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Thread: Idle tuning

  1. #1
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    Idle tuning

    This was originally posted by Nogo a while back on LS1tech

    Here are some things you can try.



    Idle Limiters --> Idle Speed: 950

    Idle Limiters --> IAC Park Position: Raise all points from 40C and up to 21

    Idle Limiters --> Idle Air In Gear: All points 60C and up to 8.6

    Fuel --> Main VE Table: Multiply column 400 rpm by .60. Multiply column 800 by .80. Multiply column 1200 by .90.

    Ignition --> High Octane Table: Add 2 deg to all points 400 to 1000 RPM, .08 to .32 g/sec



    Once done with this program, start the car and check for surging. If the car surges, unplug the IAC and see if the surging stops. If the surging stops follow below.



    Idle Limiters --> Idle Air in Gear --> All points above 60C to 9.2



    Take the car for a drive and check your idle. If the car goes on cruise control reduce the Idle Air in Gear Table .2 (further if necessary). If the idle holds at 2000 RPM for extended periods of time reduce the P/N Airflow Decay table for all points above 10 MPH by 5% (multiply by 95) until this stops. Be vary careful on this table.



    If car keeps surging with the IAC unplugged two more things to try.

    Multiply Main VE table by another .95 (which would be a total reduction of 85%). Repeat until the surging goes away, or until the car begins to hesitate when you take off.

    High Octane Ignition Table. Reduce timing for all points 400 to 1000 RPM, .08 to .32 g/sec by 2. Repeat, but don't reduce it any more than 6 degrees.





    If your car still doesn't idle after this, then you have other problems, and should start looking elsewhere.

    Its not perfect & idle tuning is not always cut & dry but this has always been a very good starting point for idle tuning.

    Feel free to add you .02 as to what has worked best for you guys, but try and keep the thread on track with the same type of information.
    Last edited by Bill@HPTuners; 03-19-2007 at 01:24 PM.
    It doesn't have to be perfect, it just needs to be done in two weeks...

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  2. #2
    Senior Tuner Frost's Avatar
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    I actually copied the following correction from the same post on ls1tech. All of the theory is right here, I just don't want someone new getting hung up on the numbers thing:

    Quote Originally Posted by foff667
    originally posted by NoGo on ls1tech.com



    Here are some things you can try.


    .....
    Fuel --> Main VE Table: Multiply column 400 rpm by 60. Multiply column 800 by 80. Multiply column 1200 by 90.

    ...........
    Multiply Main VE table by another 95% (total reduction of 85%). Repeat until the surging goes away, or until the car begins to hesitate when you take off.
    ..........


    For anyone who is new and reading this, 60, 80, and 90 are percents (%)! Do NOT multiply your table by these numbers. You want to use 0.60, 0.80, and 0.90.

    In the second bit quoted, note that total reduction from stock should be 15%-ish at that point
    Steve Williams
    TunedbyFrost.com


  3. #3
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    corrected the first post to be a little more clear.
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

  4. #4
    Tuning Addict WS6FirebirdTA00's Avatar
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    There is no need to put the IAC park position airflow up that high, increasing the table by 2-3 is plenty.
    Sulski Performance Tuning
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  5. #5
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    This is a start with this & go from there guide. It doesnt mean put this there & not touch anything, but this guideline will get 99% of the heads/cam cars you'll see started & running. Using bi-directional controls or the idle mode of RTT is the best way to go around getting your base running airflow, idle rpm, & spark inline.
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

  6. #6
    Tuning Addict WS6FirebirdTA00's Avatar
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    yeah but from what I have seen, that park position airflow at 21 isn't going to help anything out. I have never done that (even on my first cam tune I did on my car). Maybe others have seen it actually prove to be useful, but I have not.
    Sulski Performance Tuning
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    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  7. #7
    Senior Tuner Russ K's Avatar
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    The IAC Park Postion should be left stock. It just determines where the IAC/Throttle blade is
    when the key is turned off.

