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SSpdDmon
February 26th, 2007, 03:56 AM
I posted this over at LS1Tech.com. But just incase someone searches for info here, I thought I'd post up.

Someone PM'd me and I thought I'd share results...


hey man,i have a couple q's that i hope you can help me with.i still haven't got the idle right...when i hit the throttle it almost dies or does die when it comes back down because it drops so fast. this tuning is much more difficult than i thought it would be,plus i'm a tard :bang: any help greatly apreciated.
thanks

I found the problem with my car finding idle (coming down too far) after I rev'd it was fixed by doing the following:

*Note - The following worked for my '01 F-body M6 (232/238 cam w/ P&P'd 241's) after starting from the stock/default factory tables. Your car may require different changes. This is merely to help you find the right direction if you're still experiencing issues.

Adjusted Desired Idle Airflow. Log your STIT's and LTIT's to perform the RAFIG process (http://forum.efilive.com/showthread.php?t=5866&highlight=RAFIG). You want to get this close. But, don't sweat the details. It will never be perfect as desired idle airflow will fluctuate day to day. **Remember - logging the RAFIG is a correction. Values are added to the Desired Airflow table.**

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/desired-idle-airflow.jpg

Changed Airflow Learning Control Delay from 1.3 seconds to 4.3 seconds. What I noticed happening was it was taking more than 1.3 seconds for the idle to come back down when I rev'd it up...even without it hanging or coming down too slow. The PCM would then start correcting the 'learned' desired idle airflow with the STIT's and reducing the learned values too much. This would drop the idle down too far and the other correcting factors had to make up the difference, which would cause huge swings in idle. **Pre-'01 f-bodies only have one, combined delay timer. If you have a pre-01 f-body, you may have to work around this issue (i.e. don't change it) or upgrade to a newer OS.**

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/idle-parameters.jpg

Changed the Learned Airflow Correction table by zeroing out the 0-20 absolute rpm cells. This means the car won't correct the learned airflow values (STITs/LTITs) until it's more than 20 rpms above/below desired idle speeds. With cam'd cars that have a choppier idle, the STIT/LTIT settings can be too aggressive. This softens them up a little. I also tweaked the remainder of the table to make the Low RPM learning a little more aggressive than the High RPM column. This allows the car to learn up faster than it will learn down.

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/learned-airflow.jpg

Changed the Direct Airflow Correction table for High and Low RPM scenarios (Drive, A/C on, etc.). IMO, this was also making very aggressive airflow corrections - pulling too much if the idle was high and adding too much when it was low. By zeroing out the 0-40rpm cells and reducing the remaining cells to start, I was able to prevent the idle from over-correcting and swinging up & down. The "low idle" cells shouldn't require major changes - maybe 10~20% reductions to start if they are overcompensating. However, I suggest severly reducing the "high idle" cells by 50+% for two reasons: 1-Your RAFIG should be tuned and too much airflow shouldn't be an issue. 2-The Learned Airflow Correction Table will learn down the idle trims if desired idle airflow is too high due to environmental changes. Therefore, this becomes a stall saver for when the car isn't moving (or wherever your idle learning thresholds are set). THIS TABLE ALONG WITH THE DELAY TIMERS ABOVE HAD THE LARGEST EFFECT ON FIXING MY IDLE SWING PROBLEM. IF YOU'RE LOOKING FOR A PLACE TO START, START WITH THESE.

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/direct-airflow.jpg

Increased the Startup Friction Airflow Correction table for better starts. Although this doesn't really have to do with idle swing, I thought I'd include it because it seems to be a common problem. I increased this table significantly across the board to start. Pin-pointing by ECT, you can add a little in more or take out a bit where needed to ensure the car doesn't fall on it's face or go hog wild after a warm start. Now, my warm start issues are gone. It was stumbling right after startup, barely running because there wasn't enough initial airflow. Adding air in here is a good, temporary way to add in the airflow, which will be decayed out after the first 30 seconds or so.

