DarkNite

Just put a new battery in my 1991 F150 Nite, went to fire her up and blah.... The fuel pump wont shut off and the truck wont crank. Its an EFI with the 5.0 in it, 4x4, with the E4OD tranny in it.

Thanks ahead of time guys.

Good old Bill

Am very concerned for you! Does the engine turn over by hand using a socket, breaker bar attached to crankshaft balancer bolt, if it doesn't, remove all plugs and see if it turn now. This engine could be hydraulically locked with fuel.

DarkNite

The engine does turn over. Im sorry I should have been more descriptive in my opening post.

The engine turns over and over and over but just wont fire off. Just like if you were to press the shut off switch of the fuel system and try to crank it. BUT I checked that and its on. You know how you turn the key to the on position and you can hear the fuel pump turn on as it fills the lines and injectors and then you hear it shut off.....well it dont shut off.....

transmaster

It sounds like the constantly running fuel pump is over pressuring the system this will cause the injectors to leak and flood the engine. Check 3 things the pressure regulator the fuel pump relay. and the Power Control Module. Because the PCM controls so many things this would be something I would check first.

Your Truck is an OBD1 have you had the codes read.

Just call me Sean

iTrader: (1)

You can read the codes yourself with a piece of wire. This will tell you how:
https://www.f150forum.com/f10/how-retrieve-trouble-codes-obdi-10907/
Get the codes and post them here first.

DarkNite

Thanks guys! I Really appreciate your help so far. I towed it up to my mechanic shop for them to diagnos this and some other problems. I will post more info as I get it to see if I can fix it myself.

Again THANKS guys so far!!!!!