Pre-detonation noise
Thread Starter
Le Mans Master
Joined: Oct 2007
Posts: 6,868
Likes: 770
From: Kelso Washington
St. Jude Donor '09, '13, '15
Pre-detonation noise
My C5 is stock and driven regularly, has 109K on the clock but still runs and drives very well.
If I sneak up on the power curve, it does fine. But when I put the fuel to it for max acceleration, I get some pre-ignition noise (rattling sound)around four or five K rpm.
Is this because of carbon deposits or will a good tune help? It's got new plugs and wires and I run premium fuel only.
CAI and aftermarket cat-backs as well.
The noise just makes me cringe....
If I sneak up on the power curve, it does fine. But when I put the fuel to it for max acceleration, I get some pre-ignition noise (rattling sound)around four or five K rpm.
Is this because of carbon deposits or will a good tune help? It's got new plugs and wires and I run premium fuel only.
CAI and aftermarket cat-backs as well.
The noise just makes me cringe....
Safety Car
Joined: Aug 2011
Posts: 4,444
Likes: 408
From: Portland OR
You could have a dead knock sensor. I'm not sure if that illuminates the check engine light.
That said, the knock sensors also have to "hear" the knock before reducing timing to fix it. This might be what you are hearing as well.
A good tune up if it's been awhile is always a good idea.
BTW Greg, bring it by. We can datalog it!
That said, the knock sensors also have to "hear" the knock before reducing timing to fix it. This might be what you are hearing as well.
A good tune up if it's been awhile is always a good idea.
BTW Greg, bring it by. We can datalog it!
Last edited by RonSSNova; Aug 19, 2014 at 04:35 PM.
Melting Slicks
Joined: Sep 2011
Posts: 2,258
Likes: 543
From: Appleton WI
How new are the CAI and exhaust? If new, the car may not have adjusted to the set-up yet or the tune in not correct. Check for codes as others suggested. Is the acceleration weak or strong?
Could also be dirty injectors, dirty MAF, weak fuel pump, or clogged fuel filter. Not sure what year your Vette is. If pre-mid 2003, the fuel filter is a quick and easy change. Buy a Wix brand filter not the AC Delco. (Much cheaper and exact same filter) I'm guessing it is the original and wouldn't hurt to change anyway and an often overlooked maintenance item.
Could also be dirty injectors, dirty MAF, weak fuel pump, or clogged fuel filter. Not sure what year your Vette is. If pre-mid 2003, the fuel filter is a quick and easy change. Buy a Wix brand filter not the AC Delco. (Much cheaper and exact same filter) I'm guessing it is the original and wouldn't hurt to change anyway and an often overlooked maintenance item.
Thread Starter
Le Mans Master
Joined: Oct 2007
Posts: 6,868
Likes: 770
From: Kelso Washington
St. Jude Donor '09, '13, '15
Hmm....interesting....and some possibilities I did not suspect.
It's a 2002. The CAI was on it six years ago and the exhaust has been on for about four years.
No codes. No check engine.
Fuel filter changed about a thousand miles ago. Plugs and wires about the same.
I can accelerate plenty fast without burying my right foot, but when I do bury it, I get this ping/rattle in a certain range rpm.
Could just be crappy fuel too. I usually fill at Costco or Safeway...sometimes Chevron.
Thanks for some ideas folks....appreciate it.
HEY....RON!!....I just realized that was you. Hope you are doing well. I'm still in Beaverton, Rainier on the weekends. What's "data log"? Is that a performance data collection process?
It's a 2002. The CAI was on it six years ago and the exhaust has been on for about four years.
No codes. No check engine.
Fuel filter changed about a thousand miles ago. Plugs and wires about the same.
I can accelerate plenty fast without burying my right foot, but when I do bury it, I get this ping/rattle in a certain range rpm.
Could just be crappy fuel too. I usually fill at Costco or Safeway...sometimes Chevron.
Thanks for some ideas folks....appreciate it.
HEY....RON!!....I just realized that was you. Hope you are doing well. I'm still in Beaverton, Rainier on the weekends. What's "data log"? Is that a performance data collection process?
Last edited by Oh 2 Fun; Aug 19, 2014 at 04:40 PM.
Thread Starter
Le Mans Master
Joined: Oct 2007
Posts: 6,868
Likes: 770
From: Kelso Washington
St. Jude Donor '09, '13, '15
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Joined: Sep 2009
Posts: 1,719
Likes: 4
From: cinnaminson n.j.
St. Jude Donor '14
I'm confident Ron will find the problem?