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Thread: Problem with with spark being added and causing knock

  1. #1

    Problem with with spark being added and causing knock

    Hello All,

    I am struggling figuring out what is adding spark. If I have spark set at 32* I will get knock and then look at my scan and it shows 42* spark with 4-5* knock. I can not figure out where that extra timing is coming from. If it wasn't adding that extra timing there would be no knock. Can someone please point me in the right direction?

    4-2-20 2nd knock.hpl
    2-20-20 trim and slight knock.hpt
    2017 Buick Regal Sport Touring 2.0t

  2. #2
    Tuner in Training
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    May 2019
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    did you check your fuel?or maybe your making your timing to higher that's the causing you a knock.Its pulling a timing on it.

  3. #3
    Thanks,

    Fuel seems to be good in those areas. My Timing is set much lower than what the cars putting out. I tried pulling timing but it still adds on top of that. I need to figure what is adding to it.
    2017 Buick Regal Sport Touring 2.0t

  4. #4
    Tuner in Training
    Join Date
    May 2019
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    46
    did you tried to adjust the main timing maps?or maybe its just like a false knock that giving you.

  5. #5
    I have adjusted the main timing. It may be false knock. My transmission settings are somewhat aggressive. I still don?t understand why the spark is way higher than set.

  6. #6
    Tuning Addict 5FDP's Avatar
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    May 2012
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    Rogers, MN
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    I'm going to guess that it's something to do with the EGR system. We can't see that table and it's possible there is a spark correction table that is adding timing based on that. It may be adding additional timing over the 40-44 degrees in your high octane table.

    Try unplugging the EGR and see if timing stays with what the high octane table has in 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.

  7. #7
    Thanks 5FDP.

    I have the EGR deleted. The plug is being used to give me AFR readings for HPT. I will look through to see if there is anything related to that.

  8. #8
    I don?t see anything EGR related besides the EGR diagnostics which have to be on in order to read the AFR I believe.

  9. #9
    Advanced Tuner ZeroBoostBuick's Avatar
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    Aug 2008
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    S.W. Ontario Canada
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    This is typical of 3800 ecm adding timing when cruising at highway speed.

    Scan cylinder airmass so you can precisely plot and adjust the timing in the corresponding boxes.

    It's not a big deal to see a little KR at cruising speed and lower RPM.

  10. #10
    Thanks Buick!

    I will try to research how to adjust timing based on cylinder airmass. Do you know of any links?