Going lean on tip in..

[MadMaxHSV]

Anyone know if there are any settings for tip-in or the like on the E40.
Logs are showing it running very lean momentarily on tip-in. I've seen the thread on transient fuelling adjustments but the tables mentioned don't seem to feature on the E40 OS.

It settles itself out but seems to be causing some hesitation especially when closed loop as it overcompensates.

Many thanks

[swingtan]

Post the tune and a log.

[MadMaxHSV]

Based on this response I guess there is no tables for adjusting transients, but here's the current tune and a related log anway

90639064

Tune is still work in progress.

Around frame 250 of the log you can see it spiking very lean with an increase of throttle before coming back down again.

[izaks]

B0199

[swingtan]

Is this thing running stock injectors? the VE looks rather strange and I'm wondering if higher flowing injectors have been used but the injector tables have been left stock.

[MadMaxHSV]

No, running 60lb injectors.
I had to tweak a few modifiers to get the values right as the flow rate values don't fit in the standard limits of the table.

VE shape looks ok (supercharged), although the boost VE looks a bit like a cliff-face at the moment. I'm checking to see if i'm running out of fuel pressure or whether this is normal... (but thats another matter)

The spikes i'm seeing are within the realms of the normal VE table so don't see it being here.

B0199 table could be it, will try increasing the values here and see if it compensates better.

[swingtan]

I'm going to guess that you are seeing the old "minimum injector pulse limit" issue. You normal VE looks very weird in the low MAP region, almost like the injectors are flowing much more that the ECM thinks. To fix this, the VE is very low in these cells. This could be causing the lean spikes as the ECM is pulling so much fuel in the low MAP area's that it "misses" the throttle opening and results in a lean spike. Your "normal" VE table peaks at under 43%, which is saying that your engine is less than 43% efficient, your MAF tables also look to be 50% down on the stock values.

All this suggests that you have altered all the tables to try and get the 60lb injectors to work, which may be a problem. I've heard of a few people having these sorts of troubles when going to larger injectors that the OS doesn't support easily. Because the airflow tables have been dropped so much, I'd start with...

B0184: Set the first 2 cells to 2,

Actually, to start with, I'd try and put the correct Injector flow rates in and re-do the entire VE table process. Others have already gone through this already and might have better ways of doing it, But I'd try doing this.... ( note that I have no idea how much has been modified and how much is stock, It might have been a bit dodgy direct from the factory..... )


{B4001} Add 54% to all cells. This will take the maximum flow rate to 8gm/Sec or 60lb/Min. It's probably still not ideal, but it's a lot closer than you currently have.
{B1213} reset to "1" to start with as this is also telling the ECM that the injectors flow less than they really do. Once things get better, revisit this to correct for any IAT drift in fueling.
{B1214} If you really want to try and get the injector flows spot on, you might want to try setting the voltage correction to skew the injector opening and correct for the additional fuel capacity. I'm not sure how well this would work though.
{B0200} and {A001} Return them to stock, or if they are still close to the original values, use a stock 2006 HSV tune and copy {B0200}. Then "guesstimate" {A0001} from the stock HSV VE table. ( actually, you may be able to use the DOD table in your tune )
Return all dynamics tables to stock.
{B1098} & {B1099} Return them to stock, or if they are stock, use the 2006 HSV tables.
Redo the VE and MAF tuning as per normal.


I get the feeling tough, that this tune is possibly a "Vauxhaul" special for the blown cars they released over there. It would be good to compared the original stock tune to see how it looked from the factory.

Simon.

[nevinsb]

I had that same goofy spike in the VE table in the corner when I had my minimum injector pulse width (And AIT compensation) set incorrectly as well.

Which injectors do you have? I got some specs for the Siemens shorty if you need some more information.

[MadMaxHSV]

Thanks for the pointers Simon,
gonna give this a go. I have the Greg Banish injector values which didn't fit in the B4001 table limits so I initially set them to half value with a multiplier of 2 in the B1213.
I haven't been using the MAF, but due to some early issues with 'reduced power mode', I halved the MAF tables also to match.
It was perhaps me following the 2 BAR COS tutorial too literally I think, that when I setup the boost VE according to the guide, the values hit the limit of the VE tables towards high boost.
To bring the values back into range I halved all the VE tables and changed the B1213 back to 1 to compensate. I think to get it running quickly initially I ended up with a value of 0.8 which I since skewed to compensate for IAT variations in fuelling.
Up until now all of this has seemed to work ok, albeit giving some odd looking tables.

