diagnose a bad 90 F150 fuel pump

Hurley

Hurley

WTFab
Joined
Feb 22, 2008
Location
Statesville
Read my following diagnosis and see what you think-

- single tank model, so no selector valve. No pump prime upon turning key. Inertia switch isnt tripped. 4.9 I6
- Key on, engine off. Checked voltage @ pump power wire going into tank and read 6.6x V
- I ground EEC Test pin #6, forcing fuel pump relay on (so it's good), read full 12V @ pump power wire @ tank. No pump function.


Before I go and spend $100+ and woefully drop the tank, is it safe to say the fuel pump is dead?
 
Yep. If it's got juice going in and you got no juice coming out it's dead.
 
Roger that -

Looks like I can get a replacement pump assembly for $58 shown in the pic:

getimage.php


http://www.rockauto.com/catalog/moreinfo.php?pk=3097308



Would I be going wrong to do this, costing less than half of replacing the entire sending unit assembly... or is it a royal PITA and i should spare myself by buying the more expensive complete unit?
 
Only one pump in 1990.

You just have to attach the pump to the bracket/tank cover plate. Might want to drop the tank and pull the pump out to make sure everything's in good shape. The "complete" pump would come with a new o-ring and stuff. I had one quit because the electrical connections inside the tank came loose, too.

Oh, and make sure to replace the sender float while you've got it apart. Or at least have one on-hand. Replace it if the original has fuel in it. I've had more trouble with those than anything else. They're only a couple bucks at the dealership.
 
I have a 1990 F150 with the 300 in it. I have been through three fuel pumps in it. Everytime they went out I could beat on the bottom of the fuel tank and get it to run long enough to get it home. You might try that just to confirm it is the pump.
 
Shawn said:
Only one pump in 1990.

You just have to attach the pump to the bracket/tank cover plate. Might want to drop the tank and pull the pump out to make sure everything's in good shape. The "complete" pump would come with a new o-ring and stuff. I had one quit because the electrical connections inside the tank came loose, too.

Oh, and make sure to replace the sender float while you've got it apart. Or at least have one on-hand. Replace it if the original has fuel in it. I've had more trouble with those than anything else. They're only a couple bucks at the dealership.
Click to expand...


UDAMAN!

I also found a couple videos on youtube that goes through the entire process (thanks youtube!)
 
Not sure about this model, but sometimes it is easier to pull the bed off, instead of dropping the tank
 
if I had the tools and/or 6 more arms I would definitely pull the bed


....at least my driveway is concrete :LOL:
 
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