    Alot of Nogo's methods are out dated.

    Russ Kemp

  8. #8
    Tuning Addict WS6FirebirdTA00's Avatar
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    Quote Originally Posted by Russ K
    The IAC Park Postion should be left stock. It just determines where the IAC/Throttle blade is
    when the key is turned off.

    Alot of Nogo's methods are out dated.

    Russ Kemp
    Exactly, and if anything should be done it should add to the frictional airflow table to aid in start ups.
    Sulski Performance Tuning
    2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  9. #9
    Senior Tuner Russ K's Avatar
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    Quote Originally Posted by WS6FirebirdTA00
    Exactly, and if anything should be done it should add to the frictional airflow table to aid in start ups.
    I leave the frictional table stock. For better start ups, I add ~2 g/sec airflow to the start up airflow table & set the delay to 100 camshaft revs.

    Russ Kemp

  10. #10
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    If they are outdated would you guys mind trying your hand at a sticky? You guys can just post whatever methods you use here as a starting point & I can delete the flim flam
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

  11. #11
    Tuning Addict WS6FirebirdTA00's Avatar
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    Quote Originally Posted by Russ K
    I leave the frictional table stock. For better start ups, I add ~2 g/sec airflow to the start up airflow table & set the delay to 100 camshaft revs.

    Russ Kemp
    I have tried that but I have had issues with it working well on my OS (weird), but I dont have problems with it on the 01+ for some reason.
    Sulski Performance Tuning
    2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  12. #12
    Tuning Addict WS6FirebirdTA00's Avatar
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    If it were me giving advice to a first time person, I would tell them the following:

    Cams with negative overlap up to zero, idle 850-900, add 1 g/sec to idle airflow, add 2º of idle timing 1200 rpm and under

    Cams with over 0º overlap up to 15º, idle 900-950, add 2 g/sec to idle airflow, add 4º of idle timing 1200 rpm and under

    Cams over 15º overlap, idle 950-1000, add 3 g/sec to idle airflow, add 6º of idle timing 1200 rpm and under

    Of course this is just to get the car starting, and is not "the right way to do it" just what I have told people in the past that has helped. The fueling reduction is also based on the cam size. I will have to look through some tunes to find out a good run of thumb for that.

    Other than that, the first thing to do is to get your idle fueling close to 14.5-14.7, then using the VCM controls, adjust the timing until you see good MAP (more vacuum). There will come a point at which it doesnt get much better, and that is a pretty good way to get into a sweet spot. If you get some idle surge, chances are you may have too much timing in there. Each setup will want different things (depending on the combustion chamber design). When making these changes, you need to give it some time and let the STIT and LTIT level out somewhat so you can see if it is really helping. I am sure there is more to add, and things some people may not agree with. MOST of the time, if you add idle airflow to the whole table, you dont even need to mess with start up airflow settings, but that doesnt mean you may not have to. If the car has a hard time starting, you can add 0.5-1.0 g/sec to the start up airflow settings to aid in start up.
    Sulski Performance Tuning
    2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  13. #13
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    Thanks for posting up all this info, it is a big help for us beginners. At least we have somewhere to start making changes.
    2004 Phantom Black A4 GTO - Flowmaster catback, Dynatech LT's,Cat delete, Vinci 099 Cam 232*/240* .551"/.551" 117 LSA,Performabuilt Level 2 4L60E, Performabuilt 3K Stall, B&M Tranny Cooler, SLP Line Lock, Nitto DR's, '05 GTO Front Brakes
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  14. #14
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    Thats what we're here for

    So Russ, Soundengineer, RHS...I know you guys all have thoughts on idle tuning...wanna throw in your .02?
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

  15. #15
    Senior Tuner S2H's Avatar
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    well..heres my basic rundown...


