I'm stuck on the same thing.... possibly too much advance, or the timing isn't being pulled when it starts detonating.

Timing not being pulled leads me to think it could be the ESC.

Retard it 2 degrees and see if it makes any difference......

Jared

 

The ESC has been tested. That's not the problem. Good thought, though.

 

We did retard the timing 2* from where it was which was 4*. It made it worse. Then I put it at 6* which should be stock and it was still bad and moved it 2* more advanced and seemed a bit better. (scratching head...WTF) If the balancer had slipped, it wouldn't effect the timing if it was set correctly the first time unless someone else has set it after it "may have slipped" before us touching it. I did think it was odd that it was off 2* from stock when we first looked at it.

The real issue on trying to fix this is that Fred was running out of time and on vacation. If we would have had several days to tear things apart and do a complete job of troubleshooting vs. being on a time crunch, I feel confident that we have found the issue. Popping #1 and looking at the balancer will tell you if it indeed has slipped or not. If nothing else, Fred should have a better idea on what needs to be done in the future to troubleshoot this. Please post up Fred when you find the issue, I'm waiting to hear what it was/is.

 

Search knock sensor on this forum.Good Luck!

 

Hey Fred any updates? Also did Tom take you for a skid in the buccaneer-mobile?

 

Bit of an update. I thought the new plugs made a big difference, but the pinking came back. Weirdly - and this may be my imagination - it seems worse when the tank is under half full.
On Tom's advice, I put three bottles on Techron fuel cleaner in the tank, but no real improvement.
But then today, I fueled up at Shell and they have 93 gas...a full tank of that went in, no additive, and almot no pinking at all.
So - compression too high? Potenitally still carbon making the compression too high??

 

Hello Fred,

I believe the carbon idea is likely but the discussion towards the EGR has me thinking they might have something there. Your car is exhibiting signs of a bad EGR and that should be tested when you get a chance.

The point about your EGR is a very good one and a very real possibility. Can you verify its operation with a vacuum pump while the engine is idling? If the EGR was not working then your car would knock for sure. The EGR failed on my car and my NOX in my emission test was way higher than the limit. The NOX numbers indicated a high combustion temperatures without the air being injected by a "Functional EGR". On my 1988 C4 I never had any lights or codes indicating the EGR had failed. I only learned of it after the emission test indicated a faulty EGR.

If you have to change it you will be down a day or two as it is not the easiest job. Start gathering the parts ahead of time and save some money...

If you haven't tried the B&G 44K yet you might want to try it. I would still run 1 can (only) through your engine on the highway if possible as that would clean out the system and hopefully break the carbon loose if it is there. Too much of a good thing can hurt you sometimes, 3 cans in 20 gallons???

I don't think your Balancer ring has slipped.

Your indicators with the pinging indicate either a bad knock sensor or a faulty EGR. It could be carbon but you should had that blown out days ago. I am going to suggest it might be the EGR that has plagued you all along. That would explain the pinging from day one as the engine is running higher than normal cylinder temperatures and making it ping.

The last guy tried fixing it by removing 2* of timing. It all points to a bad EGR. If you have the knock sensor I would replace it but you can test it easily to know if it is working. While idling take something metal like a wrench and tap the side of your engine, if working the idle will drop momentarily.

On the EGR system be sure that the EGR vacuum solenoid is connected and has a good source of vacuum. Do a good visual inspection of the EGR system. Eliminate the simple things first!

Good Luck and I will be watching for your response!

Best regards,
Chris

P.S. The temperature of my engine never got above normal even thought the combustion chamber temperatures were way high.