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/startup-friction.jpg

Adjusted Throttle Follower Airflow Multiplier and its rate of decay. For light load, low RPM bucking, you can increase the multiplier to bump up the throttle follower airflow that is added. Remember, this is for surging while your foot is on the gas. If you have problems with surging off the throttle and believe it's airflow related, that's addressed in the throttle cracker tables. Keep in mind, when bumping up the multiplier, you need to increase the decay rate as well. If the decay is set too low, idle will hang up around 1200rpms or more until the follower fully decays out. I bumped up the multiplier to 3~5 depending on RPM (more down low) and increased the decay rates. Don't forget the P/N decay rates too. **This is working from an '01~'02 f-body throttle follower airflow table. Pre-'01 and C5 cars have different throttle follower settings. Copying all of the follower tables from an '01~'02 f-body tune may help as a starting point if using this tutorial.**

SEE POST #8 FOR SCREEN SHOTS

Changed the Idle Spark Overspeed/Underspeed Correctors. The stock settings are too aggressive in some areas and not enough in others IMO. I capped the swing to +/-9 degrees. Also, I brought up the underspeed spark correction for -200~-300 rpms. The stock table drops off...I changed those cells to 9 degrees. Just make sure this won't command too high of a spark based on how you have set the base spark and high/low octane tables. **A4 cars may have different spark settings. Ideally, you want to make sure that it doesn't go overboard with pulling timing for high idle scenarios OR it doesn't just quit adding timing if the RPMs drop 300rpm or more below target.**

SEE POST #8 FOR SCREEN SHOTS

Found the right commanded spark for idle. Right now, I'm commanding ~23* of timing at idle in my base spark tables (idle set at 850rpms when warm). The idea here was to find a good medium between what the car likes at idle and what it likes when first pulling away from a stand still (in my case <20*). The reason this is important is...the greater the jump from idle to non-idle spark, the more jerky the car may be while pulling away from a stop. What surprised me was the fact that the stock high/low timing tables were too high in the low rpm, low airflow portions of the table. I've included some pics of my base and high octane timing tables to show what is working for me. The key with the timing tables is to make sure you understand which timing tables are active depending upon your setup. Then, you can make the changes needed in the right tables (Base Spark vs. High/Low Octane). **A4 cars will require more base timing to idle for 'in gear', but similar base P/N and high octane/low octane timing tables should work. For base in gear, try 31* in the 800~1200rpm rows, 32* in the 1600rpm row, 34* in the 2000rpm row, and 35~36* in the rows below (for .28grams/cyl and less). You will also have to change B5916 (1.19%) and B5917 (255mph) to ensure you fall into the base timing tables when off the throttle.**

Another thing to note about timing - make sure you have your map enablers set appropriately. Knowing where the commanded timing is coming from (base vs. high/low) is key to getting the car to run the way you want it to. Personally, I like my car to be in the base timing tables anytime my foot is off the gas. Therefore, I set the MPH enabler to 255mph and the TP% enabler to 1.19%.

SEE POST #8 FOR SCREEN SHOTS

**Note - Since we're on the topic of surging...I used to believe more spark is the way to cure surging issues. However, I was wrong. Someone once stated that LS1's rarely require more than 40* of timing and surging issues can be cured with the IAC and the right timing. I currently have a max of ~35* timing in my base spark tables and high/low octane tables. My surging is virtually gone other than the occasional bump or two below 1200rpms. I guess they were right. Playing with the throttle cracker table and throttle cracker decay rate table were an important piece of the puzzle. Currently, my 1000 & 1600 rpm rows are zeroed out completely. I have 4 grams/second in the 400 rpm row to help prevent the revs from dropping too far when putting the clutch in or other similar scenarios (for M6 cars only). This combined with the timing adjustments sealed the deal with off throttle surging.

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/tc-airflow.jpg

Hopefully, these things are easy to find if you're using HPT. I know EFI Live has most of these tables under the Engine>Idle>Learning and Engine>Spark>Idle directories. Let me know how you do and best of luck!

neil
February 28th, 2007, 11:09 AM
Good writeup

Regards,
Neil

TAQuickness
February 28th, 2007, 11:39 AM
Very good info - Thanks for sharing.

joecar
February 28th, 2007, 11:52 AM
Tutorial material. :cheers:

dfe1
February 28th, 2007, 02:17 PM
Great write-up. For reference, when someone asks, "Will this work with ETC?", I've made similar mods to my C5 with 232/236 cam. I never had much of a problem with wild swings in idle speeds, but cleaning up many of the same tables improved idle quality smoothed transitions coming off idle. Low speed drivability is good enough that I can drive the car in 6th gear 1,000 rpm (with stock 3.42 rear).

Black02SS
February 28th, 2007, 02:20 PM
Awsome info!!

redhardsupra
February 28th, 2007, 02:22 PM
hey, let's combine forces and do a big update to my severly old, and in bad need for an update "idle tuning" writeup

SSpdDmon
February 28th, 2007, 02:29 PM
Thanks for the replies. Marcin, anytime...

