1991 Explorer No start

[auburn56]

I was driving on the freeway, when the engine just quit. I tried starting it and it would it would turn over with no problem but no start. After towing it home, i checked the plugs which were in bad shape and replaced them. Tried turning it over again with a couple of the plugs out and observed spark. When i turn the ignition key on, i can here the fuel pump come on for a few seconds as usual. With the plugs back in, the engine turns over and i get an occasional backfire, but thats it. I am suspecting the fuel system but any advice would be appreciated.

Thanks,

Dan

 

[MrShorty]

Best thing to do if you suspect the fuel system is to put a fuel pressure gauge on the fuel rail and measure the fuel pressure.

 

[Critter92X]

If the fuel pressure checks OK it's possible the timing chain/gear is wore out.Although they usually don't jump time untill you shut off the engine I have seen them give out a couple times while it's running. If it's backfiring it almost sounds like a timing issue. If you have good spark and good fuel pressure it might be possible.IMO

 

[savagefan]

A timing light could verify this. Is the spark strong and regular?

 

[auburn56]

Thanks for the replies, I have checked the timing chain and all seems well. When the engine quit there were no mechanical type noises from the engine, it just quit running. From what i can see the plugs were firing as they should. It does not backfire with any regularity. Where on the fuel rail would i put a fuel pressure gauge? And what kind of pressure would i get with just turning on the ignition or cranking the engine?

Thanks for the help,

Dan

 

[Critter92X]

Look right in front of the coilpack down on the intake at the fuel rail (metal line running on top of the motor)there should be a valve that looks like a valve stem on a tire with a cap on it.I think the pressure should be between 35-45psi.

 

[auburn56]

I found the fuel pressure port, but did not have a pressure gage to check the pressure. I did however have someone to crank the engine while i held the schrader valve open and would get a pulse of fuel as the engine turned over. Should i consider that proof of fuel in the system? When i would turn over the engine i would get one small backfire and then nothing for the rest of time it was turning over. Its seems to me that if it was the timing i would be getting a steady round of backfires as the cylinders went lean.

Thanks,

Dan

 

[savagefan]

If spark is strong steady and on time two things you must do is check fuel pressure and engine cylinder compression.

 

[auburn56]

Found the Problem!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Sorry to take so long to get back with an answer. After checking everything i could think of without success, i went back to what i originally thought was the problem which was the timing. I took the front cover off and turned the crankshaft and found that the timing chain and gears were not turning. I removed the cam and crankshaft gear and found that the integral keys on the back of both gears had sheared causing the engine to quit. Replaced the gears and the chain and everything works fine. Thanks to everyone who replied with suggestions!!!

Dan

 

[savagefan]

Thanx, for the record did the engine crank at a different speed after the repair?

 

[auburn56]

The engine cranked at the same speed. Now that i have that fixed, i have a lifter on the right side that will not pump up and so the top of the engine has to come off. At least this time i know what the problem is!!!

Dan

 

[savagefan]

If you haven't taken the engine apart, now is a good time to check your oil pressure, this could be the root cause of the problem. For those keys to shear suggests high resistance to rotation, I've never seen both kick out at once so tread slowly before spending too much. Good luck.