It started with an internal head leakage problem a year ago.
The work done by a repair shop, and this is the 1st
time anyone but me has ever worked on the car. The head
gaskets were replaced and fixed the leaking problem but I
started getting the pinging. I went down the normal path of
timing etc and ended up replacing all the electronics in the
EGR Engine Gas Re circulation System which is where the
troubleshooting takes you. It has been a very in-depth
problem. I've had the car apart twice and can't seem to find
the issue.

The heads were milled 0.004", however, the electronic timing
advance moves 20 degrees for timing compensation so even if
the timing was off 10 degrees the electronics would try to
correct it. I have put in everything for fuel up to jet fuel
trying to get rid of it and it won't go away.

So it's not something that is a simple problem or just a
timing issue.

I drove the car for about six months
trying to work my way through the problem and there was a
lot of hammering that took place on top of the pistons. On
the road to Mossville on route 6 it would hammer every day
for about two miles.

There is something in there temperature related and that is
where the EGR system said it should be, but to no avail. I
have replaced all three of the electronic components in the
EGR system.

My next step is to tear out all the attachments and remark
the damper at TDC so there's no question about correct timing.
Cleaned and checked all the vacuum lines.
Timing chain has never been replaced.
Problem started as soon as I drove it after the head gaskets were replaced.
Never had a problem up to that point.
I been down the different types of gas road. no avail.
I have checked the vacuum lines for cleanliness.
A common problem in this type of issue is in the EGR vacuum line.
Spent a lot of time asking questions and trying each suggestion with the
electronics guy at Dennison. He knows his systems very well. (A fifteen year
mechanic).

I am posting this for a friend with an 89 - Dave

 

Have you checked for exhaust leaks?

 

0.004" isn't much at all, unless they used thinner head gaskets as well, but even so most engines that I have heard about run better with a tighter quench. Anyway, you seem to have covered that route by using higher octane gas. Does your engine use oil or smoke on start up? If your engine uses oil, this usually causes engines to ping badly. Do you have bad valve stem oil seals? The only other things I can think of is the balancer slipping, which you are maybe going to look into or a badly worn/incompatible distributor gear.(you must use a melonised gear on roller cam engines, otherwise the billet cam will eat a 'normal' cast iron gear) You have obviously ruled out the knock sensor and module if you have followed out diagnosis. I understand these can be upgraded to later parts to reduce knock count retard. This is all I can think of at the moment, but if I get a brainwave I'll let you know. :steering:

 

I don't understand "the timing moves 20 deg so even if I change it the electronics will correct it". Are you setting base timing with the tan/blk timing wire disconnected? Have you tried running with a diagnostic software such as diacom? Does it ping under light throttle, full throttle or all the time?
I believe 6 deg btdc is correct for your car. I had a problem a few years ago with detonation and it was carbon build up on the piston tops and valves from too large injectors.
John

 

Just about to come back and suggest the black/tan ESC connector but John 89 has suggested it. Have you checked the distributor internally for any damage, as John89 picked up the amount of retard is excessive. Are you sure you are timing number one cylinder and not number two ? Just a thought. Other than that, is the firing order correct-has anybody switched plug leads around ? :)

 

Hey - no one has guessed what I think it is - but I forgot to say that the engine has 180k miles on it - except for the head gaskets and fuel pump.

Pinging in a high mileage engine... hmmm :banghead:

I forwarded all of your thoughts to Bill Gardner. He wasn't impressed with my guess. :lurk: