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Thread: High, Low Timing Tables on E38 ECM MAF Fail

  1. #1

    High, Low Timing Tables on E38 ECM MAF Fail

    I have searched for hours and cannot find a for sure answer. On the Gen 3 ECM's when running in SD (MAF fail) you copy high octane table to low. But what about the Gen 4 E38 ECM? Some say that in MAF fail the high octane table still works, or do I still copy high to low? Still running the stock OS, no 2 bar patch or anything (not available for my OS). This is for a supercharged LS2 and the plan is to run it in SD mode. Thanks

  2. #2
    Advanced Tuner
    Join Date
    Apr 2011
    Location
    Chicago, IL
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    763
    unless your running a 2 bar os when you fail the maf and go speed density only it will default to the low octane spark chart so yes you will need to copy your high octane to your low octane to get proper spark

  3. #3
    Thanks!

  4. #4
    Also, if you run in SD on low octane table does ecm still pull timing if knock is detected?

  5. #5
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
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    13,533
    Yes it will, but it no longer can use the knock learn factor so it's better to set the timing safer because it can't pull the timing and make it stay out. It will yank timing when it knocks but then puts it right back in once it says it's gone, instead of slowly adding it back in as the knock learn factor returns to normal. This is how I understand it.
    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.

  6. #6
    Thank you for your help.