I have a 93 F150 with the 351(5.8 ltre)in it.I have had this problem since owning the truck a year ago and it's driving me crazy.when I go to start it,95% of the time it cranks for awhile before starting..I have already replaced the starter.since then it just cranks harder..I've noticed that when turn the key to on let the fuel pump prime a bit it will start a little quicker but not like it it's supposed to.It seems like it is not getting the fuel right away..sometimes it starts like it was still sitting on the showroom floor,but not very often..how can I get that new truck starrt again??????

 

Cycle the key from off to on 4 or 5 times within about 10 seconds. Then attempt a start. If she now fires right off, you probably have excessive fuel pressure bleed-down.
The most likely cause is leaking check valves in the tank.

You can diagnose this with a fuel pressure guage. Attach to the Shrader valve. Cycle the key. It should come up to 40PSI. It might take two key off-on cycles to get there. But the real question is how fast it bleeds down. You should lose no more than 5 PSI in 30 seconds.

If the loss is faster than this, you can use a process of elimination to find where it is going. Bring the pressure up. Pinch off the fuel return hose. If the excessive bleed down stops, the regulator is bad. Bring the pressure up, then pinch off the supply hose. If the excessive bleed-down stops, the check valves in the tank are bad. Bring the pressure up, pinch off the regulator vacuum hose. If the bleed down stops, the regulator is bad. If none of these things helps, one or more fuel injectors is leaking.

If there is no noticeable bleed down, it is possible the TFI module or pickup is bad, or the "Push start" feature of the TFI is not working. Check spark strength/quality while cranking.

 

In addition to what fefarms stated, nicely done, make sure that if you are going to replace any component of the system that you bleed the system at the same schraeder valve (looks like a tire stem valve) on the fuel rail. I'd also change my fuel filter just on principle as you're going to be in the system. Out of curiosity,you didn't change the fuel filter without bleeding the system did you. If so you've got air in your system and will have some of the issues you described above.
Tex

 

Hey Lookin, I had a very similar problem and it turned out to be the ECT (Engine Coolant Temp Sensor) that sensor went bad causing the fuel system to keep flooding the system thinking the engine was cold still and it would happen to me usually after I let the truck warmup almost always, if the truck starts up good the first time and the second time it just cranks, give the ect sensor a check. Of course I had a ect temperature sensor code that kept being throw from the computer, do you have any check engine codes at all???

 

wow,I 'm thanking everyone for all the responses.I did'nt expect so many so quickly..I'm going to try it all today..will post my reults..

 

lookin2: I'm anxious to hear the results of the things you tried on your truck because my '92 w/351 has been doing the exact same thing for years now. I tried a few things but nothing seemed to work so I just figured that was the nature of my engine. According to the posts, there may be hope after all.

Question for 'fefarms': I've already confirmed that I'm loosing fuel pressure pretty quickly once the IGN is OFF. I replaced the pressure regulator on a hunch but that didn't work. Are the "check valves in the tank" that you mentioned a part of the fuel pump or are they entirely separate components?

 

[B]Thanks 2 U Lookin2 U may have solved the problem 2 my 4.6 E-150 Van problem which started New Years Eve now exactly is the fuel pressure regulator? In the sending unit of the tank because I replaced the fuel filter & do I put air thru the tire stem part of the schrader valve or do what the senior users do?

 

For the trucks with an in-tank high pressure pump, Ford bundles the high pressure check valve, shuttle valve, high-pressure fuel pump, and strainer into something called a "fuel delivery module". Auto parts stores sell this as a "tank and strainer assembly".

It might be possible to replace just the pump, using aftermarket components, but Ford's intention seems to be to replace everything at once. So I would say they are not "entirely separate components".

 

I had to go to a professional Lookin2 fefarms is right It is the fuel pump because on my E150 4.9 6cyl the valve in the tank is actually a fuel pump inside the tank & if that's working then the external fuel pump is not.........Fuel injected engines have to have 2 pumps ext and int otherwise if it just draws on the one in the tank it won't keeping running and/or start and visa versa....Use ta own a 78 E150 I put a ext electric pump on 6cyl but that was a old fashion carb U can draw fm just the pump fm the tank 2 ta carb.....The one's we have now forget it!!!!
Cost me a arm and a leg!!!!!!!!! Seee Yaaa!!!

 

hey, what's this about bleeding the fuel system after changing a fuel filter? I have some of these symptoms and recently changed my filter. how do you bleed the system? through the schrader? I have driven several hundred miles since then...will it bleed itself out over that time? thanks.

93 f150 302 4x4

 

Did that I opened one and/or both fuel lines 2 see if the pump was working, It started after a few tries but petered out 1/2 mile fm home so I ended up bleeding air out of it again till it started again & got it home, Had my brother drive me to the auto parts store-it started up & I moved it enough to get to the filter, replaced it & it would'nt ignite so on Monday I try 2 start it to take to a mechanic it started & I drove all the way to his place..had him check it and found my external pump was shot..So I'd check the external pump first because mine was only drawing fm the pump inside the tank & w/fuel injection U have 2 hv 2 pump 4 the injector 2 get full pressure....Nuff Said!!