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Thread: Inconsistent AFR in PE

  1. #1
    Potential Tuner
    Join Date
    Sep 2017
    Posts
    6

    Inconsistent AFR in PE

    Hey guys,

    I've been experiencing what I believe is a bit of a strange issue. My PE commands 12.6 and Im observing AFR though a wideband gauge.

    When driving in top gear on the highway at say 1900 to 2600 RPM I enter PE I will get incosistance ratios. About 75% of the time I will get right around 12.6 but sometimes it will be as lean as 13.0 or rich as 12.1

    This will happened on back to back pulls on the highway.

    This may clear up higher in the rpm range but I've not observed it enough.

    I've tuned MAF and VE tables to a percent or two using STFT and LTFT are disabled. Its currently setup to use MAF and VE like stock.

    Is this some strange blending issue? I don't understand why it will vary so greatly. Would I be better off running straight MAF or VE?


    Thanks guys,

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,533
    Are you able to see if fuel pressure is staying constant when this issues happen?

    What kind of vehicle and computer is this running?

    Do you have anything like COT active or removed rear o2 sensors if it's a P59 controller that can't diabled the cat tests?
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.