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Thread: Idles really low when clutched pushed on decel/ Runs perfect with VSS unplugged

  1. #1
    Potential Tuner
    Join Date
    May 2013
    Posts
    4

    Idles really low when clutched pushed on decel/ Runs perfect with VSS unplugged

    Hi everyone. Total rookie here. I have a 66 Chevelle LS2/T56 with a DBC P01 ECM. It has a Tick Performance Cam (231/235 | .625"/.605" | LSA111+2), 102mm throttle body and sheet metal intake, LS7 Card style maf, Hooker Blackheart headers and Borla Exhaust. This is is my first time tuning anything so don't hold back. I have the car running good as in it starts up good when it's cold or hot, and drives great in all conditions except one. When i push the clutch in when coming to a stop it tries to die (Idle drops to ~600 and sometimes lower or dies) As soon as the VSS reads 0 in the scanner, the idle pops right back up to where it it supposed to be. If I disconnect the VSS it seems to run great all the time but then I don't have a speedo. What would I look at to correct this issue? I have included the tune and a scan of quick drive. Thanks everyone.
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    Last edited by KeaneVann; 09-21-2020 at 12:07 PM.

  2. #2
    Senior Tuner
    Join Date
    Jan 2013
    Location
    Hawaii
    Posts
    2,101
    Add to the rolling idle airflow until the desired rolling idle is achieved, or lower the Airflow TPS Max and use the throttle cracker tables if you get too much of a RPM hanging/ oscillation issue right after clutching in.

  3. #3
    Advanced Tuner
    Join Date
    Sep 2017
    Posts
    736
    Looks like this tune needs some work. But log throttle cracker and throttle follower.
    If my hunch is correct both throttle follower and cracker will decay direct to ZERO with the clutch pushed in. I seen this with the same OS/FBody application on my buddies car.

    What we did is we activated rolling idle. We did the rolling idle rpm with an decending value from 100 mph to your desired idle rpm.

    We used the rolling idle airflow as the follower/cracker by taking the airflow numbers from the PID setting and adjusting accordingly. It worked very well.
    1997 30th SS. Torqhead 24x, TFS heads, 223/235 cam, 4l80e, S60 D1SC 14psi