Compression and Pinging
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From: Yorktown VA
Compression and Pinging
Just bought an '04 CE coupe. Prev owner stated heads were mildly ported and shaved .030". What is the stock compression and what might it be now? He also said the it had been tuned but it starts pinging pretty bad at about 3000 RPM. Running 93 octane. Shouldn't a tune have corrected this? Should I run a fuel additive?
Last edited by Kaseman; Oct 8, 2006 at 12:04 PM.
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From: At the beach in little Rhody
Sound to me like the installed tune needs to be re-examined. Have you had it at the dealer at all recently, usually a tuner will correct this situation. Wonder if the dealer might have flashed out your custom tune. Otherwise start examining your usual culprits, vacuum leak, etc.
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From: Yorktown VA
Has not been to dealer. I'm really unclear as to weather a tune was actually done. He said it was dyno tuned but the wideband O2 wasn't working. The he said it was street tuned. I don't know. 
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From: At the beach in little Rhody
You really need to get it to a good tuner to check this out, also carbon will cause some pinging. Might be worth the decarb procedure as a start. Also, using FP60 will help keep future carbon build-up in check if that is your problem. These cars pull in a lot of oil from the PCV system, so carbon could be an issue.
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From: Yorktown VA
Thanks vettenuts. The pvc has an oil catch can in line. I think it is most likely the tune. It has a vararam that was installed maybe after the previous tune. I have seen many threads where this was the concern.
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From: At the beach in little Rhody
Originally Posted by Kaseman
It has a vararam that was installed maybe after the previous tune.
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From: .... NJ
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St. Jude Donor '05 thru '19
Originally Posted by Kaseman
Thanks vettenuts. The pvc has an oil catch can in line. I think it is most likely the tune. It has a vararam that was installed maybe after the previous tune. I have seen many threads where this was the concern.
The i read that the vararam can shift the a/f ratio lean, you probely need a re-tune.
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From: .... NJ
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Originally Posted by vettenuts
I would think the 04 might be more sensitive to this as well, isn't the MAF screenless or is that only the Z06?
My 04 LS1 has the screen.