Marquis pinging on uphill climbs - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

rreitz · 09-29-2007, 18:39

Hi - first time posting. Nice forum. I have a 1994 Grand Marquis )4.6L) with 170000 miles on it. Lately, its starting to ping when under load going up hill. It also uses about 1 quart of oil every 500-700 miles. Other than that it runs fine. Any suggestions on where to begin with the pinging problem? I would like to get at least 30000 more miles out of it but I think the pinging may be damaging the engine. In the old days, I would just retard the distributor a little but can't do that on this car. Thanks for any suggestions on where to start.

Kleetus · 10-07-2007, 09:45

Have you changed the plugs in it? If you're burning that much oil, I'd be someone put hotter plugs in it to keep it from fouling them out. That will increase your ping a bit. Have you tried running 89 in it instead of 87? Could also be the different fuel formulation depending on what time of year you ran into this.

Freshmeat · 10-09-2007, 11:40

At 170k, I'm willing to bet it has A LOT of carbon build-up, which will easily increase compression to the point it's pinging.
Go get a can of Seafoam from the local parts store.
Let engine get up to temp.
Turn off engine.
Remove the fat vacuum line where it connects to your brake booster.
Start the engine.
Slowly pour the Seafoam into the brake booster vacuum hose. If it dies, just crank it back up.
It's gonna smoke like nobody's business.
Use up the whole can.

Drive around a bit and see if you notice a difference, particularly in the uphill climbs.

One thing you can do to avoid carbon buildup is to really put your foot into the throttle once in a while. Running at high RPM (4,000+) ONCE IN A WHILE helps clean out the combustion chambers and actually helps the engine run better.

rbohm · 10-09-2007, 20:03

in addition to what freshmeat said, i would also run a few tankfuls with a can of seafoam in each tank. this will aid in cleaning out the injectors as well.

as far as the oil consumption problem, start by looking for leaks, and have the valve seals checked.