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Thread: Timing Control: Very erratic timing at idle.

  1. #1

    Default Timing Control: Very erratic timing at idle.

    Hello All. I've got a 4 cylinder turbo with large cam, and I'm seeing substantial timing movement at idle, that goes counter to what the table would be suggesting. I'm using an MSD distributor for the pickup and the table/settings in the below photos. Any ideas why my timing would be so "jumpy"? I'll admit the vacuum signal at idle is anything, but stable with my cam, but I can't reconcile this one.

    Here's the Base Timing Table, as you can see very stable where it says it's overlapping:

    And finally the pickup settings:
    Last edited by Turbo1303; 01-14-2022 at 02:22 PM.

  2. #2


    It appears as though you have Idle Spark control enabled in the IAC settings section in the Idle ICF. The amount of timing change can be adjusted with the P & D Terms. If you want to confirm your idle timing based on the Base Timing Table or if you want to disable this feature simply uncheck the box. The system looks at RPM variations and MAP variations and determines mixture and/or timing changes to maintain a steady idle.

    If you'd like us to look over your setup, download your config from the ECU (use the Save As function to name the Config File uniquely), zip it, and upload it here.

  3. #3
    Join Date
    Dec 2009


    Idle Spark control (in the Idle ICF). It can be temporarily disabled when viewing, verifying or synchronizing the idle timing.

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