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Thread: LTFTs while in SD Tune?

  1. #1
    Tuner in Training
    Join Date
    Apr 2006
    Posts
    42

    LTFTs while in SD Tune?

    I am setting up a 2005 CTS-V with an LS6 and some bolt ons.

    Failed MAF, logging AFR error on my wideband and I left the STFT and LTFT PIDS in my table display.
    I also left the Fuel System Status PID in my table display to make sure it was going into Open Loop.
    STFT's do nothing while logging(stay at 0) but the LTFT's are still there and log on the VE -LTFT histogram.
    Is this normal? Should I just delete them from my table display?

    The LTFT's were displaying about 20 to 25% and likewise my AFR Error via the Wideband was shoing 20 to 25% error from my commanded AFR which was set to Stoich.
    My wideband was showing way rich at idle(10.5) and anywhere from 11-13 AFR while on my short test drive.

    Is there a way to make sure the ECM is going into Open Loop or is using the Fuel System Status PID correct?

    I will post my log and tune if needed from my other computer.

    Thanks in advance!

  2. #2
    Tuner in Training
    Join Date
    Apr 2006
    Posts
    42
    I played around with it more and answered my own question. I was in open look but the ECM had the stored LTFT's of 25% still in there, really kinda screwing my fueling up.

    I reset fuel trims and it seems to be much much better. About 10% at idle anywhere from 5-10% at part throttle

    Wideband shows around 12.5-13 at idle and 14ish at part throttle.

    Now the LTFT histogram logs 0's all over just like the STFT histogram.

    Hope this helps someone else out!