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Thread: P.I.D. Question

  1. #1
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    Default P.I.D. Question

    which PID is used by the pcm for the spark maps? dyncylair or cylair? this is for a 2003 silverado 4.3L
    ls1b controller.

  2. #2
    EFILive Reseller wait4me's Avatar
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    An easy way to tell is, simply go to the calibration table you want to see. In your case maybe B5913 which is the high octane spark table.
    Then look at the AXIS names for column ect.. In this case it tells you exactly what your question was.
    DYNCYLAIR_DMA at the top, and SAE.RPM on the side.
    "If you can leave a black mark on the pavement, from the exit of one corner to the braking point of the next one, you have enough horsepower."

  3. #3
    Joe (Moderator) joecar's Avatar
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    +1 what wait4me said.

    Also, for some calibrations, the spark table axis mentions more than one airmass (g) pid... you can log which ever of these pids that your PCM supports.

  4. #4
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    so which pid do i use for the scan log? the pid list shows dyncylair but not dyncylair_dma

  5. #5
    Joe (Moderator) joecar's Avatar
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    Try GM.DYNCYLAIR and see if it logs (i.e. produces reasonable values).

  6. #6
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    it doesnt have gm.dyncylair. it has dyncylair, cylair, cylair_m
    Last edited by calif0rnia; November 27th, 2020 at 08:45 AM.

  7. #7
    EFILive Developer Site Admin Blacky's Avatar
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    It's been a long time since I looked at the LS1, so hopefully I am remembering this correctly (feel free to correct me if I'm wrong).

    For LS1, I would use CYLAIR_M or DYNCYLAIR_M depending on the requirements below. The "_M" (or "_DMA") suffix indicates PIDs that are not normally available from the ECM. EFILive has analyzed which memory locations are used to lookup the data in various table and the _M PIDs report the exact value used by the controller for table look-ups.

    Requirements:
    1. CYLAIR_M is available when a MAF is fitted and fully functional - it is computed based on the MAF values.
    2. DYNCYLAIR_M is available when the MAF has reported a fault code - i.e. when a MAF is not fitted (or faulty) - it is computed using the MAP, RPM and IAT values.


    Note: DYNCYLAIR (without the _M suffix) is a predicted value that the PCM computes from a number of sensor inputs (MAP, RPM, IAT etc). I can't remember (don't know) why it needs to predict the g/cyl ahead of time, I think it is 2 ignitions cycles ahead. It then uses (averages?) the around 5 predicted and past values to arrive at the value used for the lookup (i.e. DYNCYLAIR_M). So you may see very small discrepancies between DYNCYLAIR and DYNCYLAIR_M - I don't think the discrepancies would be significant, except maybe during a high rate of change of airflow, like transitioning from 0% throttle to 100% throttle instantly (or vice-versa).

    Regards
    Paul
    Before asking for help, please read this.

  8. #8
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by calif0rnia View Post
    it doesnt have gm.dyncylair. it has dyncylair, cylair, cylair_m
    In the V7.5, GM.DYNCYLAIR is the dyncylair you refer to... are you able to log this...?

    If GM.DYNCYLAIR does not appear on the axis of the spark tables, there is a file that can be edited to add this pid name to the spark table axes (B5913, B5914).

  9. #9
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    i dont know, ill have to look. i use v8 for scanning and v7.5 for tuning

  10. #10
    Joe (Moderator) joecar's Avatar
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    Are you able to log DYNCYLAIR using V8...?

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