/low RPM. Stock B1651/B1652 were both set to 2.0645, and I'm way down at 0.9398...maybe I should try 1.25 or 1.375?

I'm going to go home at lunch time in an hour and get the car (I don't live THAT far away, and I HATE my other car, especially on nice days lol)...I guess I'll try 1.25 first and see if it starts on it's own...it's not as cold as it was at 7 am, but it should still give me a better idea.

I'd appreciate any insight/thoughts from others...I've been tuning for YEARS on older cars (old LT1's, LS1's, even older GM TBI stuff) and these DBW cars make me feel like it's my first day.

[MikeOD]

I brought the B1651/1652 values up to 1.5 and the car started...poorly but it started...stinks like fuel when it's trying to crank...never had that problem before. :(

I'm lost.

[swingtan]

My quick and simple method....

With the FAST 102: Check all components, especially the runners. They have been known to come loose and you will never get it to idle in this case.

With the NW 102mm TB: Just remember that the ECM calculates the effective TB area and uses that to work out how much the TB needs to move for a given gm/Sec correction. With the NW, it is significantly bigger than the 90mm stock unit. {B1650} and/or {B1701} may need adjusting for this TB.

The rest of the idle tables I'd set to stock to begin with and do the following.


Set idle speed to say 900RPM. Something fast enough to ensure it doesn't stall.
Set {B1892} up around 9.0gm/Sec, better too much than too little.
Bring the car up to normal operating temp and let it idle for a bit. Log the idle for a few minutes making sure exhaust airflow gm/Sec, AFR, timing, RPM, MAP, commanded spark and ETCTP are logged.
Check the log and highlight the idle section, note the average spark timing and compare with the tune setting for idle spark. If the average spark timing is over the tune setting, then you need to add to {B1892}. If the average logged spark timing is under the tune setting, you need to reduce {B1892}. Don't worry about surge etc. yet, just get the average airflow right. Your 15' timing should be OK for this.
Once the average timing is pretty close (within 0.5' of the tune setting) you can work on any surge.
With {B1845} I'd zero out all cells from -96rpm to 96rpm, then select the -128RPM row and hit "smooth" a couple of times. Do the same for the 128RPM row.
Use the Scan Tool DVT's to clear the learnt idle settings.


That's how I normally do it and it seems to work pretty well.

Here's a 408 stroker motor that would be similar to yours. This log it's idling on 900, but it can idle fine on 825.

15895

If you get into too much trouble post the tune and I'll have a look.

Simon.

[MikeOD]

Yeah, that's my plan for the weekend with the 102...I'll pull it off and check it out. It's all hand ported, to match my heads, but when I reassembled it I did use blue thread locker on the screws for the runners...we'll see I guess.

I've found with the 102mm TB on there, I HAVE to use 13 degrees of idle timing, can't run 15 degrees with that as that TB can't seem to close enough to bring the idle down with any additional timing.

I'll see what I find...it's a work in progress. I upped B1651/1652 to 1.625 for now, and I also took 4% out of the cranking fuel EQ ratio table, and it's a good deal better about startup...I was actually pretty happy driving the car to work this morning. I would like to put the big TB back on...I don't think I gained much power with it, but it looks so nice with that manifold. When I previously had it on there, I ran B1650 higher (I increased it until I didn't need to change the minimum idle airflow numbers to idle the way the stock 90mm did)...but I took it off for now just to try to wrap my head around this better.

Do you guys have trouble holding the engine just off idle with the pedal? Even with the stock 90mm on there, I can't seem to just hold the engine at say 1300 or 1500 RPM revving free in neutral. It's either up to 2000 or idling...kinda a pain, and I think is part of why I feel surges in gear at 1500 rpm at very light throttle.

[swingtan]

For the NW TB...

Setting {B1650} sounds like you had it close. For cammed cars I normally make this smaller with the stock TB but as the NW is bigger, I'd set this higher. Note that altering this setting may alter the behavior of {B1829} "Minimum Idle Airflow". You may need to alter {B1829} in line with {B1650}.

Set {B1701} to just under max, this would normally go to 8191.9 so set it to 8190. There are times when setting some cells to max, they get detected as out of range. So I usually set them to just under max.

Then try dropping {B2805}, {B2806} & {B2807} by 10%

{B1651} & {B1652} "should" be over 2.5%, I'm currently on 4.5%. These are simply a soft limit on how much correction is needed to control the idle. They don't actually do any adjustment themselves. If you had these very low (under 1%) and the car wouldn't idle when hot, then I'd say you didn't have enough idle air. Having these set too low would normally result in very poor idle when cold as the ECM can't command enough airflow.

As for the last point, that sounds like Throttle Follower. You can zero out the tables to prevent any follower from occurring. Surging is normally a combination of airflow correction and fueling. Low speed and light throttle put the engine in a condition where small adjustments on the throttle cause large changes in airflow, so lots of things come into play.

Post a log and the tune.....


Simon.

