Hi I am helping a friend of mine out with his F150 and he has the inline 6. Basically he goes out for a drive and parks it for an hour or so and it takes many cranks to get it to start again.
I think the fuel pressure isn't holding either with the fuel pump check valve or in the FPR. I pulled the vacuum line off the back of the FPR to see if the diaphram was leaking and it was dry.
Is there anyway to test it to find out which one is faulty or could it be anything else?

 

my fuel pressure reg was bad in my 88 and it dun that. how did u check the diofram without taking it out its under the plentem. i always took em off and turned upsidedown to see if any fuel come out the vacum side be sure to bleed ur sherater valve behind the plentem by the firewall first

 

It's possible you have leaky injectors and it's flooded. If this is the case, it will start if you floor the gas pedal.

 

u could see n smell a leeky injector when its running

 

Thanks guys.

No I didn't remove the FPR and do that. I should have. It looks like 2 allens screws to get it off. Can I remove it and get it out without removing any part of the intake?

I will do try that.

This truck only has 1 fuel pump in the tank and it does have a built in check valve?

How can I verify it isn't the fuel pumps check valve or how can I test to make sure it is or isn't the fuel pumps check valve leaking the pressure down?

Thanks Again.

 

the fpr has 3 allen screw i used a flex drive to get them out

 

Don't remove the FPR - if it was leaking, you'd have seen it squirting out the vacuum port within 30 sec with the engine running.

Yes, there are several valves in the FDMs in the tanks. Read these captions:



Take a fuel pressure reading when it WON'T start, and check for spark.

 

Sorry to revive a dead post but...I am having the same problem now!
When I finally get it started after about 4-5 sec of cranking I can smell fuel...any thoughts?

 

Leaky injectors - it's flooded.

 

but how would I fix that?
Just swap the injectors?
BTW, when it is cold out side (under 60) it never happens...Does happen less now that I have the goodyear belt on.

 

Throw a bottle of Techron in the gas and see if that helps. If the injectors are just dirty, that might clean them.

BTW, hard starting CAN be caused by a bad MAP sensor.

 

Does it run rough? With it idling, pull the Red vacuum line off the FPR and see if gas squirts out of the FPR within 30sec.

 

I ran a whole can of seafoam in the tank not two full tanks ago so I am hoping that cleaned them up some. I noticed if I turn the key to start and let the fuel pump prime, (which I can here it in the cab, is that normal?) then it is hard to start. But if I just get in and crank it with no pause then it fires right up...I am lost. I am going to swap the spark plugs, wires, and mabey the cap and rotor and see if that does anything. But I am also running seafoam in the oil in about 150 miles or so.

 

Also it doesn't run rough at all, very smooth. Mabey a little rough in the morning if I dont park it in the garage at night and it go below 40 that night it runs a little rough for about 30 sec or so then it smooths out...

 

Keep that Seafoam OUT of the fuel tank and ESPECIALLY the crankcase........

Your injectors are shooting fuel when they shouldn't be. They are either leaking or whatever is controlling them isn't working right.