False knock???

Discussion in 'Forced Induction - 5.0L V8 Engine' started by SSG 5.0, Apr 20, 2020.

  1. SSG 5.0

    SSG 5.0 Well-Known Member

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    I was having trouble pinpointing my engine knock, but I think I have an idea now. Maybe I’m wrong and I need y’all’s input.

    I added the rest of the vp octanium unleaded octane booster because my knock sensor gave me 20 max knock and thinking my fuel are bad. I got the fuel from shell and Sunoco and shell even made it worse.

    I asked the wife to drive me around so I can take a look at the logs and really look at it because I was really concern. She drives like a grandma really so all of these knocks are from driving normal. I say the knock sensor got happy when she changes lane and made a sharp turn and all of these knock showed up.
    Knock sensor min, max and avg.
    1. -6.17, 41.40 and -0.19
    2. 0.00, 1020 and 1.08
    3. -7.50, 1020 and -0.34

    The car absolutely sounded great, pulls hard and shifts better than it used to as well.
     
  2. TGGT

    TGGT Well-Known Member

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    The negative numbers are good this means the pcm is adding timing. If you are seeing positive knock in a cornering situation it sounds like a header hitting or exhaust
     
  3. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    That’s a damn problem because I have the stock headers. I know the procharger installer lost most of my pins under the fender left and right and probably hitting that area.
     
  4. Roh92cp

    Roh92cp Well-Known Member

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    To accurately rule out false knock you need to data log. You really only need to concern yourself with WOT high loads from 3k rpm to 7k in a safe gear without wheels spins. Driving under normal conditions median to light loads the timing will shift all over.
     
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  5. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    I’ve hit solar, ahl, patriot six, beast, and others and the tireless SheepDog and gave me nothing but positive and knowledgeable members to combat this car. All of them gave me great advice and solutions really. I’m just trying to pinpoint this knock and I can’t believe my car knock like a .50 cal machine gun next to my ear lol.
     
  6. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    When I did a data logged earlier from 1st, 2nd up to 3rd gear, my knock was actually 2 maxed. When I did a couple of 3rd gear pull from 50-80 mph, I saw a 17-20 max knock.

    Also, when I was getting the car tire warmed up and trans 150 F before going wot, my knock hit 9.0 max smh.
     
  7. TGGT

    TGGT Well-Known Member

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    Definitely data log. Keep in mind that with advance track on. The pcm will pull timing
     
  8. Roh92cp

    Roh92cp Well-Known Member

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    Not sure I understand your knock numbers, but if your seeing +9 knock then your in trouble or you got something rattling. I can't understand from your post which it is. If you can data log then I would send that to your tuner and post it here for us to look at. But if your seeing +9 or more and not sure its false then stop what your doing and have it diagnosed by a reputable speed shop.
     
  9. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    I’ve been data logging brother. Turning the advance track is actually a memory now.
    I’ve been watching this car like fly on shit lol.
     
  10. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    I got you boss. Look at this from just driving normal. 451746E4-E0DE-4F85-8FCB-DD0800576C08.jpeg 8C229962-228A-418D-BB9E-41FF017D7198.jpeg
     
  11. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    Everything looks great but not the knock. This car runs like a grandpa on steroids.
     
  12. Nagare

    Nagare Well-Known Member

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    Are you sure the sensors themselves aren't shot? I've never seen anything over like 7 so 41 is crazy, let alone 1020. Are you noticing anything consistent when it reads high? Is your exhaust tight all the way through? Any clamps or is it all welded? If there are clamps, I would make sure the clamp is good and tight and that your bolts aren't backing off at all. Could also be your exhaust rubbing at the tips on the bumper or perhaps something hitting metal closer to the cats/trans.
     
  13. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    You know, when I I changed the factory 3.70 to 3.50 p/c pulley, there’s this little thin washer fell underneath and I couldn’t find it really. I didn’t even think that little thin can can or possibly be a pain in the ass if that’s true.
    Where’s this sensor if I have to change it? My car is only 14k miles because I hardly drive the car.
     
  14. TGGT

    TGGT Well-Known Member

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    I’m not familiar with the sct logging software, but what I will say is that according to your logs your at part throttle. I seriously doubt you are experiencing actual knock. Has your tuner looked at these. Have you looked for sources of potential false knock?
     
  15. OP
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    SSG 5.0

    SSG 5.0 Well-Known Member

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    I haven’t looked into potential knock except that tiny washer that came off fromthe procharger pulley. I changed it and that little shit kept on rolling down.

    Bluebeast told me to remove a spark plug and check. If the plug is white, I’m too lean and if I see a black tip, it’s a false knock.
     
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