1991 F-150 supercab, 4x4, blown fuel pumps. has one new pump installed after this last weekend. has new fuel relay, and EEC relay installed also. fuses are fine, but seem to have no power to emergency shut-off, or to fuel selector switch. cannot find a ground problem. also, no power to either front or rear pumps. turns over fine, but will not start. anyone out there with an idea? after many $$ in new parts already, getting ready to give up. got loan paperwork laying here on the desk.

 

It might be a fuseable link.
Did you check for power at the relays?

Can you pull codes? Even a 'no codes' code will let us know the computer is probably ok and getting power.

Popa Tim

 

did not find a fusable link at all, and can get a friend to check the codes, but kinda figured it wouldnt do much good. where would the fusable be located at? never saw one, and went thru it again last evening with a flashlight. thanks for your help buddy

 

did you check for corrosion under the power dist. box?

did you try to hot wire the fuel pump to see if it worlks.

 

I would check for power at the relays first. They should be fed 12v with the key on. the Fp relay sends power to the pumps when the EEC grounds its pin 22.

You do realize that there is only FP power for 2 seconds when you turn the key on right?
The eec wont send power unless it detects PIP thereafter.

Popa Tim

 

thanks guys, for all this info. will look into all of it. its going to a friends shop to get put on the computer, and will know more after that. if ya have more ideas, sure will love to hear them. if anybody needs ideas about being mechanically illiterate, i can sure help with that---lol.