98 Grand Prix GTP Pinging going up hills

[awk409ak]

Hey guys, I really need some help here. Stock GTP (120K miles)runs great around town. You can drive it all day around Denver with no issues. As soon as you start to go up West I-70 just west of Golden, CO it starts to ping badly and then the temp just raises super fast to the point where it overheats. The Chevy dealer can't seem to find anything wrong. Fuel filter and pump relaced, new plug and wires, intake gasket replaced too. I have always run the 91 oct out that they have out. Like I said, runs great around town.

ak

[GTPpower]

How bad is it pinging?

[awk409ak]

Bad enought that it makes to car overheat and loses power within a mile climbing the hill. I see your from Nebraska, so you may know West I-70 going up into the mountains.

ak

[GTPpower]

I haven't been out in that area for quite a while, so I can't say that I remember it off hand.

Have you tried checking your coolant level, etc?

[awk409ak]

Collant is fine. No codes either.

[Slick2500]

Have you done a compression test or leak down test?

[awk409ak]

No. It does not use any oil and does not smoke at all. Runs fine around town, good performance, just cannot climb a hill without pinging and then overheating almost immediately. The dealer has done testing, but don't all what they have tested.

ak

[darkhorizon]

93 octane? Codes?

[Scottydoggs]

i would think the over heating is the cause of the pinging, not the other way around.

[FordMan77]

Maybe try cleaning the MAF and then Seafoam the engine. Could be carbon buildup in the combustion chamber that is causing a ping under heavy load.

Then only other thing that comes to mind would be a weak ICM or coil(s) that is causing a weak spark and is showing itself when the engine load is high. Would explain why around town it's fine.

[awk409ak]

i would think the over heating is the cause of the pinging, not the other way around.

Well, it does not overheat around town at all, it runs normal temp.

[awk409ak]

Maybe try cleaning the MAF and then Seafoam the engine. Could be carbon buildup in the combustion chamber that is causing a ping under heavy load.

Then only other thing that comes to mind would be a weak ICM or coil(s) that is causing a weak spark and is showing itself when the engine load is high. Would explain why around town it's fine.

Fordman,
OK, what is Seafoam?? Wouldn't you thaink the Dealer mechanic would know to try any of this? Then again maybe not!!!! This frustrating, the car I've had sinse new and is a great car. We can get better tan 30 mpg on the hwy, but just cannot go up the the mountains anymore.

ak

[Scottydoggs]

just how hot is it getting? is there anything on the radiator covering it up, paper, dirt clogging the fins, leaves? do the fans come on?

and does the outside temp on the dic work correctly?

seafoam is a cleaner, it clears up carbon form the inside of the engine, valves and heads piston tops. search you tube for a vid, it makes a nice smoke show lol

[awk409ak]

Temp pretty much max. out. Boils over HOT. Temp light comes on and everthing, pretty much stops running. I pull over as soon as I can. The one time had to be towed home. The second it was cooler outside made it to the off ramp and was able to turn around and go down hill which cooled it and of course no pinging then, drove it home. Have not been up to the mountains since. I only brought it up, because my wife was driving it Sat and said it was pinging again. This was just going up a small hill in town. I guess nobody knows!!!!!!!!!!! 91octane, no check engine light, so no codes.

ak

[Bio248]

stop pushing it so hard with the torque converter locked in overdrive.

[Scottydoggs]

ever bleed the coolant system? or change the thermostat?

how about them fans? they ever come on? out side temp reading correct?

[awk409ak]

I used to be able to fly up the mountains. You say I should put it in third gear (3D)???

[sdogg201]

Well I own a GTP and know these things have coils but back in the day when it was distributors and points pinging was from the timing when you was advancing until it pinged then turned back to retard it. How many miles are on your car? Do you get on it at all? have you ever checked the timing chain for stretch or the dampener? Like I said before not sure but pinging to me is a timing issue if your timing is off do to wear it would ping and possibly overheat under heavy load as it is working harder and having a timing issue.

Or could be your pinging cause of timing under heavy load and your overheating do to thermostat not opening all the way up when it's needed under that load. You dont see it in town cause your on level roads for the most part so thermostat does not have to open up all the way and you don't have the hard uphill load on the engine.

[rafadavidc]

I'm with some of the guys in the thread in that there's a cooling issue that heats the engine to the point that you hear the pinging. I don't think the pining is causing the engine to heat up.

- Do a pressurized full-system coolant flush?
- Are the fans running?
- Is the thermostat good?
- What's the status of radiator fins? This is a fifteen-year-old car - those things crumble away to dust after a long time. Test - drag your fingertip (not fingernail) across the fins for an inch or so. Do this on the correct radiator - the one in front is the AC condenser; the engine coolant radiator is behind it.
- How often are you filling your reservoir? (Correct answer for a healthy system is, "Never.")

I'm sure there's stuff I'm not thinking of.

[Scottydoggs]

its pinging because its hot as balls, not pinging around town. only up a large hill and then it gets hot. from what i gather from his posts,

and hes got 120,00 its in the his first post.


its a cooling issue for sure.