C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Need help with detonation problem

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Old 04-19-2005, 10:00 AM
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ICANTDR55
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Default Need help with detonation problem

I have the zz3 engine and every sense the trans change, I have picked up this detonation problem. I tried the 95 knock sensor and rapped it with teflon. I recheck my timing and it is set at 8 degrees and 28 degrees @4000rpm before it was 32@4000rpm,I tried 26@4000 and the thing still detonates. Temp run at 180-182 degrees. The bolar system is loud and the computer read out says it is picking up a knock. Could this be the problem and if so how do I solve it? Oh fuel Pressure 42psi. 1987 corvette. Has tpis chip that was burned for the stock engine

Last edited by ICANTDR55; 04-19-2005 at 12:03 PM.
Old 04-19-2005, 11:37 AM
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CFI-EFI
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What year? Any codes? That teflon tape on the knock sensor may prevent it from grounding properly and the ECM/ESC may not know it's there.

RACE ON!!!

Last edited by CFI-EFI; 04-19-2005 at 11:40 AM.
Old 04-19-2005, 12:07 PM
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ICANTDR55
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It is a 87 vette. I also have the tpis chip that was burned for the stock engine still in the computer. You think that would cause the problem?
Old 04-19-2005, 01:49 PM
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CFI-EFI
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*I* wouldn't expect so.

RACE ON!!!
Old 04-19-2005, 02:21 PM
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JAKE
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[SNIP=ICANTDR55]. The bolar system is loud and the computer read out says it is picking up a knock. [/SNIP]

What's a bolar system?

Jake
Old 04-19-2005, 10:09 PM
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DVNCI
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Originally Posted by CFI-EFI
What year? Any codes? That teflon tape on the knock sensor may prevent it from grounding properly and the ECM/ESC may not know it's there.

RACE ON!!!


I "think" the factory manual says something about not doing this???
Old 04-20-2005, 01:33 AM
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olman
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Might check the EGR. Has this engine ever ran with out pinging?
Old 04-20-2005, 02:23 AM
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Morley
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Originally Posted by JAKE
[SNIP=ICANTDR55]. The bolar system is loud and the computer read out says it is picking up a knock. [/SNIP]

What's a bolar system?

Jake
Borla
Old 04-20-2005, 04:33 PM
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JAKE
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Originally Posted by RUKWKR


I "think" the factory manual says something about not doing this???
It depends on the year of the engine.

The shop manual for the 86 specifically says TO USE thread sealer, such as soft sealing tape on the ESC knock sensor threads.

Jake
Old 04-20-2005, 04:38 PM
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gbody5
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Maybe double check all the trans to engine bolts, make sure there is not some rattling going on that is setting of the knock sensor?
Old 04-20-2005, 05:05 PM
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JAKE
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Are you actually HEARING detonation/knock, or is it just showing up on your scanner as knock retard/knock counts?

What A/F ratio are you seeing? If you don't have those numbers, what is your 02 voltage reading when the detonation occurs?

Did you move to the ESC knock module that Gordon recommends to help eliminate false knock conditions? Part # 16038331

If you are ABSOLUTELY SURE that it's false knock, you can wire in a resistor to the ESC which effectively disables the knock sensor but does not cause a code to set.

Jake

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