91 F250 5.8 no start

The fuel pump does not shut off after a couple seconds with key on like it's suppose to. It just keeps running constantly and the truck will not start. I am EFI dumb so please explain in plain english if you can help me.

A carburetor and HEI distributor are looking better and better.....

your are out of fuel !
Frank

LOL.....no sir thats not the problem but that is a good one. Both tanks do the same thing and I know there is gas in both.

did you check fuel pressure???? on fuel rail there is schrader valve for checking fuel pressure, if ya dont have a gauge you can push it down with a small screw driver but watch you eyes n dont crank it over or you could cause fire, it should squirt out profusly . if not you have a problem in pumps or switching valve, i think the switching system changes around that year so could be 2 diff. sys.

Frank Merkl wrote:your are out of fuel !
Frank

I like your thinking Frank. If they can't build any pressure then they will just keep running.



Does it smell flooded? Did u pull a plug to make sure you have any spark? I would be the ignition module on the side of the distributor is the problem. That is the most common and where I would start.

Check your Fuel pump relay sounds like it is sticking . Those are bad to stick and flood the engine , also check your oil and make sure it isn't full of gas . pull the red hose off of the preasure regulator and see if their is any fuel in or around it if so then it is bad. If all of this checks out good take some carb cleaner and spay some in the throttle body and see if it starts if it does then the fuel pump is bad or you are out of fuel. And as always check the power supply , all of your fuses and fuel filter.

Those older EEC IV were famous for flooding in the extreme cold. I doubt this is your situation but if it is flooded put the gas to the floor and crank it over just like you would do with a carb. It will start popping and firing as it burns all that excess fuel out of there. At that point you might have to let it sit for an hour or two for that extra fuel to evaporate but at least some firing would be an indicator.