a guy at work gave me his 91 f150 300 5 speed. it has 200k miles on it. he drove it daily untill one day the battery died while at work. he put a new one in it but reversed the terminals. it melted some wires on the pass side fender. we replaced the wries, not the solenoid, and it would start, but it would die right away. he towed it back to his apartment and never had time to do anything with it, so he gave it to me. i took it to my house, put a battery to it, and it started right now. ran good but it had a lifter tick, so i shut it off, put some oil in her, and tried to start it. nothing. i noticed that the fuel pump ran constant when i put a battery to it. any clue whats wrong with it? please help.

 

For a free truck , a wiring harness shouldnt be to high a price to pay.

 

which harness?

 

this is too funny, had a very simular thing happed to a friends car. Nissan stanza

I started checking things out and found no power to the fuse box, then no power to one of the fuseable links. I made a jumper from another fuseable link and it worked great. then all of the sudden, it started working again without the jumper, he drove it around, came back and it died, jumper back on, worked again.

It looks like a breaker was setting / resetting and this was giving / taking power to the computer and fuse box.

I'd start with a long test light (2.99 @ harbor freight) find out if power is getting to the computer, fuse box, links ...

You can make a jumper and steel power from another source to continue testing things, this should isolate the problem.

then just get a harness segment from the junk yard, or re-wire the bad parts, or just use the jumper as a substitute.

The problem with wiring is that it's a major pain to replace.