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Thread: Erratic AFR/Surging & Stalling

  1. #1

    Default Erratic AFR/Surging & Stalling

    I've noticed that the AFR seems pretty erratic and the system has a very difficult time keeping it close to my setpoint at idle (14.1). I took a datalog of a cold start this morning. Once the engine warmed up, I held the throttle steady at 3% and noticed that the engine started to almost cut out, and surged up and down rhythmically. After releasing my foot and the TPS going back to 0%, the AFR surged to 30+ and the engine stalled out completely. Does this sound like my WBO2 sensor has gone bad? The crazy surging wasn't happening the other day, but looking back at past datalogs, I can see that the AFR fluctuates quite a bit.

    Global Config File:

    Data Log #1 (cold start to stall out): Never mind, looks like this datalog flaked out and ended up being only 16 KB, and the datalogger won't open it - even though the datalogging was active for about 8 minutes. Fun. Here's a link to it anyways:

    Data Log #2 (showing more of the surging):

  2. #2


    I just took a datalog with Closed Loop Compensation disabled and there is no surging:
    Last edited by skizot722; 12-24-2019 at 02:35 PM.

  3. #3


    Anyone have ideas about the issue visible in the datalog? Any help would be greatly appreciated, as I'm kind of at a loss on where to look on this one.

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