Carbon Deposits and Pinging

[Smokie]

I have ocasionally noticed (heard) light pinging under very light throttle conditions from either dead stop or near stop. Here are the conditions under which this occurs 100% of the time

1. Engine rpms always below 2000.
2. Outside Temp. display reading 98 degrees or above.
3. It never occurs under medium to WOT.

I have the base tuning and pulley that comes with Trilogy kit, no engine mods other than the contents of T-Kit. My kit has 10,000 miles the car has 37,000 miles. No, I don't have bad gas.

I suspect that carbon deposits in the combustion chamber may be the culprit and I am considering using a combustion chamber cleaner.

I would appreciate comments and suggestions, both on the "cause" and also on possible "cure". As always...Thanks.

[Bobby Clobber]

Smokie,


Are you sure the pinging is not some ricemobile rattling around in your pipes?:burnout: :beer:

[nomad]

Get a dyno. Check your A/F ratio. BIG peace of mind.:)

[Smokie]

Smokie,


Are you sure the pinging is not some ricemobile rattling around in your pipes?:burnout: :beer:

Something my car inhaled?:D

[Smokie]

Get a dyno. Check your A/F ratio. BIG peace of mind.:)

You mean like a diagnostic thing??? It wont do it at WOT, you mean check below 2000 rpms at very light throttle???

[SergntMac]

Javier, look into an off-the-shelf product called SeaFoam. I used it on my #3 car when I first got it. 1 pint per tankful for 4 fillups, then 1 pint every 4 fillups. It works. Throttle response and MPG improved over testing. Cleans the entire fuel and combustion systems, no harm to cats or 02 sensors.

[Zack]

Oh jesus people, its in the timing tables.
Along with the timing values based on intake air temperature.
I little tweaking in the tune and it'll be gone.

[nomad]

You mean like a diagnostic thing??? It wont do it at WOT, you mean check below 2000 rpms at very light throttle???
Yup!
You have a generic "safe tune" from Lidio.
Absolutely nothing wrong with that! Only problem is, it's a generic/ get you going tune/. Your car, and your driving have both changed since you installed your s/c.
Javier, I am not a mechanic. However, I do know that pinging at ANY speed is not good!
Unless somebody can dispute me, I would recommend a dyno tune to diagnose why your car is pinging.
Sounds like you need a minor "tweak".
Just be careful in the meantime.
No hard acceleration in exteme heat.:nono:
P.S. Is it possible you only hear it at low rpm's because at higher rpm's the sound of your car drowns it out? JMHO

[Smokie]

Oh jesus people, its in the timing tables.
Along with the timing values based on intake air temperature.
I little tweaking in the tune and it'll be gone.

I agree that decreasing timing advance will without any doubt make the problem go away, the reason I wanted to explore carbon deposits as a possible cause is because I got the blower May 2005 so it already went thru one complete Florida summer without any pinging.

I don't mess with my tune, don't know how, lack the equipment. The reason I thought of carbon deposits as a possible culprit is because I remember some pictures Sarge put up during his rebuild and there seem to be considerable amount of carbon build-up on the pistons.

Temperature is a factor without any doubt, timing advance at light throttle is also a factor...why a year later remains an unanswered question.

[Smokie]

I have ocasionally noticed (heard) light pinging under very light throttle conditions from either dead stop or near stop. Here are the conditions under which this occurs 100% of the time

1. Engine rpms always below 2000.
2. Outside Temp. display reading 98 degrees or above.
3. It never occurs under medium to WOT.

I have the base tuning and pulley that comes with Trilogy kit, no engine mods other than the contents of T-Kit. My kit has 10,000 miles the car has 37,000 miles. No, I don't have bad gas.

I suspect that carbon deposits in the combustion chamber may be the culprit and I am considering using a combustion chamber cleaner.

I would appreciate comments and suggestions, both on the "cause" and also on possible "cure". As always...Thanks.

Above is how this thread started and it did not recieved much response which may be due to not many people having this problem.... and that is a good thing.

Since then I proceeded to run a bottle of the Chevron additive called Techron. Finished that tankful and I am about 290 miles in to the first tankful after using the product. My reason for suspecting that the pinging may be carbon deposit related is because I have the same tune I had all last summer without any pinging.

