1991 Grand Marquis - 112,000 miles - 5.0 dual exhaust - I was given this car after it overheated on the freeway. After pressure washing the engine compartment, it was obvious that the water pump had failed (literally broken at the heater hose). I replaced the pump but found that the engine ran poorly. Suspecting a head gasket, I took a compression check and found that all cylinders were within specs with the lowest at 115 and the highest at 140. Judging by the way the car turned over and ran when it would finally start, I then suspected that it had jumped time. I have now found after dismanteling that it has not jumped time but that the timing chain is very loose (great deal of play)And the marks are not exactly lined up (very small difference,maybe 1/8" to 1/4"
. Could this be the reason that this car runs the way it does? Or did I miss something? Thanks, I will donate to the cause...
No what I see in the pic is normal chain deflection. If therer are no codes when you say the engine runs poorly, how so? Any backfires, does it stall. Etc. Etc.
When was the last tune up? Try dissconnecting the neg battery cabel for about 20 sec. This will clear the memory, and the computer will re-learn by your driving habits. Where you have the engine in this state, and zooming in on it, why don't you reset the marks any way!
March, 25, 2007 AT 8:45 PM
There are no trouble lights lit up except for the occasional air bag light which was covered earlier here. no check engine light. no backfires. It is hard to start and once it is started, it has to be coaxed to run by revving the engine for a few seconds and then it will finally go to a rough idle. The battery has been disconnected enough times by the the car just sitting and it needing to be recharged. I did drive the car 40 miles from where it was given to me from. I will go ahead and replace the chain and gears and reassemble - the timing marks dont have to be "dead on"?
March, 27, 2007 AT 1:52 PM
Yes! Take the chain off and rotate the crank to match the cam.