axl911

All,

My 92 C2 pings under high rpms. Already put 2 bottles of Techron and running 93 octane, but it didn't help. No broken dist. belt. What else can I check?

How bad are ping? Will this put a hole in my piston?

thanks,
anthony

Ade - C4 91

Hi,

How do you know that its pinging? High RPM (>5000rpm) pinging is usually quite hard to detect by ear. I'm not saying that it isn't, but why are you suspecting that?

In any event I would suggest you dont drive it. Take it to a PO service place and get them to take a look at it. High RPR pinging will destroy pistons really quickly and the expense will make you cry.

If it is pinging, it could be a number of suspects from a broken Dist.belt or failing HT Leads right up to existing engine dammage, so finding the fault by guesswork could cause more dammage. A Bosch Hammer reading the fault codes in the DME computer will may trace your problem.

Good luck.

Ade.

axl911

The sound is a sharp metallic knock/ping when I floor the gas pedal in. Most of the sound occurs at around 4K. At higher revs, the knock/pinc is much less.

Funny, if I am doing 40 in 4th gear, rpm at 2000 and floors the pedal, there is no knocking/pinging. The engine lugs but no pinging.

Any idea? Are the sharp metallic knocking sounds pinging?

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anthony

Ade - C4 91

Hi Anthony,

Sorry but it's really hard to tell without being there. Pinging is quite distinct, it kind of sounds like a hollow clacking sound. If you suspect Pinging then I really wouldn't try to often attempting to replicate the sound - it just jst make the problem worse. I would get it checked.


good luck.

Ade.

mojorizing

Anthony,

Are you saying you have a mixture of techron and 93 octane. I accidently had techron left in my tank one auto-x and I was slightly pinging. Ran that load of gas out and filled up with 91 octane and ran fine.

How did you determine that you have a good Dist. belt? what method?

Do a google search on "predetonation" and you'll get some good sense of what's going on.

Sorry, I can't be of more help...Let us know what you find.

Kevin

mojorizing

Oh yeah, try running your car in your garage at the dark of night,lights out, and looking at the spark plug leads, dist, other HT leads to see if there is leak through on the insulation (to ground, or to other wire) Have you recently washed down the engine? You'll see small electrical storm in your engine bay if the insluation is breaking down. Be sure you take your tie off before you lean over the engine!Ouch!

Kevin

axl911

I pulled the primary dist plug and started the car to check the secondary dist belt.

I did have techron and 93 octane gas.

The pinging is a metallic clacking sound...very distinct.

I will do a complete service on it to see if it helps.

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anthony

SteveW@stig

Take the car along to your local Porsche specialist and have them hook up their tester to the diag socket. They will be able to read the ping count and see what has been happening. You can check the knock sensors yourself if you want with a timing light. With the strobe on *lightly* tap one of the knock sensor with a screwdriver and you should see the timing retard by 6 degrees.

The DME should not let the engine ping so it is most likely the knock sensors.