my explorer started acting as if it were starved of fuel sometimes while driving... sputtering and acting as if it were going to die. Then it would clear up. It got proggressivly worse. I changed the fuel pump relay. No change. Then i changed the fuel filter which had a fair amount of trash in it so i thought that must have been the problem but when i got in to start it i turned the key off several times to build up the pressure and noticed i couldn't hear the pump buzzing like i could before and sure enough i had no pressure and the truck wouldn't start. So i went and got an in tank fuel pump and replaced it. Still no buzzing and no fuel pressure. So i finally did what i shoul have done from the beginning and i checked the voltage at the tank pump connector and it read just under 9 volts. the manual said it should be within 0.5 volts of the battery voltage. So i took the old pump and wired it dirctly to the battery and it fired right up. So my question is what could cause a loss of voltage between my relay and the fuel pump connector? Is it the PCM? is it the inertia switch? Is it somthing else? Or could it be grounding out somewhere inbetween a little bit? This is drivig me nuts. Thanks for any help.

 

My '92 did something like this. I traced it to a bad wire in between the fuel pump fuse and the fuel pump relay. The way to diagnose this is to start at battery, and work through the fuel pump circuit. Where the voltage drops off is where the break in the circuit is.