I have a 92 f-350 with the 4.9 auto. I have a problem were the fuel pump will not always start when the key is turned. I replace the pump but it still happens. It does not do this all the time,however sometimes I turn the key up to 20 times for the fuel unit to kick in. I know were the relays are yet I do not know which one it is. Any ideas?

 

There are a couple of relays there that are the same. Sometimes switching them will correct a faulty connection. You could also remove them one at a time and when you don't hear it drop out you know you found it.
The computer is supposed to energize that fuel pump relay for 2 seconds unless you crank the engine over then an RPM signal is supposed to keep the relay energized.
You do need to wait a few seconds between tries if checking the 2 second thing.

 

This truck is not running at all. what would happen if I hot wire the pump and run it that way?

 

Does the truck run alright when you "hot" wire it?

 

Hanky thanks for your help. I have three relays there. One was the horn, one was the fuel circuit, and one the fuel unit. The one that pulled in the unit was bad(changed it out with the horn for now) and the truck starts and runs great.

 

Good work. If you mark the relays while it's still fresh in your mind, if you should ever need to remember them the marking will help. As you know, if you mark them they will probably never give you any trouble again. But, don't, and after you forget, guess what?