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Thread: random stall at idle

  1. #1
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    Default random stall at idle

    Ive been fighting this off and on for some time and im looking for some help on this..

    seems to happen noticeable once warm and will be slowing down to stop, push in the clutch rpm drops (i think just a little too quick) and over shoots the idle speed and will stumble a bit and stall or sometimes catch and come back up to the desired idle

    ive tried adjusting the TC and TF with decay no help.

    i have cleaned the IAC thinking it may be carbon causing it to randomly stick or be too slow with no change



    the cam is not very big so I would think its something I'm just overlooking.

    info below
    Since this is a tuning site.... LS1 swap, 224/228 .588/.588 114+1 , LS6 intake , Ported TB, LS6 Valley cover (huge difference in oil usage!) 36# grand prix injectors, SLP Thirdgen dual air box cold air, Stage 2.5 Ported PRC ls6 heads, Hawks ls1 1 5/8 swap long tubes, SLP Thirdgen Catback t56, spec 3 clutch, S60 street 3.73 rear. LC-1 WB , Roadrunner

  2. #2
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    Default

    Post your tune and a log.

  3. #3
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    Default

    i dont have a problem doing that but what PIDs do you more experienced suggest I use for the log to obtain the best view on whats going on?

    RPM
    TPS
    Ignition Timing advance #1 cyl
    IAT
    ECT
    Commanded A/F ratio
    MAP
    MAF grams second
    guessing one of the O2 sensor mv (bank 1)
    IAC position
    Desired IAC position
    Since this is a tuning site.... LS1 swap, 224/228 .588/.588 114+1 , LS6 intake , Ported TB, LS6 Valley cover (huge difference in oil usage!) 36# grand prix injectors, SLP Thirdgen dual air box cold air, Stage 2.5 Ported PRC ls6 heads, Hawks ls1 1 5/8 swap long tubes, SLP Thirdgen Catback t56, spec 3 clutch, S60 street 3.73 rear. LC-1 WB , Roadrunner

  4. #4
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    Default

    Sae.tp
    sae.rpm
    sae.vss
    sae.maf
    sae.map
    sae.iat
    sae.ect
    sae.sparkadv
    gm.afr
    gm.ibpw1
    gm.iac
    gm.iacdes_b
    gm.iac_sum_dma

  5. #5
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    Default

    idle_0000.tunLog_idle.efi

    here is the current tune and log with it acting up
    Since this is a tuning site.... LS1 swap, 224/228 .588/.588 114+1 , LS6 intake , Ported TB, LS6 Valley cover (huge difference in oil usage!) 36# grand prix injectors, SLP Thirdgen dual air box cold air, Stage 2.5 Ported PRC ls6 heads, Hawks ls1 1 5/8 swap long tubes, SLP Thirdgen Catback t56, spec 3 clutch, S60 street 3.73 rear. LC-1 WB , Roadrunner

  6. #6
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    Default

    Your spark and fuel look alright. Your desired airflow looks a bit low. Use your roadrunner to slowly bump up your Desired Airflow {B4307} while you drive around... see if commanding more idle airflow helps at all.

  7. #7
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    Default

    I will give that another shot.. I tried a little before but maybe it wasnt enough

    LABELS Desired Airflow (Grams/Second)
    ECT °C {link: SAE.ECT} In Gear Park/Neutral
    -40 24.500000 0.000000
    -28 22.786133 0.000000
    -16 21.186523 0.000000
    -4 19.741211 0.000000
    8 18.295898 0.000000
    20 16.455078 0.000000
    32 15.008789 0.000000
    44 13.563477 0.000000
    56 12.248047 0.000000
    68 11.099609 0.000000
    80 10.484375 0.000000
    92 10.000000 0.000000
    104 9.619141 0.000000
    116 9.356445 0.000000
    128 9.093750 0.000000
    140 8.936523 0.000000
    Since this is a tuning site.... LS1 swap, 224/228 .588/.588 114+1 , LS6 intake , Ported TB, LS6 Valley cover (huge difference in oil usage!) 36# grand prix injectors, SLP Thirdgen dual air box cold air, Stage 2.5 Ported PRC ls6 heads, Hawks ls1 1 5/8 swap long tubes, SLP Thirdgen Catback t56, spec 3 clutch, S60 street 3.73 rear. LC-1 WB , Roadrunner

  8. #8
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    Jul 2008
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    Default

    I raised the desired airflow from the bottom up about part-way (from what I think this is the area the stall happens the most ) instantly could tell a difference just by bliping the throttle and watching the rpm come down to idle. I waited until it finally stopped raining long enough and i took the car out to test. it seems much better and didn't stall once. seemed like it had better control over the engine speed as it brought the rpm down to idle.

    things I noticed were cold and coming to a stop idle seemed to hang just a tad too long at first but I think I can get that sorted out or even leave it as is since i barely noticed it.

    the other thing i noticed was after the drive I was on the last stretch heading home and the car had a surging with light throttle while keeping a steady speed. I did a search and looks like possible might have too much air commanded at the load? or spark perhaps is not steady or smooth transition? I will have to run a log again and see what its doing.
    Since this is a tuning site.... LS1 swap, 224/228 .588/.588 114+1 , LS6 intake , Ported TB, LS6 Valley cover (huge difference in oil usage!) 36# grand prix injectors, SLP Thirdgen dual air box cold air, Stage 2.5 Ported PRC ls6 heads, Hawks ls1 1 5/8 swap long tubes, SLP Thirdgen Catback t56, spec 3 clutch, S60 street 3.73 rear. LC-1 WB , Roadrunner

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