I have a '99 Expedition with a 5.4 that has a bout 106,000 miles on it. A few weeks back I went out to start it and it would crank but not fire. I drove my other vehicle to work and that night when I went to check out the Expedition it started right up. Last week it did it again and now will not start unless I give it a shot of starting fluid. When I start it with starting fluid, it starts right up and runs with no driveability issues.

When this first started I suspected fuel pump or relay but the relay checks good and the fact that it runs after I start with starting fluid makes me hope that it is something easier to fix and I can avoid dropping the tank. I replaced the fuel filter but I don't have a fuel pressure test gauge. Is this a symtom of possibly the fuel pressure regulator?

One other thing, I can remove the relay and run the pump through an ampmeter. It pulled about 7.4 amps which I thought may be a little high indicating that the pump is weak, but it does run good once started.

Any thoughts?

 

Sounds like either the fuel pressure regulator is bad allowing all of the gas to drain back into the tank from the rails or the check valve in the pump is bad.
If you turn the key to on for a few seconds then off. repeating 5 or 10 times will it start then? You really need to check the fuel pressure with a gauge. If it drops off real fast when you turn the engine off, I would suspect the regulator is bad.

 

Thanks for the reply. When it does it again I will cycle the key on and off like you suggested unless I go ahead and replace the pump first.

I started it yesterday with starting fluid and it started with no problem this morning before work and after work as well. I suspect you are right about the check valve in the pump. I think at this point it would be better to replace it in my garage or driveway than have it quit me altogether somewhere so I may be ordering a pump tonight.