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Thread: Long term fuel trim stuck?

  1. #1
    Tuner in Training
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    Aug 2014
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    Long term fuel trim stuck?

    2005 LSJ ss/sc

    so I logged for about an hour today and I am seeing that my LTFT is locked at 9.4% while my STFT fluctuates between about -4 to +5

    something not right?
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  2. #2
    Tuning Addict 5FDP's Avatar
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    May 2012
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    Try resetting the fuel trims in the scanner.

    Do a 10-15 mile log again and see what happens.

    If they go back to +9.4, then you might have a very small vacuum leak or there is a good difference in the maf/ve tune.
    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
    Tuner in Training
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    so I like to try and figure things out before asking a silly question but I am stuck.
    how do you reset the fuel trims in the scanner?
    don't worry, someday I will be helping newbies ;-)

  4. #4
    Tuning Addict 5FDP's Avatar
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    If I remember right, turn the ignition on and then start the scanner and click the VCM controls next to the engine icon. Find the fuel trims reset under there and you should be able to click it, that will reset the trims and now you can start the car. Then just stop scanning and start over.
    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
    Tuner in Training
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    You Sir, are correct.
    Thank you much... It is so simple once you have done it :-/