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Thread: turbo Silverado lean spikes/stumble

  1. #11
    Lifetime Member BLK02WS6's Avatar
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    This thing has me stumped. Still hitting the same wall at around 3k RPM. Running VE only right now and have it close enough that it shouldn't be doing this. Tune and log attached...
    Attached Files Attached Files
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  2. #12
    Joe (Moderator) joecar's Avatar
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    If you're correcting VE (VVE) did you first do this:
    - disable MAF (make a MAF DTC trigger immediately)...?
    - disable CL, LTFT, STFT...?

  3. #13
    Joe (Moderator) joecar's Avatar
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    Which VVE table are you editing...?

  4. #14
    Lifetime Member BLK02WS6's Avatar
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    Quote Originally Posted by joecar View Post
    If you're correcting VE (VVE) did you first do this:
    - disable MAF (make a MAF DTC trigger immediately)...?
    - disable CL, LTFT, STFT...?
    the MAF is unplugged (signal wire)
    LTFT are disabled - I am only correcting the boost area trying to get through this trouble spot to make sure it is not mechanical before tuning the whole thing. Just didn't want the LTFTs staying in during PE and effecting fueling
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  5. #15
    Lifetime Member BLK02WS6's Avatar
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    Quote Originally Posted by joecar View Post
    Which VVE table are you editing...?
    B8105 IMTV open 3Bar table
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  6. #16
    Lifetime Member BLK02WS6's Avatar
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    This thing is really frustrating me! During a pull, it bucks, and IBPW, airflow, and MAF frequency all get spikes. Also the wideband shows large spikes as well. This is in OL with the MAF online. I am going to unhook the signal wire and see what it does with the MAF offine.

    I have found other posts with people having similar issues, and none of their remedies have helped this one. I will attach a log and the tune that it came from. Any ideas?
    Attached Files Attached Files
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  7. #17
    Joe (Moderator) joecar's Avatar
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    ( BTW: 28 pid channels is making the sample rate slow down... try reducing to 24 pid channels, and in Edit->Properties->Logging select Stream Fast. )

    ( BTW: Log ETCTP instead of TP )

    It looks like the ECM is closing the throttle due to exceeding one of the Electronic Throttle sanity tables (in Engine Diagnostics)... it's a matter of figuring out which one and increasing the upper threshold.... but, I see those are already maxed out... it seems the 512 g/s threshold (which is max) might be being exceeded.

    Yes, try without MAF.

  8. #18
    Lifetime Member BLK02WS6's Avatar
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    Thanks Joe! I thought I got all of the ETC tables, but I'll check again. So, if we are exceeding 512 g/s, that means we have to scale the tune, right?

    Tuan - change the logs like he says above - I didn't notice you added some more. Always keep it to 24 channels. Change to ETCTP.
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  9. #19
    Joe (Moderator) joecar's Avatar
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    ( look at bottom of PIDs tab and/or Data tab to see Pids Channel count... some pids take 2 or more channels )

  10. #20
    Joe (Moderator) joecar's Avatar
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    Yes, you may have to scale VE/MAF/IFR (if you're using MAF).

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