**additional screen shots**

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/tf-multiplier.jpg

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/tf-decay.jpg

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/spark-overspeed.jpg

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/spark-underpeed.jpg

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/spark-base.jpg

http://i256.photobucket.com/albums/hh180/sspddmon/Tuning/spark-high.jpg

Redline Motorsports
March 7th, 2007, 03:33 PM
Tutorial material. :cheers:

I'll second that! This copying to my never ending word document that is 100 pages long is getting old! LOL!

Chad! pdf it!

HT

Black02SS
March 8th, 2007, 05:17 AM
Send me your word doc and I'll put it in PDF. :lol:

Black LS1 T/A
March 21st, 2007, 12:27 AM
Cool stuff! :)

Bruce Melton
March 21st, 2007, 02:52 AM
I would love it if we could expand this as many of us are converting to 90mm TBs and likely large cams which with ETC, is a whole new game.

SSpdDmon
March 21st, 2007, 04:32 AM
I would love it if we could expand this as many of us are converting to 90mm TBs and likely large cams which with ETC, is a whole new game.
The basics should still be the same.

**get the Desired Idle Airflow right with the RAFIG process
**timing should generally fall in the 24~32* range at idle for aftermarket cams (timing should be slightly more for auto's in gear vs. P/N)
**increase the delay timers for the IAC learning and direct airflow control
**work the throttle cracker/follower settings - I've recently noticed the throttle follower works better on my cam when I increased the airflow values (50% for the first 3.55% and 25% for the rest of the table) and increase the decay rates slightly so the revs won't hang on the way down. My throttle cracker settings are pretty much the same as when I created this post. Keep in mind though, the follower works a little differently on f-bodies vs. C5's. IIRC, I don't think the C5's used the follower multiplier table like the f-bodies do (ie C5 values are all 1's vs the f-bodies range of 1-3). So, there are some instances where an f-body will multiply it's throttle follower airflow values by 3 whereas the C5 is a direct pull from the airflow table. I'll check into this more later....

Bruce Melton
March 22nd, 2007, 03:54 AM
So far>
Seems with 90mm TB at least using stock .0255 and trying .0330 also .0157 as B4349, my stock desired airflow (B4307) is 7.3 G/S @80C and the logged RAFIG is < 1. So desired is ~7x actual, how to move it up?
The engine just dies when it reaches 178* when warming up. This coincides with going into closed loop.
I know I need more air but is "desiring" more in B4307 going to do it?

SSpdDmon
March 22nd, 2007, 04:18 AM
Desired Idle Airflow is the lookup table. As the ECT's change, the PCM looks to this table for the base idle airflow requirement (like it looks to the VE for fuel). It opens the elec. throttle body or IAC valve (depending on setup) according to that table. Then based on the idle learning tables and the delta between desired idle rpm and actual rpm, it adjust the TB or IAC through the idle trims. If it's wanting to die on you, I'd point to one of two things: either you're trying to get the car to idle at too low of an RPM for your setup OR the idle and learning tables aren't setup appropriately.

PM sent...

SSpdDmon
April 11th, 2007, 02:32 PM
Original post sync'd with current best tune.

hquick
April 28th, 2007, 10:17 PM
Hi guys,
I'm in the process of going through the AutoVE on my Whippled 98 (0411 pcm) Burb.
I logged RAFIG and the numbers are strange...although I don't know what's normal :Eyecrazy:
Do I need to get the AutoVE out of the way before doing the RAFIG, RAFPN process or can I do it now?
I have the VE table pretty well dialled in, I believe but the Burb is running extremely rich at idle. I can't figure out why.
Any advice/help would be greatly appreciated

SSpdDmon
May 1st, 2007, 12:48 PM
Well, running rich is going to affect idle quality. You want to try to get it close to an AFR in the 14's. What size injectors are you running? If they're bigger than 42's, you may have to futz with the injector tables to try and get your minimum pulse widths down.

hquick
May 1st, 2007, 12:51 PM
Thanks SS,
at present I'm running the standard 19pph, non-interchangeable injectors.
I realise OI may run out of fuel up top...but I would think idle should be OK with the stock tables?

redhardsupra
May 1st, 2007, 01:04 PM
AFR at idle is a strange subject. big cams are so inefficient in the idle range they usually cause a fake lean. i've seen some big cams which like to idle richer. one big cam would idle fine at 13.5AFR but would surge at both 13.4 and 13.6. there are no hard rules for it. try things, see what works.

SSpdDmon
May 27th, 2007, 05:30 AM
Write-up updated...

joecar
May 27th, 2007, 07:03 AM
Good work Jeff... :cheers:

SSpdDmon
May 27th, 2007, 10:34 AM
Good work Jeff... :cheers:
Thanks. I've learned a few things since the original write-up and now this thing is so smooth...I had to change my sig. :lol:

hquick
May 27th, 2007, 10:47 AM
Yeah...thanks.
It's guys like you that make this such a great place to be and tuning our cars so much more enjoyable!