The outside temp. display today reached 105 degrees, I spent 20 minutes idling at the bank's drive-in teller and then I got caught in bumper to bumper traffic for about 30 minutes, this scenario would be certain to generate the pinging my car had back in June.

I actually went out of my way to duplicate the driving that I thought would be most likely to generate pinging and there was none. I realize that this is not proof positive that my theory about carbon deposits being the culprit is correct, but at least it is probable that in my case it was correct.

Even if this thread generates no further interest or desire for discussion, it is part of the record and a search on "pinging" should bring it up. At this point I am satisfied and happy because I really was not looking forward to "detuning" my car...of course if the pinging should return..I'll let you all know.

[Hotrauder]

Javier, this is good 411 for all of us to heed as we put more miles on our babies. We know that Techron is a quality product that works and without any down side that we know. Good insurance to add some on a regular basis even with no known symptoms of preignition. Particularily here in high heat situations. Interesting that your pinging only at low rpms. Good catch to find it as we normally don't worry in the loaf along range. Thanks for the heads up. dennis

[sailsmen]

After some bad gas, ( very common up to 5 months after Katrina ) the car was not running right. I put in some Lucas fuel treatment and it cured the problem.

Apparently some of these additives will work for some problems.

[JACook]

Since then I proceeded to run a bottle of the Chevron additive called Techron.
Yes, good 411, this. I've always been a fan of Techron, so much so, that Chevron is the ONLY gasoline
I put in my cars. I still do a bit of mechanical work on the side, and Techron is one of the tools in my kit.

I know there are those who will say all gasoline is the same, and it comes from the same place, blah, blah,
whatever... This is a half-truth at best. Fact is, it doesn't even pass the sniff test. While it may be true
that the gasoline itself is the same, what we buy out of the pump is a bit of a witches brew of gasoline,
plus lots of addititves. And it's the additives that can help or hurt.

Hand to God, I used to have a problem with my carbureted '85 GT when the weather was cold, and if I
used Mobil gasoline. Always liked Mobil till then, but they changed the formula, and both myself and my
neighbor (who's also a mechanic) had problems with sticking carb float valves. Stopped using Mobil, problem
gone. All gasoline is the same? :bs:

Some of the addititives can cause vacuum system hoses to turn to goo. Others just gum up fuel systems.
It's a pay-me-now-or-pay-me-later proposition. I tend to keep cars for a long time, so for me, the ~6%
price differential isn't worth taking a chance on the cheap stuff.

[Zack]

This is just a testament that these engines have to be beat to run properly.

[Smokie]

This is just a testament that these engines have to be beat to run properly.

I completely agree, when I'm a the track I beat on it like a dog. But most of the miles for the past 12 months have been on weekends only; a lot of extended low speed driving, lots of idling and short trips.

I'm at 38k miles and I suspect the "driving Miss Daisy" style of driving created a problem where more agressive driving for longer duration would have prevented the problem.

[Marauderjack]

Don't forget that the "Adaptive Learning" aspect of our EEC's will try to squeeze every ounce of fuel economy and I suspect that driving like "Miss Daisey" will cause it to lean out and advance the timing to the point of light pinging at light throttle.....This won't hurt a thing but it is annoying!!:argue:

Changing the timing tables may fix it but the EEC may over ride them if you "Baby" it too much.....Soooooo Let 'Er Rip!!!:burnout:

Another note.....I feel like we are not getting 93 octane all the time as "Enterprising" merchants are probably making additional profit by diluting the 93 with 87 or 89??:confused: The test for this can be pinging in your car!!:mad:

Good Luck!

Marauderjack:bandit:

[O's Fan Rich]

This is why I added the Snow Meth kit to my car.
I've also been told that it'll help keep the internals cleaner.
$400.00 well spent IMHO.

[DEFYANT]

How about a borescope to take a peak inside the cylinder?

Engines are like Bear brakes: Every once in awhile you need to really get on it! :D

[MENINBLK]

Disconnect the battery overnight.
Connect the battery in the morning.

TURN OF ALL ACCESSORIES.
Start up the engine and let it run until the cooling fan turns on once.
Take it out onto the Florida turnpike, and cruise at 80 for about an hour.

If that doesn't burn out anything, nothing will...

[Smokie]

I just went thru my 1/4 mile time slips and counted 78 so the beast has been flogged, the problem is, in between floggings too much slow driving...:geezer: