2000 f 150 5.4, cranks but wont start, very intermittentchanged pump relay, pats system doesnt continuously flash while its cranking, then all of a sudden it will start, i can hear the fuel pump come on for the most part , any advice welcome thanks

 

If you replaced the fuel pump: Is it the right one?

If you didn't: Check your fuel filter...

Although it can be many, many, manny different things (the list goes on, and on...) the above two are somewhat common....

 

My truck is doing the same. If you find out anything let me now. I have tried several things as well. NO luck

 

no havnt replaced pump yet, going to check fuel presure in the morning

 

After hours of online research here is a few things I have tried from the experts. This will start the narrowing process.
*Lightly press gas pedal while cranking (no more than 4 seconds of cranking). If truck starts IAC issues. Clean or replace. Located behind throttle body slightly left near firewall. Two 8mm bolts one connector.
*Press pedal all the way. If truck starts faulty injector, causing fuel pressure to drop.
*Look at dash THEFT light while cranking. If it flashes PATS system issues.
*Remove line off fuel regulator. If you smell gas, bad diaphragm.
*Clean MAF. Located inside large air filter tube going to throttle body. Clean with nonresidue cleaner or MAF cleaner. I used carb cleaner.
*Check fuel pressure at the rail. Located passenger side rail schrader valve. 35-45psi. See if pressure holds after pump is off. If pressure drops could be a bad injector leaking down or regulator diaphragm.
*Check PCM #2 Relay under dash. Listen for click. Check PCM relay under hood #304. Check fuel pump relay under hood #301.Check PCM diode under hood #501. Check the inertia switch (fuel shut off switch) under passanger side dash kick panel. Has a reset button on top.
I have tried all of this on my truck and I am still stuck. Sometimes it starts sometimes it doesnt. Anyone please help.

 

checked all relays, checked fuel presure took 5 on offs with key switch to pump up over 30 psi, held presure for over 10 minutes with out bleeding off, pump presure while running was only 26 to 28 psi, im leaning toward a bad pump,for the most part it would also just pump straight up to 35 psi with first turn of the switch, i say the motor itself is getting bad, any comment ? thanks

 

I'd say your diagnosis sounds correct......

 

yup sounds like its time for a new pump to me

 

Just read online that the dbpe sensor will disable the pcm. I checked mine and it was clogged bad. Have one on order. Noticed vac line was cracked.

 

yea had the same problem but wasnt causing a start up issue at all, but you should be getting a check engine light on with that being bad

 

After days of staying with my truck I got it. Noticed a small drop of anti freeze near the cross over. Thought it was the gaskets. Turns out the intake manifold cracked at the thermo housing. Bought a new intake and installed.

 

Double check the rear coolant block port on the passenger side, if you used after market gaskets sometimes they wont hold and you will have a small coolant leak next to cylinder 4, ford updated their gaskets just for this side to a thicker one for this problem and felpro makes a problem solver gasket kit for this which is extra thick. If you used oem ,no worries

 

I did buy the dorman am intake. Got it home and the generic signs started showing. There was not any nut inserts for all of the controls and components. So I went with Motorcraft from dealer and oem gaskets. There is definietly a difference. Go original or go to junkyard. They actually wanted you to use a course hex screw to hold throttle cable power pump bracket and others. It did get returned. Wanted to thank all who posted forums on this site and others for their info and past experience.