DaddySS
June 16th, 2007, 09:47 PM
Yeah...thanks.
It's guys like you that make this such a great place to be and tuning our cars so much more enjoyable!

I'll second that!! Many thanks!:rockon:

Chalky
July 8th, 2007, 04:19 PM
Just wondering about cleaning up my idle and best way about doing it.

Rafig is close. Problem is car still has a lope and rough idle even with a 224/228 cam.

What is the best way to reduce fuel waste @ idle other than injector tables or is this the only solution?

SSpdDmon
July 8th, 2007, 11:48 PM
Just wondering about cleaning up my idle and best way about doing it.

Rafig is close. Problem is car still has a lope and rough idle even with a 224/228 cam.

What is the best way to reduce fuel waste @ idle other than injector tables or is this the only solution?
It's going to sound like it has a cam in it even with a 224/228. My friend's 224/224 cam had a nice choppy cam sound to it.

What's your desired idle rpm set at?

How much timing are you commanding in the base spark in gear table at idle?

What does your AFR look like (either WBO2 or fuel trims)?

Chalky
July 9th, 2007, 07:45 AM
It's going to sound like it has a cam in it even with a 224/228. My friend's 224/224 cam had a nice choppy cam sound to it.

What's your desired idle rpm set at?

How much timing are you commanding in the base spark in gear table at idle?

What does your AFR look like (either WBO2 or fuel trims)?

Idle is set @ 875.
Timing in Gear starts @ 27* @ starts to drop @ 40 grams/cyl

I have been in SD for some time but did go CL for a day and car was adding fuel. That kind of threw me but thought it might have something to do with my altering DFCO.

Car has red top 30# injectors with IFR's adjusted. Just wondering if the 30# injectors might still be commanded to much fuel even at the lower rpm.

SSpdDmon
July 9th, 2007, 09:04 AM
I'm battling my SVO 30's too. I'm finding that I'm having to alter the offset (voltage vs manvac) table because there's no other way to get the min pulse width down. I've tried skyrocketing the IFR table, dropping the VE table, dropping the min. commanded pulse widths, etc. with no luck. If I figure it out, I'll post up.

As for your timing, you've got too much. I'll shoot you back my timing tables when I get a minute this week. They should be a decent starting point for you. You may have to reduce 'em a little though with your CR being 11.5. If you did the RAFIG process and it's close, the idle shouldn't be too bad. Sent PM...

SSpdDmon
July 30th, 2007, 05:54 AM
Revised one last time...I'm a little bored today. http://www.motownmuscle.com/forums/images/smilies/lol.gif

Chalky
July 30th, 2007, 06:10 AM
Revised one last time...I'm a little bored today. http://www.motownmuscle.com/forums/images/smilies/lol.gif

And?

SSpdDmon
July 30th, 2007, 06:32 AM
And?
The throttle follower info was a little 'off', I added a few hints for the A4 guys after playing with my friend's car this weekend, and I posted new current pics of my timing maps. I'm going off of a modified version of distributor theory where you have timing that increases to a point and then is flat across the board....plus additional timing as vacuum increases. Hence the flatness of the timing maps. Seems to work great. Also found on my recent trip to the dyno that I didn't need the 28~29* of timing that I had at peak HP. 27* actually made more power. :D

Chalky
July 30th, 2007, 06:41 AM
Pretty stout cam you have. What is your static and DCR?

Can you post your latest timing table? Amatuer curiosity. I have mine bumped up to around 28* from about 5600 up.

Bruce Melton
July 30th, 2007, 06:42 AM
SSD,
I agree on the timing. I went with a LS7 with a biggish cam and had the same results as my car. Beyond 27, deminishing returns, 28 gave 4 more hp and 29 actually dropped from 27. All the runs were timing change only and the differences beyond 27 were really within deviation.
Chalky, if you start at 27* that is not good. I can give you a timing table to try.
Bruce

Chalky
July 30th, 2007, 06:46 AM
Bruce:

I knwo you had sent me a table some time ago for Tom. Go ahead and sent it out again if you don't mind.

FWIW, my timing caps @ 28* from 5600 and up. Never goes above 28*.:)

Chalky
July 30th, 2007, 06:56 AM
Pretty stout cam you have. What is your static and DCR?

Can you post your latest timing table? Amatuer curiosity. I have mine bumped up to around 28* from about 5600 up.

