I need help on a fuel pump problem.

F-150
1990
4.9L 6Cyl Engine
291k Miles

This truck has duel tanks. The front tank fuel pump went about 3 years ago. Now the rear tank pump has quit.

Today, we pulled the old pump after dropping the gas tank. (It was too hard to get the bed bolts off.) Pulled the pump. Got a new one at Autozone for $150. Added it to the assembly and connected the internal wires. We put the pump back into the tank and connected the fuel lines and the electrical connection. But I still do not have it working. When I turn the key, I don't hear the pump starting.

I have checked the power at the Fuel pump relay under the hood by the Air Filter. I have about 11.7 volts going in and coming out.

I check the voltage going in at the rear pump and it is only getting about 3.6 volts. Is this enough to run the pump? Is there something between these two sources that could be causing the problem? I am at a loss at this point and really don't want to take to someone.

Anyone know what may be causing this or had any similar problems?

Thanks for any help,

Donnie Penney
dwpenney@dwpwebsites.com

 

You should be getting battery voltage at the pump. if not, you could have a bad ground or corroded connection somewhere between the pump and the source.