i have an 02 z28 M6, at high rpm only at wot the engine pings. I tried everything, full tune up, 02 sensors, knock sensors,and even swithched the pcv system to the ls6 style under the valley pan for less oil consumption. Still their. PLEASE HELP!!!! I know thier are some ls1 gods out their that can help. Thanks

 

Is it only pinging when the outside temperatures are high? How about in winter? Any pinging then?

You can always try some higher octane fuel or back off your spark advance.

What kind of timing do you have at WOT? Mine runs great with just 22 degrees at WOT, but I am running a little higher compression.

Check those items out and we might be able to help you out a little more.


..WeathermanShawn..

 

Im having the same problem in my 2000 z28. Its got 158k miles, so at first i thought maybe the plug wires, that didnt help. Then I changed my plugs (tr6 for nitrous) and i thought that did the trick at first, but then last night it was doing it again. I was going to have my coils checked, but apparently you cant just check them, all you can do is switch them around and see if the problem follows. But i dont know which cylinders is pinging. I have a 100 shot, but it pings on motor, so ive held off on going to the track. Ive got a predator tuner, and have the timing backed off at WOT 4 degrees, and even with this timing being retarded, its still pinging on motor!

Where else should i check? Its only been pinging at high wot rpm since earlier this spring, so it hasnt been just the hot weather.

 

I would sea foam it. Oil and gas really dont combust well, And I would run a catch can set up. Oh hows the fuel pressure? WOT puts a demand on the fuel pump a clogged filter will hinder it also the filter in the tank.

 

Ive got the problem remedied for now i think. I've got the timing back as far as i can with the predator alone, which is 23-24 degrees. at this setting, i have 1 or less degrees on KR (sometimes 0), whereas i was at 1-2 before, and around 3 at stock setting.

I will seafoam it too, and see how that does. I also checked my mass air, and it looked clean. The entire fuel pump module and fuel filter are about a year old.

But what i dont understand, is why this came about by itself. It used to run great the way it was only 6 months ago, and now i have to pull all the timing i can out of it to keep it from detonating. I also switched to shell gas, instead of where i had been buying it.

 

i have 2001 SS with same problem, i also have done EVERYTHING to help but no luck. it is definetly a timing issue! if i run 100 octane problem solved, but who can pay $6 a gallon. i think a bad sensor(somewhere) may be causing it. im getting a dyno tune soon, let ya know.

 

I almost wonder if the quality of fuel now days has gone down. Perhaps buying gas at different places could create different patterns of detonation or no detonation.

 

i think you hit the nail right on the head, i hear of guys with older cars that use to run on leaded having big problems because our gas is getting more diluted with ethanol...

 

you are both right, where u get u'r GAS does matter. even then if u get it from the same place everytime, every batch of gas will not be the same.

 

Im just going to start my own refinery....

Until then I guess I'll keep switchin up where i buy. Any ideas on who carries good gas?

 

I just got my car dyno tuned and was having the same problem. I was getting oil into the intake and detonating up top. Tuner (Geoff) at Next Level Performance suggested I get a catch can and re gap my plugs to .40".


He also stated that he has luck with BP gas.

 

this is what i did to battle problem, 2 cans GM top engine cleaner, elite eng. catch can, pcv valve ,new factory plugs,flushed coolant and still i had the issue. as i said before the ONLY thing that solved problem is 100 OCTANE. which means it's a timing issue, there is nothing left.

this is a list of what causes KNOCK.
1-fuel octane is below engine requirements,or lean ratio
2-spark timing is advanced excessively
3-engine coolant temp/ or inlet air temp is above normal range
4-sparks plugs of incorrect heat range(too hot)
5-hot spots in combustion chamber, such as carbon

 

Mopar makes some stuff called Combustion Chamber Cleaner and I've read good things about it. Do it kinda like seafoam but you spray directly into the throttle body and it foams up onto the intake runners supposedly dissolving the carbon buildup...

Fuel is your problem. I would look into possibly buying a 55gal of Xylene (117 octane) or Toluene (114 octane I think) if you know someone who owns a wholesale paint place and can get it for cost or close to it (should be around 300/55gal. It's cheaper doing that than running that 5-8 dollar/gal race gas that's 100 octane.

 

What do you know about your fuel pressure at WOT?

 

good on my car, i even got to play with a Genisis diagnostic tool, my friend works at a chevy dealership. anyway my longterm fuel trim was fine and my computer pulls timing up top, but i guess not enough. im only a shade tree mechanic, so i couldnt spot anything with scanner, thats why im going to get DYNO tune where they can lock out engine timing. and hopefully find the problem