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Thread: Identifying false knock?

  1. #1
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    Identifying false knock?

    Long time lurker, first time poster.

    Car: 2005 GTO, 6.0l LS2
    Mods: Fast102 intake, Kooks stepped headers
    Fuel: Shell 93 TT (only)
    Wideband: idk, the AEM one with CANBUS

    I've been dipping my toe into tuning the last few months, dialing in VE and MAF using stft, and using an AEM wb to do the wot stuff. The whole time I kept checking the knock retard histogram to make sure I was still safe when making fueling changes, and because I'm a noob I didn't realize that no numbers at all is not the same as no knock retard-- I hadn't been logging it the whole time.

    So when I started logging it I right away was getting up to 5 degrees of retard during times when I wouldn't expect to be getting knock, not that I really know. So as a test I pulled 5 degrees out of the whole high octane base table thinking that if I still get some kr then I can rest assured that it's just overly sensitive sensors or at the very least it's coming from somewhere else besides genuine spark knock. I've been posting about it on ls1gto but the new forum platform won't let me post logs.

    maf13.hpl - the wb wasn't logging for this log, but I don't suspect that it was lean during the kr
    maf15.hpl - I did get a couple degrees of kr during a wot pull at 11 minutes in, so that's possibly genuine
    maf16.hpl - same, couple degrees during wot pulls, these look like they could be real to me
    maf17.hpl - back to kr at what seems to me to be weird times, 6 minutes in. Just set the cruise control it looks like but the map goes up and it looks like it's anticipating knock. 8 minutes in, 5 degrees of kr at the beginning of a wot pull.
    kr1.hpl - 5 degrees pulled out of the high octane table, now it's spiking the kr but it doesn't slowly trail off like before. Also I started logging more knock pids, but for some reason my chart reads half the amount that the channels list shows. I wish when you were choosing a pid that it had the sensor number next to it so you knew you were choosing the same one (probably not using the correct terminology there)
    kr2.hpl - same, up to 6 degrees of kr despite pulling 5 degrees out of the whole base table
    And I went ahead and attached my latest tune in case that would be helpful.


    So does most of this look like valid knock? If not, what does valid knock look like/when does it occur? How do I get rid of it? At this point I've finished dialing in the fueling so I loaded the last tune with the stock spark table in and have just been taking it easy. Many thanks in advance
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    Last edited by evsnova74; 05-13-2022 at 07:56 PM.

  2. #2
    Tuning Addict blindsquirrel's Avatar
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    Disable Burst Knock (ECM 12765).

  3. #3
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    In engine>spark>burst knock retard I shifted the base vs cylairdelta over a couple columns and took 10% out of the mult vs RPM table, I don't think IAT or ECT are impacting it in my case.

    bkr1.hpl - still got kr, nothing from the burst knock pid though.
    bkr2.hpl - same
    bkr3.hpl - I pulled 5 degrees out of the base high octane table again, still got kr so idk at this point. It still doesn't seem like real knock.
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  4. #4
    Tuning Addict blindsquirrel's Avatar
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    Did you zero out the burst knock table or not? You don't need it even if it's not the source of this exact current issue.

  5. #5
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    Well no, I just desensitized it a bit as described above. And since it wasn't registering any burst knock retard this time, that essentially disabled it. But just in case I went ahead and zeroed it out and got another log, still getting kr. And that's with 5 degrees pulled out of the base table so I don't see how it's real knock at this point.
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