Trouble Shooting Efi Fuel Pump (power)

[casadejohnson]

My EFI conversion left me stranded this weekend. I was up in the mountains cutting a christmas tree and the bronco started cutting out on me. I started to head home and it died completely. I pulled a fuel line and found that I was not getting fuel from the pump. I figured I had a bad pump but once I got home I found that the fuel pump bench tested fine and that I was not getting power to the fuel pump. I checked the fuel pump cut off and it was ok too. just to be sure, I used a jumper wire and bypassed the switch. I have not pulled any codes yet because the battery went dead trying to get it started. Any Ideas what would cause this?

 

[Bronco Brian]

I had the same problem with mine it work then quit thought I was running out of fuel left me stranded a few times. changed the pump new one has not let me down (2 yrs.)

 

[SaddleUp]

I've had the FP relay go bad 3 times now. One of these days I'll move it somewhere that doesn't get water splashed into it. One of the three times it was letting a trickle through that made it appear to be getting power until it was in use. Then it would fail. At any rate you might try swapping the relay and see if that fixes it.

 

[casadejohnson]

Saddleup-

I had that same thought about the relay last night. I swapped it out and it worked fine. Fuuny thing is that When I was swapping relays, I put the original one back on and it works too. I think I may have just had enough dirt and grime in it to cause a bad connection.

 

[SaddleUp]

Good deal. Keep that spare relay handy though.

Mine was pretty interesting the second time it failed. It really didn't fail as such but rather it turned the fuel pump on by itself. I walked out one morning and heard the pump running. I switched the ignition on and off and it shut off. The next morning I walked out and it was on again. I swapped the relay out and that fixed it.

 

[tj]

I've had the FP relay go bad 3 times now. One of these days I'll move it somewhere that doesn't get water splashed into it.

That makes me glad I installed mine where I did. Not having any experience with EFI, I wanted the impact switch to be in easy reach while rock crawling so it and the FP relay are well protected inside the cabin where it can be reached with one hand still on the wheel. Since I didn't trust the impact switch, I added a LED in parallel with the electric fuel pumps so if there is no power to the pumps the LED goes out.

On the other hand, I had a EEC relay go out on me 3 days ago. It rattles inside. I'm beginning to mistrust Ford relays but am learning how to troubleshoot EFI in the field. Luckily I had my wiring diagrams, a volt meter and short jumper wire on board. I just put a wire between the two relay contacts in the socket & drove home.

So now I know to carry spares of both the EEC and FP relays.

 

[Broncl]

I'm getting in a late reply, but I had similiar problems before I added a fuel accumulator. When the tank got down to around 1/4 I would pick up an air bubble when I acclerated and run out of fuel. I then had to purge the line to get the air out before it would start and run well. If you don't have an in tank fuel pump and are running two pumps as I am and you don't have the accumulator I would suggest you get one. I've had absolutely no problems since