Greetings - I've a 2007 C6 (Z51) with 10K miles. I've recently begun to hear a pinging during somewhat strong acceleration. I've never lugged the engine and generally hold shifts (6 speed manual) a little higher than most. Usually I hear the ping right off throttle after shifting into 4th and taking off in 1st. The pinging seems to go away in a few seconds.

Yes, I'm planning on visiting the dealer soon but am wondering if anyone else has experienced this.

Keith

 

what octane are you using?

 

You shouldn't hear a ping even with 87 octane. The knock sensor should take over and eliminate it. The dealer should be able to help.

 

Talked to my tuner and they said change gasoline brands, I was using Citgo and Whatever Sams uses, for price.

So I have. Saving 5@ a gallon is not worth the knock, even when it says 93 octane, it's not

 

Always stick with a top tier fuel. I will only use Chevron Supreme in the Vette (as well as our other cars). Shell and 76 will work as well, but if you have a Chevron in the area it's a good way to go.

 

Thanks for the input. I've been using Chevron Supreme. I've been avoiding all the rest. All I can think in reference to brand is that my Chevron dealer might not be actually using Chevron gas. There was a scandal in California years ago where some branded dealers were buying different gas.

However, I suspect I need to see the dealer. That ping can't be safe.

 

detonation=bad

that is all....





oh, see your dealer

 

My '07 z51 6spd also started pinging like yours at about 6k miles. took it to the dealer and he said no codes and use higher octane. Been using 93 octane and changed brands but still pings. Dealer said to use additive. On a new stock car? Shouldn't have to do that. Let me know how your pinging is resolved. I'm furious with chevy right now.

 

There is nothing a dealer can do for pinging, don't waste your time. It's not like the old days when they could tinker with the timing. The programming is fixed, they couldn't change it if the wanted to.

Not true that knock sensors and knock retard stops all pinging. Some pinging is preignition. The mixture ignites before the spark plug fires, retard the timing all you want, makes no difference on preignition.

Preignition can be reduced by:

Clean the carbon out of the engine - Take it for a highway blast and let it rip, repeat, repeat. Then get half a tank or so of top tier 93, like from Shell. Use a different brand than your having the problem with.
Put a bottle of Chevron with Techron Top Engine Cleaner. Parts stores have it in a black bottle. GM dealers parts dept have the exact same thing as a Top Engine Cleaner with Techron. Techron is the key ingredient, that stuff will clean out the engine. Both the Chevron brand and the GM Parts is the same stuff.

Drive for a few days with the top engine cleaner in the gas, then take it out for anout highway blast. Let it rip wide open a couple times.

Check oil. Sometimes a top engine cleaning will really darken the oil if a lot of carbon has built up and removed. I always change the oil after a top engine cleaning.

Then see how it's doing after all that and using a different brand of top tier 93. Still pinging, add octane booster.

I wouldn't even bother with a dealer or getting miffed that something is wrong. Some spark knock is the nature of the beast on a high compression engine. Brand new it was on the edge of detonation. Put on some miles with some carbon build up takes the compression up even higher and now the carbon can have some hot spots. Increased compression and carbon hot spots = pinging. A good top engine cleaning will help.

The fact that the pinging has come on after accumulating some miles is an indicator that carbon build up is the culprit. The timing has changed, but carbon does build up over time. Has the oil been kept fresh and full? Old thinned out oil burns easier and builds up carbon.
The trend toward running super long miles between oil changes doesn't help. Can't tell you how many vette hoods I've opened and the oil is - low, black as tar, and thin as water. Call me crazy for changing my oil every 3K, but my vettes don't knock or burn a drop of oil. Check my oil anytime and it's on the full mark and clean as new.

 

Hum....Thanks for this new information. Now I've got more information. I was hoping I didn't need octane booster. That's I've used in my highly modified engines. Still do. Kinda expensive for a daily driver (my C6).

But I cannot let my new engine self destruct.

Thanks again,

Keith

 

just got back from a 2300 mile trip,and 1200 plus was on citgo reg fuel,no ping,no problems,28-30 miles to the gal,did not see any difference when using premium,I have yet to check the last tank of premium though.

 

Carbon build-up may well be your problem. VERY common in C5s too. You might want to go to the C5 forum and do a search for: de-carbonization.

 

Knock sensors do go bad. My daughters Suburban was defective and set a code. I canceled the code several times only to have it come back. We replaced the sensor, reset the code and a year later the code and check engine light have not returned.

 

I wouldn't worry about the engine self destructing. A little ping is very common in high compression vette engines, most just don't pay close enough attention to notice it. It's the extreme spark knock that sounds like marbles in a tin can and loud crunching when getting into the throttle hard, that over time can cause damage. But just that little bit, where you think you kind of hear something and then if you pay real close attention and mess with the throttle just so, you can hear a little pinging - that's nothing, heck I can make my Silverado do that.

And just about every vette I've ever had a scanner on I've observed the knock sensors picking up knock.

I agree on a rare occasion a knock sensor has gone bad and turns on the check engine light. But in this case, the symptom is audible knock that goes away quick, and no check engine light. So many vettes do the exact same thing, that's why I'm leaning toward nothing is wrong and maybe a little top engine cleaning out the carbon will help. A trip to the dealer is a waste of time and no need for them to be joy riding your nice car. Tons of people on here have written about the exact same thing and them come back to say the dealer did nothing but drove the car around and then said to switch gas brands.

 

Mitchrider, do you think a car with only 8-10k miles could actually have a carbon problem? Do you know if the chevron with techron is the same as seafoam? Thanks

 

It absolutely can. The combustion chambers and quench areas in these modern engines are so tiny, the pistons are unbelievably close to the head. And it's not like the engines are really carboned up like the old days where you scraped pistons off with putty knives, today it's just a slight build up that with compression ratios so high can cause a little knock. Even brand new engines with pristinely clean combustion chambers, it's not uncommon to get just a little spark knock.

Trucks do the exact some thing. My 03 Silverado gets putzed around driven like an old man all year and every once in a while when I do get into the throttle harder I hear some spark knock. I'll put the Techron cleaner in a tank of premium and take it out on the highway. I'll adjust my rear view so I can see the tailpipe, and the first time I floor it it gives out a big puff of grayish/blackish smoke. Then everytime I floor it after that, the exhaust is clean and it stops spark knocking. That tells me, it blew the carbon out.

If you drive real easy a lot without flooring it for quite a while, there will be a little carbon build up.

I think Seafoam is different, but I've heard good comments about it. But I do know the GM Top Engine Cleaner and Chevron w/ Techron are both the same and very effective at cleaning out the carbon. I know GM tested many different top engine cleaners and went with Techron.

I'd put a bottle of Top Engine Cleaner in the tank, drive normal that day. Then the next day, take it out on the highway and give it some full throttle runs through the gears. If you really want to know if it had a little carbon, have someone follow you and watch your tail pipes the first time you floor it. If there's a puff of dark smoke, it had a bit and now is cleaner. Then after that tank is done, change the oil.

 

I agree that you can have a carbon problem at this mileage, whether it is the cause I can't be sure. Don't waste your time with the dealer though.

 

Mitchrider, put the Chevron w/ techron in this last week end. Almost have the tank burned off, wil burn the last quarter tonite. Still pings a little, but not as bad. Was surprised that the oil turned darker and smells funny. You said that would happen. what causes this?

 

Some of the carbon that is cleaned out gets in the oil. Have you floored it yet with the cleaner in? That is usually what really cleans it out. Then change the oil after the complete tank is done and fresh gas is in the tank.

 

Yes, it's been floored several times. No noticible black smoke. Thanks for all the good info.