Results 1 to 4 of 4

Thread: Strange Backfire on Throttle Transition

  1. #1
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    29

    Strange Backfire on Throttle Transition

    I'm 99% sure its something stupid because I have changed 100 things and nothing has affected the problem. Setup is an E38/T56/LY6 with a 231/243 cam. Its runs great other than any fast throttle transition increases. 6th gear obviously being the worst as it can not accelerate fast enough to "push" through it. On/Off throttle really makes it pop and bang but it basically does it once or twice and then its done. I changed the entire transition throttle stuff on this log and as usual nothing changed. We tried a new throttle body just in case that was it, pulled/added 25% fuel, pulled/added 15* timing, and I am tuning this via MAF only.
    Attached Files Attached Files

  2. #2
    Advanced Tuner
    Join Date
    Oct 2013
    Posts
    211
    Its going lean on tip in, need to spend some dialing in your VVE/maf tables. you could also have PE come in sooner which may help alleviate your issue but its not the correct way to fix the problem.
    lean tip in.png

  3. #3
    Advanced Tuner
    Join Date
    Feb 2015
    Location
    Perth, Australia
    Posts
    974
    try setting the dynamic enable rpm to suit being MAF only

    also up the PE enrichment rate

  4. #4
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    29
    I thought it was going lean on tip in too, but adding 25% more fuel didnt change anything, so I took away 25%, still nothing. I'm guessing I need to mess with the VVE tables as its probably a transitional thing. And yeah I dont like using PE to fix stuff like this. Is there a VVE calc that works with the new software? I havent used the calc in a while as typically these MAF cars just work

    I'll try the dynamic enable, hadnt thought of that. It doesnt really do it on the PE transition, just the initial hit (that hit can be as little as 40% throttle from no throttle input, but very slow small increases it wont do it) at any rpm. I have upped the PE rate twice to see if it changed anything. Wouldnt hurt to do it again I guess. I was leaning towards air flow throttle stuff this morning

    In 6th gear, under 1600 rpm, you can give it about 30% throttle and it does whatever its doing like crazy. It doesnt pop and bang but the MAF is jumping around about 10 cells and you can tell its not happy.
    Last edited by Jenson; 06-26-2019 at 06:22 AM.