EFI Fuel Pump Not Working

[kahuna bill]

Can't fire off the fuel pump under normal ops.
i manualy toggled the relay via the star connector under the hood. the relay clicked open and closed. i read the voltage at the pump connector and it read 12 volts. i have a spare pump/sender unit that works. I plugged that in and still no luck. I've looked at all my ground connections and they're attached.
It rained a lot down here in So-cal in the last week and that's when the truck crapped out on me. It stoped working after i turned it off and tried to fire it off the next morning... never had any indication of failure of any parts.
I'm going to replace the relay just for S^*#s and giggles, and i have a spare computer i'm going to throw in to see if that might help...
But i'm sure that's not going to help... do you guys have any ideas ?

[philofab]

Can't fire off the fuel pump under normal ops.
i manualy toggled the relay via the star connector under the hood. the relay clicked open and closed. i read the voltage at the pump connector and it read 12 volts. i have a spare pump/sender unit that works. I plugged that in and still no luck. I've looked at all my ground connections and they're attached.
It rained a lot down here in So-cal in the last week and that's when the truck crapped out on me. It stoped working after i turned it off and tried to fire it off the next morning... never had any indication of failure of any parts.
I'm going to replace the relay just for S^*#s and giggles, and i have a spare computer i'm going to throw in to see if that might help...
But i'm sure that's not going to help... do you guys have any ideas ?

Check voltage under load, I.E. while the pump is hooked up. A bad connection at a connector will show voltage until a load is placed on the circuit. If it fails at the pump follow the circuit back to the relay, then to the relay control and the relay supply. Don't forget to check the ground under a load too.

[kahuna bill]

awesome, thanks philo!
had 0 volts at the pump under load and followed it up to the relay... and that's where the problem was. i could have sworn that the relay was good becuase i could hear/feel it toggle open and close, but that was when it was unloaded. anyways, i replaced it and the pump is working just fine.
Thanks again, and Merry Christmas!

[Dezertbronco]

does it have a crash sensor?

[kahuna bill]

sorry it's taken me so long to get back to your question... was out bashing the bronco around ocotillo for the new year and creating a new batch of problems.
i'm not sure what you mean by crash sensor? but if you are talking about the fuel shut off on the fire wall that goes opens the circuit in high G circumstances? than yes i do. super easy to reset and that was the first place i checked. working just fine.
it was the fuel relay that screwed me up. there was enough corrosion on the connections to cuase 0 volts at load, but still read 12 volts unloaded.
but thanks again for all your help. hope y'all had a good new years. Cheers!

[lifeinthesouth]

I think my fuel pump is dead.

I was unable to start my truck (95 bronco 5.0/E4OD) last night. It cranked and turned over fine but wouldn't start; i tried again just turning key to ON position and the fuel pump didn't prime.
I checked all fuses, inertia switch and swapped in a known good relay and still no luck.

It has been running fine with the exception of once last week it turned over but wouldn't start... i waited 2-3 min and it started right up.

Is there anything I'm missing or would you guys agree it's the fuel pump?

Thx --Mike

[bajascott]

sounds like the pump.

[lifeinthesouth]

thanks Scott

[SteveG]

Have someone crank the engine over while you pound the gas tank with a large mallet. If the fuel pump starts working then you know the pump is bad.

[lifeinthesouth]

i'll give that a shot