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Why is my car knocking at randomly rpms?

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Old May 4, 2012 | 02:06 AM
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OMGls1jz's Avatar
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Default Why is my car knocking at randomly rpms?

Well guys, I logged my car numerous times today and found out that I have knock. The knock isn't consistent, it appears at random rpms and random gears. Sometimes it will show up in 2nd and 4th and sometimes it won't show up at all in both gears. But its pretty consistent in 3rd gear. When it shows up in 3rd, the rpms it shows up in isn't consistent. I'm starting to think my exhaust could be too loud because i have dual cutouts on my ory or my y pipe is hitting the floor board. what do you guys think? check out my logs and let me know what you think

thanks, Toua
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Old May 4, 2012 | 06:49 PM
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False knock is possible, loud components or the sensors themselves becoming loose in their mounts.

Keep working with it but if you're sure it is false knock then instead of numbing the sensors, reduce the amount timing they can pull and the rate of retard ramp out. That way you can still monitor knock in the future.
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Old May 5, 2012 | 06:26 AM
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Do you have the ability to modify the ignition timing? If so I would suggest pulling some timing out where you're having the issues, and seeing how the knock sensors respond. It appears to me like it's always happening right around peak torque, which I would expect to see. More confusing to me is your bank one oxygen sensor that's hanging at 500mV's. What's up with that? Maybe a dumb question, but what kinda tune is on your car?
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Old May 5, 2012 | 09:15 PM
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Its a sd tune my buddy did like two years ago and I already pulled quite a bit of timing from it. I actually pulled enough where its back to stock timing and i'm pretty sure on stock timing no car should be knocking unless boosted
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Old May 6, 2012 | 06:06 AM
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Originally Posted by OMGls1jz
Its a sd tune my buddy did like two years ago and I already pulled quite a bit of timing from it. I actually pulled enough where its back to stock timing and i'm pretty sure on stock timing no car should be knocking unless boosted
Oh... OK. Perhaps the timing map I was comparing to wasn't factory; it seemed to be much less aggressive. Also I don't think it's fair to assume that a car running factory timing isn't going to knock especially when other items have been manipulated. That being said I suggest trying to figure out why your bank 1 oxygen sensor is sitting at half a volt, and would still pull out even more timing where you see the knock. If nothing else it's an exercise to help prove whether or not the knock is real.
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Old May 6, 2012 | 07:46 AM
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Stock timing is Ussually too much in alot of areas. So don't assume it needs more timing everywhere.
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