I have a 91 f150, 302, was driving, it died, checked fuel rail, no pressure. Figured fuel pump shot. Pulled pump, hooked to battery, it runs. Replaced both, eec & fuel pump relays. Jumped relay on 3&4, pump didn't work. Inertia switch not tripped. Checked voltage at pump plug, only got 8.5v to power & sender. I've read alot about fuel pump problems tht are similar but nothing exactly like this. What could be reason to only have 8.5v at pump plug? What else can I try & what am I overlooking. All fuses good. Grounds tht u can find and/or know about seem fine. Any ideas?! Thanks in advance

 

Check for that 8.5 volts with the pump actually plugged in. I'm betting it then will drop to zero, and you have a bad ground. What is the value of resistance in ohms from the negative side of the pump to a jumper wire up to the negative battery terminal?

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