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Thread: Surging when stopping

  1. #1
    Tuner in Training
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    Surging when stopping

    When coming a stop the motor will surge up/down a few hundred RPMs I'd say 70 or 80% of the time. Other times it stops without issues. I also see some slight surging when downshifting around 30 to 20 mph under no throttle but majority of the issue is when coming to a stop. Motor starts and idles fine. Runs very strong....just idle issues when coming to a stop.

    I've tried varies settings for idle torque spark and throttle in IDLE > AIRFLOW. Tried varies settings starting with stock Trackhawk and Demon files, and then modifying from there with no luck. Putting truck in tow/haul mode will prevent this from happening as it keeps downshifts up high in the RPM range, but can't drive around in TH all the time. Truck is a daily driver. At one point I thought I had it licked but still surged very slightly so kept at it to get it to 0, but now its slightly worse and can't get back to settings where it wasn't that bad. Ugh.

    If anyone can point me in a direction it would be most appreciated. Attached tune and sample log of issue (look at last 30 seconds of log).

    Aside...want to thank this forum for the wealth of knowledge. Spent countless hours reading and learning. Also purchased the Tuning School program for both dodge engines and transmissions. Nice program and a great starter for anyone wanting to start tuning.
    Attached Files Attached Files
    Last edited by VooDooButter; 11-19-2020 at 07:18 PM.
    2019 Ram 1500, 6.4 BGE Block, 426/7.0 Manley Forged Kit, Harrop/Eaton 2650 SC, CAI, ThiTek CNC Heads, Studs, Comp Cam 230/244 .608/.597 118+6, MDS Delete, ID1050 Injectors, 100mm BBK TB, ARH Long Tube, Corsa Exhaust

  2. #2
    Tuner in Training
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    I fixed the issue. I saved a few dedicated scans of when this would happen and found a common theme.....something was pulling torque when coming to a stop, but not all the time. Slowly coming to a stop was fine, but normal or fast stops would cause the motor to swing widely. Reviewed all torque tables and found the Power % Request tables in torque management were jacked up. A number of people have been involved with this tune and my theory is someone left this table a mess when they were trying to address a torque limit issue, and modified the NVRatio row values along with leaving too high a percent between cells around idle. This caused the motor to pull torque jumping between 2 huge values causing the swing in RPM.
    2019 Ram 1500, 6.4 BGE Block, 426/7.0 Manley Forged Kit, Harrop/Eaton 2650 SC, CAI, ThiTek CNC Heads, Studs, Comp Cam 230/244 .608/.597 118+6, MDS Delete, ID1050 Injectors, 100mm BBK TB, ARH Long Tube, Corsa Exhaust

  3. #3
    Thank you for updating with the solution , so to make it clear to changed the values to a more linear value and smoothed it ?

  4. #4
    Tuner in Training
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    NJ
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    Basically. Keep the values closer together or equal around idle/nvratio and keep it smooth. Graphs help visualize the numbers. This worked for my scenario so ....

    I spent a lot of time adjusting the idle torque spark tables first under idle > airflow. This got me very close but still had the random annoying surge when coming to a fast stop. That is when these other tables helped. VE tables / timing should be rock solid before doing these other adjustments.
    2019 Ram 1500, 6.4 BGE Block, 426/7.0 Manley Forged Kit, Harrop/Eaton 2650 SC, CAI, ThiTek CNC Heads, Studs, Comp Cam 230/244 .608/.597 118+6, MDS Delete, ID1050 Injectors, 100mm BBK TB, ARH Long Tube, Corsa Exhaust