I make lots of bad decisions. This one is a 92 f150 XL 4.9 that has been sitting for about 10 years. It wont run. The only code is 542--fuel pump circuit failure. PO replaced the fuel pump. I asked him for the old one and bench tested it and it worked fine. In the process of replacing the fuel pump he cut the metal fuel lines and hose clamped hose to the cut metal. Those will have to be replaced. I have done the usual tests and working my way back. Wish me luck.

 

Gotta love that!!

Shouldn’t be that hard to figure out where it is losing power to the pumps. Good luck.

 

Perhaps the PO crossed the lines when he did the job...….

 

That is certainly possible. Testing the brown/white just behind the cab, I have a power for 2 seconds when switched to on or start. Shouldn't it be constant until pressure is up?

 

If you are talking about the fuel pump running about two seconds that is normal and all it takes to supply fuel. Sandy

 

She is a beaut. almost an identical sibling to my 93.

 

If it is still on the trailer you can bring it to my house and pretend you never made a mistake at all! I am used to trucks with occasional troubles, it goes with the territory.

 

Crap, half-assed repairs. #1 with a bullet reason these things end up in a yard.

Front yard, then junk yard.

Congrats on the save.

 

Dumb question, but what are you going to do about the snipped fuel lines? As far as I know, they're not available....I could be mistaken, though.

 

OK, but what is the bad decision here?

 

Not having it off the trailer and in the shop. Oh, and starting to work on it!!!!!

 

I'm planning on nylon for the pump to filter. Not sure where that return goes...

 

I know pictures are worth a thousand words. It's been off the trailer but I dont take a bunch of pictures. Anyway, now I have done all the checks that I know of. I have just a moment of power to the pump then, nothing. Pulled the pump and tested it on the bench and it works. Does anybody know what direction I should go next?
Bad decision= I bought this truck from somebody that needed the money due to health issues. I paid a lot more than what a non running truck is worth. Maybe I should change the name of this thread to "Charity Case"
Everybody in the family likes the truck. They just wish it was running. If I can solve this no fuel issue, I'll tackle all the small issues so that the truck is reliable for my wife to drive. Brake master cylinder leaking, fuel lines, broken spark plug wire, missing battery hold down, broken windshield...

 

I am not up on the newer trucks (80-86) but on them with electric in tank pumps when you turn the key to on the pump will run for about 2 seconds, like you get so that is good and shows the wiring to pump should be good.
Now IIRC they use a fuel pump relay and they can go bad, think it is under the hood.

Some go thru a oil psi switch that will turn the pump off if the motor is not running. How many wires go to your oil psi switch?
Now if the switch is no good then no power to the pump(s) but you can jump the switch out for testing just make sure you get the right wires.

Then there is a crash switch. If the truck is in an accident it opens to stop power going to the pump(s) even if the motor is still running and drive could not turn the motor off.
In the 80-86 this switch is behind the glove box, don't know where it would be on yours even if it has one.

Hope this helps even if not for your year truck but cant see them changing much between years.
Dave ----