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Thread: STFT and LTFT majorly different from bank to bank ideas

  1. #1

    STFT and LTFT majorly different from bank to bank ideas

    We are seeing huge differences from Bank 1 to Bank 2 on a LS6. Car runs like crap and seems to be an electrical issue. Any ideas what could be going on here? O2 sensors are new but sure don't look right.

  2. #2
    I can't see the scan because my internet is being a punk....

    But, a complete stab in the dark?

    Is this a motor swap? Is it the correct computer/OS for that engine?

    I only ask because I just went through extremely split BLMs due to a motor swap and the PCM wasn't true to the engine.

    Custom PCM Tuning in Hollywood Ca

  3. #3
    Not really now that I looked at the last log again they are both commanding a ton of fuel but we have gone both ways with the VE table with no better results. I've also scaled the injector table as a quick way to trim down fuel with no better results. It had a dead O2 sensor and so we replaced it, then the other was not responding and so we replaced it also.

  4. #4
    Tuning Addict WS6FirebirdTA00's Avatar
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    Jan 2005
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    Put it in OL, put a WB in each bank, and verify if it is an o2 issue or not.

    What mods do you have? You really need to delete the worthless PIDs for a faster sample rate.
    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

  5. #5
    which PID's are you talking about?

  6. #6
    Tuning Addict WS6FirebirdTA00's Avatar
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    IAC position
    Desired IAC position
    TPS volts
    FTC
    Calculated cylinder air
    Trans current gear
    Commanded AFR (not doing much for you without a WB)
    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

  7. #7
    Tuner in Training
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    i live in ny, but i'm in memphis right now
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    I have a similar problem, but only about 1 on the stft, from 1 bank to another. stock lq4 motor. i read somewhere that you can use propane to find air leaks around injectors/ intake. watch your afr, and look for a jump when it sucks in the propane instead of ambient air. i have yet to try this on my truck, but hope to soon.

  8. #8
    Advanced Tuner
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    Jul 2014
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    Ever find the problem ?
    I'm having a similar issue after doing a new cam . But I also did a trans removal and hope I didn't mess up a sensor during removal-

    I'm getting a large differance, as much as +25 on bank 1 and -26 on bank 2 at times .

  9. #9
    Advanced Tuner
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    Have you checked the wiring? The O2's are back there near the trans, perhaps you have the bank 1 and bank 2 O2 wires swapped?

    Jason
    1996 Camaro SS M6 - 24X conversion - stock bottom end - heads - shorty headers - 58mm TB
    Ultradyne 230/238 .565/.565 112+4 - 30 LB red top SVO injectors - LOTS of suspension...

    2002 GMC 2500 HD Duramax M6 - Just starting the tune on a stock motor now that I have a good clutch on order...

  10. #10
    Advanced Tuner 68Camaro's Avatar
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    Have you checked the wiring? The O2's are back there near the trans, perhaps you have the bank 1 and bank 2 O2 wires swapped?
    This^

    I just tuned a truck (65 chevy with a LY6 swap) and had this exact problem last week.