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Thread: AFR very rich after startup airflow, SD tune, scaled for injectors

  1. #1
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    AFR very rich after startup airflow, SD tune, scaled for injectors

    Havent messed with this thing for a while and trying to get it back up and running and fixing the problems its always had.

    2012 gmc yukon e38/t42, 427cuin, 4l80, log style turbo manifold, 92mm, 1300cc injectors,

    my biggest problem right now is the startup,

    Ive got the startup airflow pretty well set to get everything moving (first couple seconds), but towards the end the commanded AFR goes very deep, .546 lamba (afr shows 14-16 but my stoich is set to 29.4) it will then bobble around for 20-30 second till it enters idle (?) state i'm guessing. its possible i didnt double/half a table i was supposed to but i cant find/search of any table that would effect that little bit of time, im pretty sure its an OL table but none are obviously way off to me.

    thanks!
    23-04-15 09-34-50.hplyukon 4-14-23 2.hpt

  2. #2
    Tuning Addict blindsquirrel's Avatar
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    What injectors are they, can you post or link to the datasheet?

    edit: Is MAF removed, or still connected but failed? Those are some strange Fail High/Low numbers right there....
    Last edited by blindsquirrel; 04-15-2023 at 12:31 PM.

  3. #3
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    fuel injector clinic 1200cc* rather
    https://fuelinjectorclinic.com/HP-TU...QaAoBJEALw_wcB

    maf completely removed, gm temp sensor put in the intake manifold (after intercooler)

    fail high/low? o2 sensors? - just realized you meant the maf hi low... i probably was trying to tune the VE at the time i decided to abandon it all together and never changed anything
    ive order some new ones, wont be here till monday
    Last edited by randeez; 04-15-2023 at 12:37 PM.

  4. #4
    Tuning Addict blindsquirrel's Avatar
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    I think I would use 0/0 or 2/1 for the fail high/low.

    Injector data & scaling looks ok - I get very minor differences if I copy from the sheet and paste, but they're mostly in cells located outside any realistic operating window.

  5. #5
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    thank you for takin a look and confirming the scaling
    changed the MAF hi/lo fail to 2/1
    looking back at old old tunes i noticed that COT had max enrich at 1.25 and was zero'd out somewhere along the way so i put a value back in there, it is disabled but who knows
    will go try a startup in a bit

    any other ideas? open to suggestions

    tried a startup, not much changed.

    there is some discrepancy between nbs and wb... i had been following the nbs for the low rpm, but the wb error correction seems to be going the other way 6-8% more fuel and it seems to idle better with it. during startups wb is showing 10%+ error in the cells it hits (nbs arent active yet). going to make corrections per the wb and see if it helps clear up some
    Last edited by randeez; 04-15-2023 at 10:13 PM.