I've got a 2001 Z06. I noticed the other day in second gear at WOT that it made a funny sound. It wasn't really loud like a backfire, but kind of like something loose or maybe rattling / exhaust, not really too sure. The only things i've had done is a Vararam intake and Magnaflow X-Pipe. Now I don't notice the sound in 1st gear, or at idle when revving the engine.

Anyhow, i've heard people discuss detonation on the forum and how bad it is, but I don't think i've ever heard it before. Is there a sound file out there with "sample" detonation sounds, or if somone could describe it to me.

I can "always" get it to make the sound however, it isn't sporadic?

Thanks..

 

Detonation is that pinging sound you used to hear on older cars. I am not saying yours isn't doing it, but the computer in newer cars does its absolute best job to make sure it doesn't happen. It will retard the timing to prevent detonation. If you can consistently reproduce the sound, you may try to take it into the dealer and take a tech for a test drive and see what he thinks. Good luck!!!

 

It has been described as sounding like "marbles being shaken inside a can"--not good! Have you changed fuel brands/stations/octanes?

Btw, I wouldn't waste money on OTC octane 'boosters'. They are almost worthless.

You may have a malfunctioning knock-sensor? I had mine go 'out' on my 1991 Camaro Z281LE while driver's schooling it at Road Atlanta a few years ago. I would get it checked.

Here is some good info on detonation:
http://zhome.com/ZCMnL/PICS/detonation/detonation.html

Dan

 

Could it be drivetrain noises?

My clutch/drivetrain makes funny noises but they're more sporadic.

 

Detonation or ping sounds like a muffled rattle. To me, it's more like small pebbles in a can than marbles. Basically, the cylinder(s) is/are firing too soon- as if the engine had too much spark advance. It's not necessarily gear specific, and it tends to be more noticeable in higher gears where the engine can be loaded more.

It's aggravated by high engine temperatures. Low revs in a gear that's too high (partial throttle lugging up a hill, for example) can precipitate the condition. Bad fuel or low octane also can cause it. Don't mess with octane boosters, though. It can be a serious problem if it's constant despite engine speed or throttle opening, otherwise, it's more of a nuisance or an indication you're not getting top performance for some reason. Fouled or carboned spark plugs will also cause it, btw.

Try some different brands of fuel and whatever the top octane available is. Fuel formulations vary from location to location and season to season. It may just be a season transition deal. I've recently heard something that sounds like detonation in mine (part throttle, low rpm), and I'm still experimenting with fuel.

Then again, it could merely be something that sounds like detonation and isn't.


[Modified by rwd, 4:32 PM 4/2/2003]

 

there is a service bulletin on "pinging" in late model GMs the knock sensors, under the intake get corroded and dont respond correctly especialy on engines that get washed regularly.