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Thread: Truck goes into limp mode after tuning. Anyone have this happen before?

  1. #1
    Potential Tuner
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    Jan 2020
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    Manchester Tennessee
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    Truck goes into limp mode after tuning. Anyone have this happen before?

    Didn?t do any crazy changer. Stock 09 Silverado 5.3. P068 and p0106

  2. #2
    Advanced Tuner
    Join Date
    Sep 2018
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    Quote Originally Posted by Williams1x80 View Post
    Didn?t do any crazy changer. Stock 09 Silverado 5.3. P068 and p0106
    Normally see this when speed density and MAF are too far apart. You can stop it from happening by maxing out your "MIN ECT", Setting "Max ECT" to -39 and raising the "Enable RPM" under Airflow Correlation. More of a band aid though as you stated the truck is stock.

    I don't know what you adjusted since you don't have the file attached but if you adjusted your MAF incorrectly, SD incorrectly, or only changed one of them drastically that's probably your issue. I wouldn't think you've exceeded your airflow limits vs RPM or ignition volts as you state it's stock so the issue is probably from exceeding the airflow delta or map delta. Log your Mass Airflow and Dynamic Airflow and compare the two. It's probably far apart.

    If you choose not to tune MAF & SD evenly to resolve this for whatever reason just make sure if your adjusting ignition timing and logging knock/retard in the scanner that your histogram is set up correctly. The Y axis will need to have a user defined math based on dynamic airflow vs the using the usual PID for cylinder airmass or spark airmass.

    This information is assuming you have no vacuum leaks, good throttle body, good MAF & MAP, and everything mechanical is in order.

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