lght spd

My 2005 base model C6 with LS2 pings really bad above 5K RPM.
I've been told by a reputable tuner shop on this board that it is more than likely bad gas. Well I have put fresh Chevron 91 octane gas and Lucas Octane booster in with no change. The engine is painfully factory with 84,000 miles on the clock. Only Mods are a cat back exhaust and a K&N FIPK filter and factory tune. Plugs, Wires and Coils I think are original.
Any ideas would be appreciated.

Brandon619

Do yourself a favor and replace the spark plug wires with some quality Taylor wires and NGK plugs. I bet it will run smooth.

truckplay

when did it start? Bad gas could do it but after a refill, it would be gone. Unless the car has been tuned or the engine is running hot, your problem is likely ignition. I would change plugs and wires also wash out the Mass

rpmextra

Do you have HPtuners? If you had a drive log I could try to see what's going on.

It's definitely a ping and not a misfire right?
Any codes present.
those plugs are more than due btw

lght spd

Car runs at normal temp at all times. Never been tuned with a hand held or aftermarket software. Since I don't drive the car more than 1000 miles a year a tank of gas can go months before i go through a full tank. I agree plugs and wires wouldn't hurt at this point. I'm curious what the lifespan of the coils are? Are the rated by mileage or X amount of years?

lght spd

No codes are present.
I'm thinking its pinging because below 5k the car runs as new & smooth as the day it came off the dealership lot.

rpmextra

Coils are pretty tough. You could try spaying a little water on them and check for arcing.
The reason I mentioned hptuners is that you could record the issue as it happens and with that file, I could better see what is happening.
Maybe pull a plug or two and see what they look like.

dentalfloss

Normally if an engine is going to ping , it will ping in the lower rpm's under a load and you can here it, then as the rpm's rise the ping will go away because of less load and you wont here any. In my opinion even if it pinging at 5k you should not even be able to here it and it's less likely like I said. Maybe you are hearing something else.

realcanuk

Check the cats...........

dentalfloss

Yes, clogged cats would tend to restrict exhaust more so in the higher rpm's. Good point.

rpmextra

maybe get us a sound clip?
Cats was a good point too

KB9GKC

Hello,

Likely carbon buildup in the engine from being babied too much!

Carbon buildup retains heat and will prematurely light off the fuel charge before the plug lights it off.

An old trick to get rid of carbon deposits is to inject hot water very slowly into a running engine while revving. This effectively steam cleans the internals and removes the carbon deposits.

I've done this many times over the years with positive results.

Good Luck,

Douglas in Green Bay

dentalfloss

I am thinking with these new modern engines with electronic spark and fuel delivery design's, it is less likely.

Joe_G

The car, particularly with the stock tune, will reduce timing before you hear knock to prevent knock. And there are two tables, a premium fuel spark table and a "bad gas" spark table that the car will revert to the lower table if it detects too much knock due to bad gas.

Take a video of what you are hearing and post it to get some good opinions.

I cannot imagine it's pinging with the stock tune in this car as the car will prevent that from happening. I'm wondering if your aftermarket exhaust is hitting the frame or suspension when you are at WOT causing the noise. When I installed headers they were hitting the pinch weld on the right side and it sounded like a knock but wasn't. I bent the pinch well and all is fine. Make sure your exhaust isn't loose, push it around and make sure you don't hear any clunking.

rpmextra

Great points Joe.
Another note, if your exhaust does knock on something, your knock sensors may pick that resonance up as a knock, therefor causing the timing to be retarded and robbing you of power on false negatives

lght spd

All great points! This gives me a few things to look into.

I appreciate it.

LD85

i hope you already did this and forgive me if I'm late to the party but.....Absolutely put some 92 or 93 in it, gas can only sit for so long before it loses potency

Vito.A

CA only has 91 octane available. You can add 100 unleaded race gas to increase the octane above 91.
Could the knock sensor be bad?

Guard Dad

I had a knock sensor go bad on my LS1 Camaro, any chance it's a knock sensor?

schpenxel

OP: Pickup a can of torco from Amazon or wherever. It's one of the few octane "boosters" that actually work. It will turn your plugs an orange'ish color, so don't freak out if you see orange plugs down the road.

My car, 100% stock, had a bit of knock retard at higher RPM's/loads. Same on my truck. No idea why, but it doesn't surprise me that I'm not the only one.

Knock learn factor will create a "mix" between high and low octane timing tables that leans more towards low octane each time it detects knock, then slowly shifts back to high octane the longer it doesn't detect any knock. It's not an on/off switch from high to low octane timing tables like a lot of people think.

Agree on checking for things moving around.. the knock sensors are EXTREMELY sensitive. I've heard the heat shields on my exhaust make a noise before and saw the knock retard values go nuts because of it. It doesn't take much.

They are cheap and not bad to replace.. just do not over torque them when you tighten them up