Engine pinging

[Mizac]

Ive got a 94 MGM that pings quite a bit, mostly under load. I run 87 octane fuel in it. It does better with 93, but i cant afford to do that all the time. Ive cleaned out the EGR channel, and the MAF but it still pings. Any thoughts? Thanks for any help.

[Cougo]

I had this problem with my last car (not a Ford product) and it turned out that I was getting carbon build-up in the combustion chambers which cause the compression to go too high and also I suspect, cause hot spots that can cause pre-ignition. The carbon I think was from oil leaking past the valve seals and burning and leaving deposits.
Anyway, the way to check this is to do a compression check. My results were WAY out of spec. so I ran some " GM Top Engine Cleaner through the engine via a vacuum line and it was completely cured, that is until the carbon formed again about every year or so and I just repeated the engine cleaner. If I wasn't so lazy I would have replaced the valve seals and maybe the guides too.
Does your car smoke or use lots of oil?
But first I would check the function of the EGR. I see you cleaned it but make sure that it is actually functioning because a non-op EGR will cause ping.
Other than that there is timing, but I don't know if that is adjustable or not on your model.-BA

[Mizac]

Yes im pretty sure my valve seals are toast. I have the blue cloud after sitting for a moment in traffic and the like. How would i go about checking the EGR? Thanks.

Oh yeah it does burn oil. Usually a couple quarts between changes.

[Cougo]

If you disconnect the vac. line to the egr and suck on it with the engine at idle it should make it idle very rough or even die. If it doesn't then your egr is not working. This is how the smog test guys do it only they use a little hand held vac-pump.
I would definatley get this fixed, as you know a chronic knock can cause big problems, and you may not even hear some of the ping that is going on.
There are products out there for blowing out the carbon and some home-made formulas too. I just know of the G.M.one though, which they stopped selling in Calif. -BA

[Mizac]

Thanks for the info, i will give it a whirl.

[gadget73]

The EGR passages are known to clog on these. Usually it sets a check engine light, and you'll come up with a code for insufficient EGR flow or something along those lines.

[sly]

the egr passages are known to clog on these. Usually it sets a check engine light, and you'll come up with a code for insufficient egr flow or something along those lines.

+1

how to thread (pictures are dead): http://www.grandmarq.net/vb/showthre...ure-with-Video

btdt.

before and after pics attached

and if that's what you mean by EGR channel... then you're probably suffering from valve seal leaks AND worn out timing chain tensioners. You may even need a new timing set. My 93 did that for about 60K miles before the engine bit it.

[Mizac]

I dont have any CEL's coming up. I do know my valve seals are most likely toast, and I have already cleaned the EGR channels. So its possible the gunked up combustion chambers from the leaky seals could be causing the pinging? Would running something like seafoam through it help? Guess its time to change valve seals.

[sly]

be careful about changing the valve seals... if there's any play in the valves, cyl 1/8 could catch a lip and bend an intake valve like my 93 did (cyl 1). running high octane for a while will reduce the carbon as well and the pinging... injector cleaner helps a little too. seafoaming it will also help. but since the valve seal leaking is probably the cause... I'd just run it until the heads can be rebuilt or a new(er)/rebuilt engine swapped in.

[FordMan77]

Run some Seafoam through it and see what you get. Worked good on my 95 bird when it started pinging a bit.