No electrical power to fuel pump - 89 F-150
Asked by russdward357 May 19, 2010 at 12:33 PM about the 1989 Ford F-150
Question type: Maintenance & Repair
Hi, this truck suddenly started cutting out after running about 30 seconds. I have discovered that there is no power at the exterior (main) fuel pump connector when the key is turned on. When I short the relay with the test ports under the hood, the relay clicks and the pump runs. My main question is... is there ever a reason why the fuel pump should be unpowered when the key is on? I'm thinking no, therefore I might be looking at a PCM problem, yes?
BTW it's a 302 EFI with dual fuel tanks.
5 Answers
sounds like your pump has gown out.
Well, the relay could click and still be bad. For a $5 dollar part I would just replace it to be on the safe side. Also check the fuses to the fuel pumps. Are they good? If good there as well, check for fuse links in the wires running from the fuel pumps, Ford is bad about putting these redundant safety features in there. If all is still good try to run a straight wire to check the pump is good. If pumps is good chances are more likely then not that the PCM is bad.
russdward357 answered 14 years ago
Thank you both for the replies. I have reseated all plugs and replaced the relay. Now, when I turn on the key, I hear the pump run for a second. There was corrosion on the relay pins, so perhaps it was something like that. Anyway, I think perhaps something got fixed along the way. While I'm at this, I will replace the (very old) fuel pump, put it all back together, and let you know what happens. One curiosity... at one point, I turned the key and heard the in-tank pump running too. Now I don't hear it running. I'm not sure what might have changed. But anyway, thanks again for your help.
Just replaced front fuel tank and pump with a new high pressure rail pump and no fuel pressure don't think it's getting power to pump can't figure it out it's a 1989 Ford f 150 duel tank not using rear tank at this time needs to be replaced truck will run if you put gas through cold air intake
You may want to check your tank switch. The switch on your dash changes sending unit input and it may change which pump runs. I'm not sure if there is a solenoid valve to switch fuel flow or not.