But I can see this is potentially causing issues elsewhere.

@nevinsb. Have you got any injector values for the 60lb siemens shortys, that fit with the EFI Live tables?

Many thanks guys

[nevinsb]

Wow, didn't know your PCM could only handle 8g/s. Umm, mine can do like 512g/s.

What base fuel pressure are you running?

[MadMaxHSV]

Pretty good huh....

So the way I see it, there is no way to input the correct values for the base flow rate. I can scale to the nearest multiplier to get as close as possible but will need to multiply it up again with one of the modifier tables.

[MadMaxHSV]

Had a dud fuel pressure sender so intial pressure setup was out by 1 Bar. Currently at 5 Bar but will set back to stock 4 bar if I go back to starting from a clean slate with these tables.

[swingtan]

Yes, The maximum flow rate in the early E38's and the E40's is limited to 8gm/sec ( 60lb/Min ). So there is always going to be a problem with getting everything to work correctly. The big issue is that everything is linked to everything..... so the 50% trick causes big problems elsewhere. You may get away with doing this on a pure track car, but in a daily driver, there are other things to think about. For example, halving the IBFR will result in...


The VE needing to be more than haved to get the "correct" exhaust AFR's.
This then upsets the main spark tables, as the ECM thinks you have half the air flow you are capable of.
This reduces the granularity of the the spark control as the "gm/Cyl" values will be half of what they should be.
The reduced VE will result in the ECM calculating that the engine is producing much less torque that it really is. So torque control is reduced and auto shifting may be adversely affected.
Other modules require the correct settings to give valid data. The trip computer will probably be off when checking fuel usage.


My preference is always to get the major control points to where they "really should be" and then if I really have to fudge tables, do it in the lesser tables. Any table that controls base elements like air flow and fuel delivery really need to be as spot on as possible. In the case of the 60lb injectors though, you may not actually get the correct values into the flow table. So some compromises are needed here. the other thing is that I think the 8gm/Sec is a hard limit in the OS, so you can't fudge the flow rate to ever be over that setting. So if the real injector flow rate is still over the maximum values of {B4001}, you "might" be able to work out the difference factor, and then reduce {B0104} by that amount. This should leave the VE with realistic values, but will still impact torque calculations, though not as much.

Finally, for the reduced power mode, look under <Engine Diagnostics> -<Electronic Throttle>. The settings under there should help.

Simon.

[MadMaxHSV]

Very good points.
Hadn't thought about the effect on the spark table, the MPG dash readout is off for sure.
Right, will work on getting the VE back to normal levels.

Have never come across B0104 being used before (cylinder volume).
Are you saying to reduce the volume to reduce the fuelling?

Is there any of these knock-on effects with just using B1213 or B1213?

The reduced power problem I have relates to how the engine runs when in reduced power mode (or doesn't). I figured maybe it was defaulting back to using the MAF somehow so thats why I tried changing the MAF table. (didn't work). For now i'm not hitting it but wanted to try and sort it in case (engine dying at speed on the motorway not too clever)

[swingtan]

Reducing B0104 will make the ECM think it has a smaller motor, so if you have injectors that are flowing more than they should, the VE will end up being about "normal". The ECM will calculate that there is less air flowing in the motor than there realy is, so it commands less fuel, but as the injectors flow more, it all averages out. It will still impact the spark table, to to much less an extent than the current settings ( also remember that with FI, you probably can exceed the spark tables anyway, so a little bit of a reduction is OK). It will also effect the calculated torque etc, but again less than now.

RE: Reduced power mode, check the DTC's and see which one has been triggered. Normally it's the ETC rationality tests that trip, due to the airflow exceeding the expected levels. Quite often it triggers on throttle close as well. Check {C0803} through {C0806}, compare with your log data and adjust as required. this shoud stop the reduced power mode.

Simon.

[MadMaxHSV]

Ok, makes sense on the B0104

Would B1213 or B1213 make better sense not to effect any airflow/mass calcs?

I've stopped reduced power mode ok. Was just curious to see why when triggered it stops the engine from even idling. :)

[swingtan]

{B1213} should be used to fine tune the fueling in SD mode, for changes in the IAT. It can be used to tweak the flow rates,but as mentioned previously, I think the 8gm/Sec is a hard limit in the OS, so you can only use this table to increase the flow rates up to 8gm/Sec. This goes for all the injector correction tables, once the final flow rate reaches 8gm/Sec, you can't go any further. So the only real option is to "fudge" the air flow, which isn't ideal but should work. by setting the injector flow rate to as close as possible to the correct values, you should need to fudge the other tables less.

