"Pinging"

[kidturbofan]

I have Stage I with Mopar BOV and Airaid CAI. Just noticed a little "pinging come from the motor under high loads at anything above about 80% of WOT.

I think I just started noticing because the weather is cooling off and I'm doing more driving with the windows open as opposed to having the A/C on.

It's my understanding that this "pinging" indicated the onset of pre-ignition or detonation. Is that you guys(gals)take on it also? If I stay in the throttle and let it do this is there a significant risk of damage? BTW, I don't think it's a bad tank of lower-octane gas, I always use premium and gas up at a variety of different stations and the problem seems to be consistent no matter where I got gas.

[:I]

[TripleJackInGA]

Do you live in an area which requires the use of special gasoline additives during winter months? This usually slightly lowers Octane in fuel as I understand it and possibly could be the cause. Beyond that, it is *possible* that you could have a vacuum leak in the intake area somewhere that could make the car ping.This used to happen on Dakota R/Ts because the belly-pan gasket would leak, which would suck air into the intake, and the computer would try and compensate by dumping fuel into the engine since the leak added a lot more volume of air.Have you noticed the fuel usage going up at the same time or any black smoke out the back at WOT ?

[crazyjoe]

Ditch the platinum plugs.

Though every auto parts store I have ever been to has tried to sell them to me, the fact is that platinum plugs are not recommended for turbo applications.

Platinum plugs burn hot, thus helping to keep themselves clean and free of the contaminants that would normally require you to change them at 15,000 miles or so, but those hot burning plugs also increase the chance of detonation/pre-ignition.

HTH.

[TripleJackInGA]

I didn't catch that, but he's right.The hotter the plug, the more chance of pinging.

[Herschel]

KidTurboFan. Check out post "high rpm miss gone."
Champion Plug part number. H.

[crazyjoe]

Sorry...

Normally, platinum plugs are of the 100,000 mile variety....you know, they tell you you don't need changing very often at all. This is because the platinum element burns hotter than a typical copper element, and it sort of works like the self-cleaning oven. It literally cooks contaminants off of it that would normally build up on a copper plug.

Because it retains more heat and gets hotter, it is a contribuintg factor in preignition and detnation.

This is more of an issue on ignitions that use a "waste spark" system (one coil for two cylinders) and I am not sure how the PT GT is set up, but plugs are cheap, check them and see what you come up with.

[3BarBoost]

The platinum plugs aren't turbo-friendly. Best is the stock plug.

On the other hand, the knock sensor usually catches knock long before you can hear it. If you aren't familiar with what knock sounds like, you might be hearing something else. Lemme know how putting the original plugs back in works out.

[kidturbofan]

Thanks for all the replies. I live near Atlanta, and don't think they use a winter fuel additive here. Also, no black exhaust smoke or recent fuel consumption increase. Saw a slight fuel economy decrease a few weeks ago, but think that's due to the Stage 1 computer fuel schedules and higher flow injectors.

Thanks for the info on the platinum plugs, I'll try changing them back!

[MX-5]

quote:Originally posted by 3BarBoost

The platinum plugs aren't turbo-friendly. Best is the stock plug.

On the other hand, the knock sensor usually catches knock long before you can hear it.

The PT knock sensor is not read any time the throttle is over 80%. At that point, the PCM goes open loop and follows the preprogrammed fuel/ignition strategy.

If you hear pinging, you are already 5 degrees too far advanced on the timing. Damage is being done before you ever hear it.

[RossCoe]

MX-5 and 3BarBoost on the same page - what a treat!! So - what if one
were to use store bought 110 octane - would the sensor pick it up or is it outside the programming? Many years ago the trick was to use 115/145 AvGas and pray it wouldn't blow-up.