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Thread: jerking/bucking on Decel

  1. #1
    Tuner in Training
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    jerking/bucking on Decel

    can anyone look at this log and tell me why when i let off the throttle some times (not all the time) it will buck/jerk? Stock 6.4 on 93 with intake and 3in exhaust (no res/mufflers) and hell cat injectors.

    thanks
    Attached Files Attached Files

  2. #2
    Potential Tuner
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    I have the same issue. Mine is cam swapped and thought that might be the issue. Going to pick up a dongle soon and log it. What rpm does yours do it at and what gear is it in?

  3. #3
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    It doesn?t really have a set rpm or gear as it has happened in all gears but seems more in the lower teens of rpm?s.

  4. #4
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    Mine only seems to do it in 8th gear at around 1100-1200 rpm during coast. Iv also seen/heard it surge at around 3k rpm. Except when it surges at that rpm it’s dropping several hundred rpm and then picking it back up and repeat. I’m pretty certain it has a junk tune on it from a shop that I should have never let touch it. I can’t wait to put an AFR gauge on it and data log it to see what kind of �� he’s messed up.

  5. #5
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    My 2020 Challenger 1320 with 6.4 does the same thing. It has a FRP Tomahawk 2.0 cam now so I thought this is what's causing it since stock form it didn't do it. The 1320's have "default" mode and "drag" mode. It will surge/jerk/buck in drag mode worse. If I ever so slightly mash the accelerator when it starts it will stop jerking. Thinking it might need a higher stall converter.

  6. #6
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    Something I?ve been playing around with is the DFCO on/off settings and I?ve found it to help a ton. This might also be what you guys are feeling or it possibly might be something else. Seeing I?m not cammed i can?t speak on your situations. In HP setting you can raise the temp of engagement to above 300F to disable it and see if that helps or put it back to stock temp setting and adjust the on/off rpm so where it works for you.

  7. #7
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    Quote Originally Posted by Monstar View Post
    Something I?ve been playing around with is the DFCO on/off settings and I?ve found it to help a ton. This might also be what you guys are feeling or it possibly might be something else. Seeing I?m not cammed i can?t speak on your situations. In HP setting you can raise the temp of engagement to above 300F to disable it and see if that helps or put it back to stock temp setting and adjust the on/off rpm so where it works for you.
    You might be on to something. I had to raise the RPM as well along with raising the temp to completely disable DFCO. If I remember correctly I could be wrong. Think I might disable it again and do some driving. See if it still does it with DFCO disabled.

  8. #8
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    i completely disabled mine and it actually made mine worse. as soon as i would let off the throttle it would buck/jerk consistently if i was around 1500rpms. so i enabled DFCO again except this time changed the disabled rpm to 1100 and enable at 1200. this way it would disable before i came to a complete stop and enable before i reached the problem area. in my mind this is only a cover up bandied to my problem and not a fix

  9. #9
    I set them tp 3400 3200.. 12mph 10 mph. Good luck

  10. #10
    Potential Tuner
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    Any updates on the dfco settings you changed?

  11. #11
    Anymore on this? Anymore thoughts on strategy to deal with it?

  12. #12
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    If you still haven't resolved this, do me a solid and post your tune. I wanna take a look at those spark tables and a couple fuel settings.
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  13. #13
    I'm out of town at the moment but keen to discuss. Be back at my laptop in a few days.

  14. #14
    Ok. I found the issue on my settup. I have removed the previous posts as I was on the wrong path. On my settup it turned out to be the converter lock up setting in 4th.