Simon.

[MadMaxHSV]

Ok made some progress.

"once the final flow rate reaches 8gm/Sec, you can't go any further" -swingtan

The above doesn't seem to be true.

I've corrected my tune with the original VE's, a guess starter boost VE, and returned to MAF operation.
The injector values were set to as close as possible within the table limits, then the correction factor put into the IAT correction table (with my original worked out temp correction slope). This technically should have put the final result above the 8gm/sec limit.

Fired her up. Perfect AFR. Put a few runs in and all seems pretty good. Picked up some sporadic knock (no more than 0.4 of a degree), but its using all of the Spark table now. Thinking this may be a mix of too much timing in some areas but potentially a symptom of too hot plugs (still TR5's) under sustained load.

Unfortunately my MPG reading is probably more accurate :(

So injector values are looking much better, thanks for the advice there.

I am now tripping DTC codes P0121 and P1101 at higher throttle positions. Could this just be that the VE is not matching the MAF output?

I'd got my heade so stuck in SD AutoVE, that I could have had it running this well just on the MAF until now. Anyway hopefully the AutoVE process may make work out better now.
Throttle response is definately down compared to the SD tune so that will have to be sorted out.

New tune and log attached for reference

91469147

[swingtan]

Ok made some progress.

"once the final flow rate reaches 8gm/Sec, you can't go any further" -swingtan

The above doesn't seem to be true.

That comment was in regards to the ECM calculations. The ECM has a hard limit of 8gm/S (60lb/Hr) for calculating engine fueling. Later OS's in the E38 removed this limit but the early ones are stuck with it. The injectors can flow more than this, you just can't tell the ECM that that they do.



I've corrected my tune with the original VE's, a guess starter boost VE, and returned to MAF operation.
The injector values were set to as close as possible within the table limits, then the correction factor put into the IAT correction table (with my original worked out temp correction slope). This technically should have put the final result above the 8gm/sec limit.

Fired her up. Perfect AFR. Put a few runs in and all seems pretty good. Picked up some sporadic knock (no more than 0.4 of a degree), but its using all of the Spark table now. Thinking this may be a mix of too much timing in some areas but potentially a symptom of too hot plugs (still TR5's) under sustained load.

Excellent work on the fueling, it looks pretty good. It would be good to get the IBPW logged as well, so some "reverse" calculations could be made to see if the ECM calulated flow rate really has gone over 8gm/s. My understanding has always been that it's a hard limit, but I've never had a car to test with. Your method of using the IAT table to "bump" the flow rates is how I would have tested it though, so it may be a good fix.

I'd certainly get some TR-6 plugs though. As you have mentioned, the TR-5's are probably a bit hot for the engine now.



Unfortunately my MPG reading is probably more accurate :(

So injector values are looking much better, thanks for the advice there.

Yes, getting the ECM flow rates correct will bring the trip computer back toward being correct. Run a couple of tanks through it and see if the trip computer readings are close to the real work figures. This will help confirm if the injector flow rates are close. I'm glad it's coming together ( probably not as glad as you though ). I know how frustrating it can get when something just doesn't seem to respond the way you thought it should.




I am now tripping DTC codes P0121 and P1101 at higher throttle positions. Could this just be that the VE is not matching the MAF output?

I'd got my heade so stuck in SD AutoVE, that I could have had it running this well just on the MAF until now. Anyway hopefully the AutoVE process may make work out better now.
Throttle response is definately down compared to the SD tune so that will have to be sorted out.

New tune and log attached for reference


P0121: Throttle Position Sensor/ Switch A Circuit Range/ Performance Problem see here for a very good description. http://www.ls2.com/boggs/dtcs/DTC%20P0121.htm

P1101: Intake Airflow System Performance. There are some reports of some GM calibrations having this "feature" and were fixed with a revised OS from GM. However I'm going to guess that you are throwing codes still because of the FI fitted to the car. So I'd try...

{B2007}: Set 0RPM to 50gm/S and 3000 and above to 400gm/S. then linear fill from 0-3000. These may not be quite right, but your log only has around 60% throttle peaks, so I'm guessing a bit.

This may help, but given the TPS fault, the P1101 may be related to that as well.

Throttle response will should be no different, unless other factors are coming in to play. You will need to do a full VE calibration to get it right, then dial in the MAF. Once that is done, you can start looking at dynamics which will really make the difference in a manual.

Simon.