1993 F150 5.0L - Won't Start, Fuel Pump?
 

Still working with my baby here, but now I think I may have a fuel pump problem on my hands. In 2010, I had the fuel pump replaced and got charged an arm and a leg for it (they had to take the bed off). Fast forward today, two years later, my truck hesitated and cut off on me when I was coming out from a stop light and shifting into second gear. I had to get it towed back to my house.

Talking with the tow truck guy, I learned that there are two fuel pumps on the '93 F150. He suggested that perhaps the side pump was bad. FYI, my battery is new, alternator is new, starter replaced in 2010, and I am pretty familiar with these problems and am certain it is not one of these components.

When I got home I tried to start the truck up, and it actually cranked up with a little hesitation. However as soon as I hit the gas pedal trying to get it inside the garage, it cut off. It will not start up again. Right before I turn the ignition all the way I can hear a noise, sounds like a quick humming, which I am pretty certain is the side fuel pump.

Bottom line is, I am not 100% certain if it is the side pump, not sure if they replaced both pumps back in 2010 or just ripped me off, and I am not certain how to test if it is anything else. I do most of the maintenance on the truck myself omitting engine work and anything I just don't have the tools or help for. From what I understand the side fuel pump is easy to replace (if it is that), but I have never gone about it. I also saw a post somewhere else that it could be the relay, but I think that would have been replaced back in 2010 (or should have). Any advice would be greatly appreciated. Thanks!

The pump in the tank is a low pressure supply pump. The one on the chassis rail is the hi press pump. The best way to confirm proper operation is with a fuel press gauge.
The pumps are energized by the computer through the f/p relay. When you turn the key on you should hear the tank pump run for 2 seconds. If you attempt to start the vehicle it should generate an RPM signal that the computer sees and keeps the relay energized.
Usually the vehicle will run with only the tank pump, but barley. Need hi press pump for regular operation. There are other tests that should be done to rule out a stuck open press regulator. Need that fuel press gauge !

Call me an old cog here, but this body style only had one pump in each tank; the earlier style (about '86 through about '90) used the rail pump. Might want to check this out, as I've seen rail pumps put in to solve some other kind of problems in these, but I'm really sure that stock, it came with just the two.
And lifting the bed is really not hard to do and the easist way to replace these pumps.
Good luck!

My 92 f150 had the pumps in the tank only none on the rail. so I believe you're right Greasemark

Thank you all for the helpful advice. I have been out of town, so was able to escape this problem for a few days. I guess I should start with, does it sound like a fuel pump problem?

I am thinking it has to deal with the fuel system, because it is an issue dealing with ignition and it is not the battery, starter, or alternator. I do have a small cylindrical object attached to the lower rail on the driver's near the rear wheel, and this object has a fuel lines running through it. I was thinking that was the "2nd fuel pump." Is there any chance that that is something else that I am just not aware of?

Either way, what tests can I run to figure out what the problem is exactly?

Thanks!

Exactly ? Fuel pressure gauge !

Hey guys,
I must say that there is a void in my experience background since I maintained a fleet of 67 Econolines assorted 150's 250's and 350's that could make my guesses on F series not totally accurate.The best definition of experience that I can offer is; Experience is what you get when you get what you don't want !

Oh Hanky, it's not like there's THAT much difference between the good old E series and the F series. But don't worry. I'll be sure to point out any mistakes...er...errors you make!

Let's hope I don't keep you too busy !
Beside that, If I was perfect there would be no room for improvement.

Hey Fellas,

Thanks again for all the help, and I still need more! So I my truck, 1993 F150 302 V8 Manual, has one fuel pump that is inside the tank. The device I was looking at on the driver side chassis rail was the fuel filter. I started with that and replaced it... still have the same problem.

Next, I replaced the FPR, which was simple but a pain to reach. However, the truck still will not turn over. What I do know is that after all of this I checked the fuel pressure per the valve on the fuel rail and the pressure is incredibly low... almost non-existent. So the problem is within the fuel system. I went back to double check the work I did, and it all seems right, no leaks, everything on solidly. So what other options am I left with?

Also, does anyone know where the heck the fuel pump shut off switch is? The manual says "R.H. side below instrument panel" but I do not see a dern thing! I figured I would try resetting this, but I can't find it!