Results 1 to 5 of 5

Thread: knock retard after adding e85

  1. #1

    knock retard after adding e85

    I added the e85 sensor to my 2018 silverado. I am running 70% right now. In a log today I noticed 3-5 degrees knock retard. Being at 70%, I know this cant be real knock, esp when the tune is set to 10-15 degree in those areas. The main spark advance channels all show 0, knock learn is 0, no burst knock.

    19-09-05 16-14-33.hpl

    Can anyone glance at my log and see if anything sticks out? I can log more PIDS if need be.

    Thanks!

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,559
    It's not really a problem when it happens under very low load and at around 1,600-1,800rpm.

    I've seen this happen when it's lugging in gear and the torque converter locks or when it's coming on and off AFM/DoD.

    I always disable the TCC in gear 1-4 because I dislike how the transmission behaves when it active like factory. Would be worth a shot to disable your TCC and see if that helps any.
    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
    interesting.. what param controls TCC? I dont have my 87a unlocked, so prolly cant do that yet anyhow.

  4. #4
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,559
    I don't know off hand if there are TCC tables in the 8 speed auto file or how many there are if there are. I've just done several 6 speed trucks to know what I can set/change to make the TCC stop engaging in the lower gears. GM pretty much made it so that the torque converter would lock in every gear no matter what.
    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
    In the T87 go to TCC /apply/release. 8l90 has both part throttle and WOT lock up tables. Never cared for how GM locks the converter in all gears so I changed mine to not lock until 8th gear 55mph.