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Thread: Can someone explain why my bank 2 LTFT is dumping 25% fuel?

  1. #1
    Tuner in Training
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    Can someone explain why my bank 2 LTFT is dumping 25% fuel?

    Doing a log on the highway tonight and my engine light flashes. I read the code and it comes up as lean bank 2. Look down and my bank 2 LTFT is pegged at 25% and the car starts running like dogshit. Probably washed down my cylinders and fouled my plugs.
    Have no clue where to start. gto na 6.hpl

  2. #2
    Tuning Addict 5FDP's Avatar
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    You have your positive and negative mixed up.

    That is showing +25%, so that means it's lean and not washing the cylinders down because it's rich.

    The log is missing your o2 sensor data so you can't tell if that o2 sensor failed. Other causes are a vacuum leak or an exhaust leak on that side. Possible that fuel pressure is low as well.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
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    So its pulling 25% fuel? Or adding 25%? Also what should I have in the channels, 02 sensor voltage? It pulls like normal at WOT so my fuel pressure is there.

  4. #4
    Tuning Addict 5FDP's Avatar
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    Positive means it's adding fuel because it's lean. So it's adding in 25% on the long term to try and bring fueling back to normal.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  5. #5
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    Ok so check vac leaks, exhaust, and check 02 voltage in the scanner? There is no way that bank is 25% lean, my motor would have been smoked by now.

  6. #6
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    The +% LTFT and STFT brings the bank back to stoich unless the max% they can add is reached and it is still not enough.

  7. #7
    Senior Tuner TheMechanic's Avatar
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