Ford: 1990 ford f150 5.9 lire fuel regulator, fuel pressure regulator, fuel regulator

Question
the truck will not start unless a live wire is put directly from the fuel regulator to the battery. Then it will start with the ignition switch. It will shut off and start as long as the wire is hooked up....Duane

Answer
Hello,


The 1990 F150 did not come with a 5.9

4.9 (straight 6 300CI)
5.0 (302 V8)
5.8 (351W V8)
and rarely
7.4 (460 V8)

none of thjese use an electrical fuel pressure regulator( they are all vacuum controllled), so, I am assuming that you are referring to the fule pump relay.


To assist you further, I would need to know, which of the 4 wires, you apply battery voltage to, to enable the truck to start?

also, without the wire hooked up and relay removed, Do you have battery voltage at the Yellow wire?, and (while cranking), at the red wire.