02fbody35th

why does my 02 camaro m6 ping at high rpms only when it is hot out. the car is completelly stock and i always run 93 octane. it doesnt really do it when it is cooler or night time. also i just cleaned the MAF and seafoamed the engine so i know it is neither of these things. what can i do please help!!!

fleetmgr

Probably time for new knock sensors.

02fbody35th

actually that is what i thought so i replaced them with no results

thechef

iTrader: (13)

needs a tune, get it to a tuner with a dyno

LS6427

iTrader: (2)

Could be a few different things, but your problem sounds 100% exactly what mine did awhile ago. Your "pinging" is detonation.

Not knowing a whole lot about your engine, I had exactly the same symptoms as you about 5 years ago. Nobody could figure it out. I heard every idea how to fix it and nobody had it right.

In my case it was bad valve seals in my heads, allowing oil to get pulled through them and into the cylinders for months or maybe years straght. I would leave a little trail of smoke any time I went WOT from a cruising speed, then slowly that trail would clear up as I kept accelerating at WOT. Maybe you have that symtom too....this causes burnt oil to build up on the pistons constantly. Or maybe you do not have that symptom yet, but still have leaking valve seals....

This was why I would only get detonation when it was really hot outside and the engine temps rose just a little more than normal. At night, or in the winter months, no problem at all, the engine stayed cool enough to just barely not reach that temp so it would not detonate. And I also always use 93 octane.

The other thing it could be is that your PCV system is sucking in way too much oil and your pistons are getting coated with oil and its getting thicker and thicker. Sea Foaming or MCCC will do absolutely nothing to clean a piston that has burnt oil on it.

Those two things cause pistons to get coated with a layer of burnt oil over time.

So...when you have burnt oil building up on your pistons, that burnt oil heats up as "hot spots" on your pistons. It causes the fuel air mixture to combust before the piston reaches top dead center. (pre-ignition = detonation)
It ONLY happened when it was a hot day or I was really driving the **** out of it and the engine got a little hotter than normal. Never at night or when it was cool.

Another tell tale sign of bad valve seals....raw unburnt oil on your spark plug threads. So remove 2-3 from each side and check for that. I had raw oil on all 8. Also, that raw oil drips down onto the pistons after engine shutdown and just bakes on the piston surfaces too......more burnt oil build up.

So...THE FIX, for me anyway. Rebuild the heads. So when my friend and I removed my heads in my driveway the pictures below are what we found. And we didn't expect to see my pistons like this, I was just going to get my heads rebuilt.
I had them rebuilt, I cleaned all those nasty *** pistons, which wasn't easy to clean. I had to scrape them all separately with a razor. No chemicals would do a thing to soften it up. Took me hours.

I put the newly rebuilt heads on and fired it up. Went for a radical *** drive for over an hour, got it hot as hell. Felt like I bolted on 40 more horsepower and it wouldn't detonate no matter how hot it got or how hard I got on it. Its been prefect ever since.

Not saying its your issue, but the sympoms are 100% exact. So, pull the plugs to check for raw oil, if its there, you have bad valve seals. Depending on how long they've been bad is how much oil has built up on your pistons. So, just a thought for you, its a free check to rule it out.

Good luck.......it drove me ****** nuts for months trying to chase this damn probolem. Its because that cloud of smoke wasn't apparent when I went WOT in the beginning, as the valve seals got worse and worse and let more oil get sucked through when I nailed the pedal, did I start to say "hey, what the hell is causing that now." Well, it was tool late by then, the valves had been leaking oil for months or maybe years, who knows.

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02fbody35th

huh, i will deffinatly check that out. thanks so much for the detailed reply. i havent seen any smoke come out the tail yet but like you said it might just not be apparant yet. Do you think i can put a cooler thermostat and maybe a cooler spark plug for now to get the temps down until i can afford to do the heads if they are the problem. do you think that will work?

LS6427

iTrader: (2)

Well, I'd hate to see you spend any money thats not needed, because I'm not saying that you have this same issue I had. But yes, if this is the reason you are detonating, then the cooler it runs the better. If you do have burnt oil built up on your pistons....Heat is the killer.

Does it happen on hot day at part throttle too, like accelerating casually from say 30-50 maybe just to pass someone. On hot days....

As far as I know...the only reason an engine will detonate is because the fuel/air mixture lights off before the piston reaches top dead center on its way up during the compression stroke. If thats true, you are either using too low of an octane gas and causing pre-ignition (which you said you're using 93, and thats good up to a 12:1 compression engine in hot Florida weather) or you have pre-ignition from hot spots on the pistons ignited it too soon. I think someone told me back then that hot spots can be cause from burnt oil build-up like I had and a couple other things like pitting in the cylinders or something, I can't remember.

Detonation from a bad tune, or being out of tune.....I don't know, maybe....

.

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02fbody35th

well i know their is no tune in the car it is all stock, and i dont really have a proble during regular driving or even if i get on it a little, it is only when it is wot and nearing redline, and only on hot days. it has to be oil build up i dont know what else it could be

LS6427

iTrader: (2)

Pull the plugs and check them for oil, thats the next easy step. Next thing would be to get a leakdown check done and that will tell you if your valve seals are leaking.

If your tune is stock, its not a tuning issue. Tunes don't change.

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LS6427

iTrader: (2)

You know, also, the MAF is only used during cold start-up and later on when you go WOT it will then come into play again. Even though you cleaned it, it could be starting to go on you. Very easy to rule it out for free. Go buy a stock new MAF from any parts store, hook it up and go for a run when its HOT out. If it fixes it your done. If not, take it back for a refund, tell them it did not fit because someone modified your intake and lid sizes. I've done that twice, just make sure its very clean. Tell them you never even got it to fit to start the engine.

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02fbody35th

good idea on the maf i will try that. also i pulled all the plugs on the driver side bank and they all looked good. bone dry with a slight brownish color. i didnt pull any yet on the passanger because of the hassle to get to them but i will later on.

LS6427

iTrader: (2)

Also, hold the throttle blade open and look into your intake with a flashlight, see if its wet with pooling oil in there.

But the MAF thing may be the issue if oil doesn;'t show up anywhere.

I think bent valve(s) can also cause this.

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fuseone

have you checked what the fuel trims are like at wot?