1992 Ford F-150 Fuel Pump/Wiring

Tiny
ADAMMOTTER
  • MEMBER
  • 1992 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 64,000 MILES
So I've had this truck for almost 2 years and for the last year it has been giving me random problem after problem. The latest of which is that it simply won't start or it will only "start" with the accelerator to the ground and it is extremely rough. I've replaced the fuel filter, fuel pressure regulator, spark plug wires, spark plugs, fuel pump relay, router and cap. Recently I removed the wiring harness above the front fuel tank to test it and the truck started without it on but once the accelerator is touched it dies. It also dies if I start it with the wires unattached and attach them while running. I don't know what to even test or try to replace anymore. I've been told it is wiring issues by some and the fuel pump by others.
Monday, August 23rd, 2010 AT 3:51 PM

9 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Has the check engine light come on? Have you checked fuel pump pressure?
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Monday, August 23rd, 2010 AT 10:21 PM
Tiny
ADAMMOTTER
  • MEMBER
  • 4 POSTS
Yes the check engine light is on. And yesterday a friend brought over a fuel pressure tester. We tested both tanks and they both gave off a 40 pressure reading. But once we unplugged the front tank the pressure dropped to nothing and the truck started (from the front tank that is). And we could keep it running as long as we gave it some gas all the while the pressure stayed at 0. But once we switched to the back tank the truck died and the pressure shot right up to 40 again.
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Friday, August 27th, 2010 AT 9:24 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
That is really odd. At 0psi, it shouldn't run. Were you checking the fuel pressure at the fuel rail?
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Saturday, August 28th, 2010 AT 12:36 AM
Tiny
ADAMMOTTER
  • MEMBER
  • 4 POSTS
Yep, directly on the fuel rail. Even had to record it to show my friends boss because he didn't believe us.
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Saturday, August 28th, 2010 AT 11:41 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
I have to say I honestly never saw anything like that. Will it continue to run that way?
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Saturday, August 28th, 2010 AT 10:58 PM
Tiny
ADAMMOTTER
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  • 4 POSTS
It will run but it isn't drivable by any means.
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Tuesday, September 7th, 2010 AT 1:15 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
I have to admit. I'm at a loss. I will forward this to a different tech to see if he has any ideas.
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Wednesday, September 8th, 2010 AT 6:58 AM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the fuel pump check valve on the rear tank

All Technical Service Bulletins
Information

Number Date Title
93S68 09/01/1993 Recall - Cross Tank Fuel Flow Condition

Some of the affected vehicles may experience a cross tank fuel flow condition due to a damaged check valve in the fuel pump/sender assembly. Fuel may be supplied from one tank and some or all of the unused fuel may be returned to the other tank. Should this occur, the capacity of the receiving tank may be exceeded and fuel may overflow from the filler cap. Fuel spillage in the presence of an ignition source could potentially result in a fire.

To correct this condition, the fuel pressure regulator will be replaced and a check valve will be installed between each fuel supply line and fuel tank.
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Wednesday, September 8th, 2010 AT 8:33 AM
Tiny
ADAMMOTTER
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Ill see what I can do, thanks a bunch.
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Wednesday, September 8th, 2010 AT 11:08 PM

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