Results 1 to 2 of 2

Thread: 4L80E problem over 6000RPM 1-2nd shift Please Help!!

  1. #1
    Potential Tuner
    Join Date
    Jul 2014
    Posts
    5

    4L80E problem over 6000RPM 1-2nd shift Please Help!!

    Hi I have a 1989 Caprice with a 2008 6.0L LY6 with a LS3 cam / 4L80E with transgo hd-2 shift kit the car was tune on a dyno but I?m having problem with the transmission, when I make it shift from 1st to 2nd gear over 6000rpm it seems like it goes in limp mode. In scanner mode you can see that the accelerator pedal is at 100% to whole time but the throttle position start to drop and you can fell the limp mode and then shift in 2nd gears , but from 2nd to 3rd I can shift it over 6000rpm without problem . Also I?m having problem with the throttle response it seems to be slow under 4500rpm

    thanks
    Attached Files Attached Files
    Last edited by 1984toyota; 09-14-2019 at 07:57 PM.

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,559
    How sure are you that the dyno person knew what they were doing?

    I see 9.75 commanded AFR at full throttle on a NA engine, I kinda stopped there because I'm not even sure the airflow model is correct and that is more than half the battle with getting the transmission to do what you want.

    Your logs have channels that aren't really totally related to GM cars, lots of possible missing data and lots of stuff you don't need.

    Limp mode or REP would toss a code, so that is not the problem you are having. This is going to be a engine calibration issue and transmission calibration issue that needs lots of time to dial in.
    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.