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Thread: 8.1 vortec manual trans wont rev past 3000 rpm

  1. #1

    8.1 vortec manual trans wont rev past 3000 rpm

    engine was originally an allison and now have a manual. truck runs and drives fine just wont rev past 3000 rpm. log and tune posted

  2. #2
    Tuning Addict 5FDP's Avatar
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    Try increasing your park/neutral rev limter.

    There are two places you must change. The cutoff and resume has a limiter at 3,250 and your in gear tab has a limiter right at 3,250 rpm.

    Then the ETC gear based tab has a limiter at 3,000rpm.
    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
    change those values in both spots. pretty much the same out come except it bounces of the limiter at 3500rpm. also have p1781 engine torque signal circuit pending. ive read in had to due with the ecm and tcm from the allison not communicating. im not sure what to change in the tune to stop the attempted communication

  4. #4
    Tuning Addict 5FDP's Avatar
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    Just turn the code off, you left it on still. Change it to no error reported and uncheck the SES box.

    Other than the 3 spots that had 3000-3250rpm limiters, I'm not sure where else there is a limiter.
    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