    firts thing I do is get the car warm...dont give a dam about idle...just get it up to temperature...
    I also command 28* constant using VCM controls for the moment just to keep spark steady
    check your IAC position... it needs to be in the 60-80ish range at hot idle..fans off..AC off..and I do it with the hood up as well to keep down the heat soak from the IAT...preferrably in the shade on really hot days...

    if its not in the 60~80ish range...on ETC vehicles it equates to about 4% TPS
    I drill the TB blade until it gets there....

    once I get a basic proper air for Idle it usually idles on its own just fine....
    then I go to spark and push it around with VCM controls untiol it sounds correct..for me this comes from years of wrenching on Drag cars...
    a lot of cams are happy anywhere between 24* and 34* so you have to just ply with it to find happiness..
    I do this at all rpms that I feel the car will idle at..meaning if mu cold idle is 1200 then I start there and work back down to as low as I can get it to idle hot...some cams dont like Idle at all...some love it low as you can go..
    good example is a buddy with a 259/263(yes...HUGE)..Idles perfect at 800...lopes like a son of a bitch...all thats done is a hole in the TB and a little bit of Idle spark..

    I also make sure my Idle Spark transitions into my High/Low octane tables so that I dont have any wierd jumps between Idle and Drive.

    I try to rough in my RAF values at the same time as it will effect the idle some as well and I really cant get the idle right until RAF is close...then I ccan fine tune it later...RAF is very slow learning

    IF I am really having Idle issues I start to mess with the Adaptive Idle tables
    usually taking it out of the picture some.....and even sometime just disableing it completely by changing the update error time to its max value...

    worst case...last thing I mess with is the IAC steps vs Effective area table
    I try to lower the values slightly so that its slows the movement of the IAC some...not too mch as IAC can be really needed soetimes...but a little bit doesnt hurt sometimes..unfortunately this isnt the real solution but there no way to change the IAC motor to respond in smaller values...its not like I can change the gear size on it or something cool like that..

    I usually raise my throttle cracker MPH to a higher disable value so it doesnt interfere so uch a well...
    its a PITA table to really tune and theres not an efficient way to do it...

    oh yeah..almost forgot...
    one of the biggest keys to a good idle..is proper AFR at idle...
    14.7 or slightly leaner(15.2 is kind of my max limit) seems to yield a better idle..sometimes I even just push teh fueling around with the VCM controls to hold an AFR I want and fix VE and MAF tables later when I am done with the idle.

    If you run closed loop then you can mess with the closed loop proportional idle tables...but I'm an open loop kind of guy and the majority of my customers enjoy their open loop tunes much better than their closed loop problems....A lot of them go SD as it seems to fare better for most of them as well and they like the throttle response it yields

    hows that for my $0.02
    Last edited by S2H; 03-21-2007 at 09:09 AM.
    -Scott -

  16. #16
    Супер Модератор EC_Tune's Avatar
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    Only thing I will add for idle tuning is to turn OFF the LTIT. No point in having "learning" moving things around while you are tuning.
    These are the values you need to adjust:
    Attachment 4688 Attachment 4690
    Attachment 4689 Attachment 4691
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  17. #17
    Супер Модератор EC_Tune's Avatar
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    And for startup leanness when the engine is hot:

    Attachment 4694 Attachment 4695 Attachment 4696 Attachment 4697 Attachment 4698
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    Супер Модератор EC_Tune's Avatar
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    For LS2/LS7 with cams:
    Add 2-3 G/sec to the Startup Airflow
    And for the Base Running Airflow table - Make it match the MAF/Dynamic Airflow at normal operating temperature at the running idle speed.
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  19. #19
    Tuning Addict WS6FirebirdTA00's Avatar
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    Damn Doug, do you ever go to bed? lol
    Sulski Performance Tuning
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    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  20. #20
    Супер Модератор EC_Tune's Avatar
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    I'm still up.

    Dang. I have a vette to dyno in a couple hours. Forunately it just has simple boltons.
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