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Thread: False Knock?

  1. #1

    False Knock?

    I seem to be getting what I think is false knock. I have never been able to hear an engine pinging. Maybe I'm going deaf?? The setup is a turbo 5.3 with a mild cam. The scanner detects knock every once in awhile but I never hear anything and it also occurs at low load part throttle or no throttle at all. I do have burst KR turned off. I have attached an example log and config if anyone wants to take a look. I have also attached my tune if anyone is curious. Thanks
    Attached Files Attached Files

  2. #2
    I should also mention the car is running E85.

  3. #3
    Tuning Addict 5FDP's Avatar
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    Not that this has to do with knock but you have been doing all your tuning with the computer thinking this engine is a 6.0 and not a 5.3. So some of the fueling is already off because of that.

    Nothing is rubber and you don't have blown out engine mounts right?

    No pending knock sensor codes? Any clue on their condition? Like are they factory sensor, been replaced with new AC delco parts?
    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.

  4. #4
    Advanced Tuner Boost's Avatar
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    Quote Originally Posted by 5FDP View Post
    Nothing is rubber and you don't have blown out engine mounts right?

    No pending knock sensor codes? Any clue on their condition? Like are they factory sensor, been replaced with new AC delco parts?
    This brings me to a (relevant/on topic) question about my car. Have an aggressive setup for a daily driver - solid engine mounts, full spool etc...

    I am monitoring and eliminating all knock under all conditions that is more than 1.0

    How would false knock look on a graph as opposed to real knock?? Some kind of saw tooth pattern right?

    I am thinking I have real knock because it only comes in after driving for quite a while (cylinder temps/pressure?)

    Nothing audible usually but so far it seems to have reduced significantly after using top engine cleaner.

    I also seriously plan on replacing my stock heat range E3 plugs with TR6s, even though I'm NA and stockish - because I drive aggressively in a hot climate and want to use more timing for power without knock.

    Hope it makes sense / works...

    I have positive previous experience using colder plugs

    '12 Caprice PPV 6.0 L77 - daily transportation
    8.7 @ 84 (1/8 mile) bolt-ons

    '02 Silverado RCSB 5.3 L59 - regularly street driven
    8.2 @ 86 (1/8 mile) stock cam and spray
    8.6 @ 84 (1/8 mile) cam and heads no spray

    Our YOUTUBE CHANNEL featuring the Silverado

  5. #5
    Senior Tuner cobaltssoverbooster's Avatar
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    I make a tune on 91/93 pump gas and tune it to where the ignition is smooth and maybe shows active kr up to 1-2* under moderate load (i dont allow questionable detonation to exist under heavy load). Then i throw some VP MS109, VP110, or C16 whatever i have laying around. i do it with low fuel level of 91/93 of course so that when i add a small amount of the expensive stuff i end up with a higher octane rating. If you do this and the kr goes away then its real cylinder pressure based. If it stays and its always in the same load range then its likely a harmonic from the mechanical side.

    i have also done it with E85 from a pump but i have to drive 2.5 hours to get to one of those pumps and shipping the fuel to my shop is lazy and is only 10 minutes from where i keep my cars. I would mix for a ratio around E20-30 (20-30% ethanol content) shouldnt throw the fueling off too bad and should raise the ignition kr threshold enough to separate true from mechanical knock.

    the best way which i save for last is expensive but probably the best way and that is to invest in some knock ears.
    https://www.haltech.com/product/ht-0...nock-ears-kit/
    https://www.motorsportselectronics.c...nt=13654731524
    2000 Ford Mustang - Top Sportsman

  6. #6
    Advanced Tuner Boost's Avatar
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    Quote Originally Posted by cobaltssoverbooster View Post
    I make a tune on 91/93 pump gas and tune it to where the ignition is smooth and maybe shows active kr up to 1-2* under moderate load (i dont allow questionable detonation to exist under heavy load). Then i throw some VP MS109, VP110, or C16 whatever i have laying around. i do it with low fuel level of 91/93 of course so that when i add a small amount of the expensive stuff i end up with a higher octane rating. If you do this and the kr goes away then its real cylinder pressure based. If it stays and its always in the same load range then its likely a harmonic from the mechanical side.

    i have also done it with E85 from a pump but i have to drive 2.5 hours to get to one of those pumps and shipping the fuel to my shop is lazy and is only 10 minutes from where i keep my cars. I would mix for a ratio around E20-30 (20-30% ethanol content) shouldnt throw the fueling off too bad and should raise the ignition kr threshold enough to separate true from mechanical knock.

    the best way which i save for last is expensive but probably the best way and that is to invest in some knock ears.
    https://www.haltech.com/product/ht-0...nock-ears-kit/
    https://www.motorsportselectronics.c...nt=13654731524
    Thank you, sounds good. I am not sure/don't think I can run corn in my stock fuel system. I do have noisy bearings in the a/c, water pump along with the typical stock LS1 racket so perhaps I will start allowing 2.0 max retard in the not WOT areas if it isn't audible.

    I plan on replacing the noisy water pump and getting an ATI balancer so that might help "some".
    '12 Caprice PPV 6.0 L77 - daily transportation
    8.7 @ 84 (1/8 mile) bolt-ons

    '02 Silverado RCSB 5.3 L59 - regularly street driven
    8.2 @ 86 (1/8 mile) stock cam and spray
    8.6 @ 84 (1/8 mile) cam and heads no spray

    Our YOUTUBE CHANNEL featuring the Silverado

  7. #7
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    That Haltech unit, anyone have experience with it? Someone was recently telling me about this concept. Briefly thought about splicing into my knock sensors and plugging them into the radio, lol.

  8. #8
    Advanced Tuner Boost's Avatar
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    Quote Originally Posted by NotSure View Post
    That Haltech unit, anyone have experience with it? Someone was recently telling me about this concept. Briefly thought about splicing into my knock sensors and plugging them into the radio, lol.
    We always used J&S knock sensors from my Haltech days. Then again we're talking F9 / E6K
    '12 Caprice PPV 6.0 L77 - daily transportation
    8.7 @ 84 (1/8 mile) bolt-ons

    '02 Silverado RCSB 5.3 L59 - regularly street driven
    8.2 @ 86 (1/8 mile) stock cam and spray
    8.6 @ 84 (1/8 mile) cam and heads no spray

    Our YOUTUBE CHANNEL featuring the Silverado