DUH. Just realized your notes were at beginning of thread.

SSpdDmon
July 30th, 2007, 07:12 AM
Pretty stout cam you have. What is your static and DCR?

Can you post your latest timing table? Amatuer curiosity. I have mine bumped up to around 28* from about 5600 up.

IMAGE REMOVED

That's the latest timing table for high/low octane. The numbers to the left (what you can't see) are all the same. Don't know about compression ratios though. :)

kostelacd69
September 9th, 2009, 06:45 AM
SS
if i post my tune and a log can you take a look at my tune. im having an issue with it idling up and down and not very smooth. ive got an 2001 silverado that has a 5.3 stock ls1 cam and 317 heads to get the compression down to 8.5. it drives good last week it made 502 hp at the tires. gas milage sucks but alwell. i read your post and just dont quite understand what im doing wrong. im new to the efi live stuff. if you could help me i can post what ever you need in a couple of hours. thanks david

kostelacd69
September 9th, 2009, 07:15 AM
this is the tune im having an idle issue with cant get it smooth the desired idle speeds are wrong they need to be 650 for the iac numbers just havent changed them back. it ilded fine untill i did the cos3 swap

SSpdDmon
September 9th, 2009, 09:21 AM
Why does your desired airflow table just drop off @ 176*F? If you don't have an aggressive cam, you shouldn't have to change too many idle parameters. I'd try putting everything in the idle folder (except desired airflow) back to stock and redo the RAFIG and RAFPN process. Make sure you go from a cold start and log all the way up to operating ECT temps (need to let it sit and idle for a few minutes once those temps are reached). I'm guessing your numbers need to be more fluent than they are.

kostelacd69
September 9th, 2009, 09:39 AM
im not sure what you mean with rafpn somethin air flow park neutal and in gear but what am i watching or log lbs/per min on the iac?

SSpdDmon
September 9th, 2009, 09:53 AM
im not sure what you mean with rafpn somethin air flow park neutal and in gear but what am i watching or log lbs/per min on the iac?
You need to log the idle trims (not fuel related). See this thread for detail:

http://forum.efilive.com/showthread.php?p=52291#post52291

kostelacd69
September 9th, 2009, 12:33 PM
here is my log and the average is .01. im lost you can see the idle going up and down

SSpdDmon
September 30th, 2009, 02:34 AM
here is my log and the average is .01. im lost you can see the idle going up and down
Sorry to respond so late - don't appear to have a subscription to this thread.

I couldn't view your log on this laptop (still on v7.4). So, I took a stab in the dark. The changes made can be found on the History tab right when you open the tune. Try out those new tables in your current tune and see if it's any better.

Just a word of caution. The timing values you have seem "different" to me. I don't know many setups that like that much timing in the low RPM, mid-low airflow regions....and with the idle over/underspeed timing controls limited to +/- 2*, that might be the cause of your idle swing issue. I primarily adjusted the IAC related tables that I thought would help improve your idle. But, you might want to consider reworking the timing settings you have.

joecar
August 16th, 2011, 02:14 AM
Related material that references this thread: Idle-Tips-amp-Tricks (http://forum.efilive.com/showthread.php?14439-Idle-Tips-amp-Tricks)



[ this is a note to myself as I organize stuff ]

Dewglass
February 1st, 2012, 01:08 PM
Related material that references this thread: Idle-Tips-amp-Tricks (http://forum.efilive.com/showthread.php?14439-Idle-Tips-amp-Tricks)

[ this is a note to myself as I organize stuff ]


Q:? Does MAF and SD use the same idle tuning methods in this thread?

joecar
February 2nd, 2012, 09:49 AM
MAF and VE have to be correct; then idle air has to be adjusted to match the actual air that is bypassed in the throttle body.

ecir45
March 24th, 2014, 03:44 AM
Created a pdf merging post 1 & 8 for this newb to follow.

joecar
March 24th, 2014, 01:27 PM
Good deal :cheers: thanks for posting.

Black LS1 T/A
March 25th, 2014, 11:07 PM
Created a pdf merging post 1 & 8 for this newb to follow.

This forum has always been a wonderful source of information. I hope to get my Trans Am back in a few weeks, with an all new LS7 engine, tricked out, and will definitely need an assist as this is a 1998 LS1 originally, and has been a challenge to modify.

Black LS1 T/A
November 26th, 2015, 03:48 AM
ttt

joecar
November 26th, 2015, 12:59 PM
tttBump.

voda1
September 5th, 2017, 08:54 AM
Photobucket delete on the maps on first page. Need updated.

pdf was made. see post #48