[MikeOD]

I zero'd out the throttle follower this morning before work and I'm pleased...I need to learn how to drive the car again lol...I actually have to use the gas pedal to rev the engine to start from a stop :). Before I'd breath on it, and have to get out of the clutch fast or risk sounding like a teenager driving a fox body. Now I can just tip into the throttle and come out of the clutch and the car pulls away smoothly (gotta love that Exedy twin disc, makes a little noise, but it's smooth as glass as long as it's not REALLY hot).

I forgot I had already lowered B2805/6/7 a while back by quite a bit, and it calmed a lot of the surge down. I had previously pulled some timing out of everywhere to try to combat the throttle follower problem...I bet that giving it back now that I've got those tables lowered will help the surge more too...forgot all about that.:doh2:

I'm not going to change anything else until I take the FAST 102 off and apart and make sure it's all ok internally...then I guess I'll decide where to go next. After that if I'm still having issues I'll post a log.

[swingtan]

Sounds like you're getting there then.

Simon.

[Yasei]

Does B1602 affect Cranking Idle Air (B1832) as well? Or does it only affect the Minimum Idle Airflow (B1829)?

[The Alchemist]

what timing do you have during the surging at light load, one thing I have found makes a MASSIVE difference to light load surge is timing. I call it tuning for driving around the supermarket car park :) with a cammed car you need way more timing than you'd think to achieve smooth progression at light load. Most tunes will run around 25deg at 1200 to 1500rpm, you actually need around 35 to 38 deg just in that light load area. Try it and you;ll find its a different car mate. Hope this helps :)

[Webbs]

Ok so I have been working on this process for a few days now and I think I am starting to get this beast of a car to play nice. I have a 417ci LS3 with a supercharger and supporting mods. My AFR at idle is 14.
5-14.8 my, VVE and MAF are both done just working out this blasted idle. Currently I am running 15*, 11 g/s in B1829, 1.7 B1651/B1652 and with a commanded 900rpm idle it idles rather nice in gear or park. Put it in Reverse or any forward gear and the ETC jumps from 17/18 to 23/24 and the timing drops into the negatives like it's trying to compensate for the increased air flow from the change in throttle angle. If I drop B1652 to 1.5 this condition is much better but not great. One last detail is that the g/s in my data log is 18 at idle and 23+ in gear. So is B1651 in park and B1652 in gear or are the blended to reach a sum total? Am I going about this the correct way or is my logic flawed?

W~


1634316344

[Webbs]

Here is one that has been keeping me up at night!!

I am commanding 11 g/s in B1829 and I can take B1651/B1652 from 1.7 to 2.5 and I get the same idle at 1000 rpm and I'm logging 20 g/s in my data log. Where is the extra 9 g/s coming from? I have more then enough head room in B1651/B1652 to let it run on B1829 but its not?

W~

[joecar]

I'm looking thru your files, but I can't see what is causing the 9 g/s difference.

[The Alchemist]

Just reading through a few old posts in here and found this one I posted:
"Next problem....."Fixing" a poor idle issue on a big cammed VE for a customer.Os: 12612381 Calib: 12612380
An early Model VE Holden.
The main culprit is that the biggest ECT TP it will command is 12.7% and thats it even with B1652 at 6 which maxes it out. This is in open loop idle tuning with Min idle airflow maxed out to 63g/s and intergral/proportional set to "0"
The VE 2012 model I've just finished tuning allows 18.8% with B1652 set to only "3" making cold starts a dream cos you CAN open the throttle further to get the airflow you need.
Surely there is a setting that can be made available that sets maximum throttle blade angle in idle mode. In earily calibrations this may be set much lower. I've followed exactly the same approach as I always have in setting up the idle."

Ross did you ever get a chance to have a look at this?> it would save all the "hole drilling" you have to do on the older VE Holdens?

thanks,
Mike

[HiPower]

1739517396 Can anyone help me out and peek and my logs and cal? Im running a cammed ls3 232/238 111 LSA. First time idle tuning. So far I got the idle stabilized. Although, sometimes start-up with the A/C will cause it to die. Also, timing isnt where i want it to be. Its adding a little bit more than i commanded. My goal is to get a steady lope.

[Naf]

1739517396 Can anyone help me out and peek and my logs and cal? Im running a cammed ls3 232/238 111 LSA. First time idle tuning. So far I got the idle stabilized. Although, sometimes start-up with the A/C will cause it to die. Also, timing isnt where i want it to be. Its adding a little bit more than i commanded. My goal is to get a steady lope.

May i have a *.tun file. Its when you save your tune on your laptop not device...

[Naf]

Ok, this is what i found,

Return B1845 and 1843 back to stock, then try it with this tune...

I bumped up your idle timing slightly as well are you min air flow

I have a 229/242 with a 114 lsa and found when a cam is that big it likes more timing and air flow.

[JohnPShoe]

I have gone through the tutorial and have made great progress, but i cannot seem to get it perfect. Are you still looking at tunes and helping to diagnose? I'm not sure how to PM within this forum, so I am making this post. Thanks in advance!

[joecar]

( you need to make at least 10 posts before you can send a pm... also make sure you enable Receiving PM's in your settings ).

[hymey]

I apologise for not being on here of late have had some health issues. My new email address is princeperformance@live.com.au . I check emails daily .

Kind Regards

Hymey