I took my 1991 f150 fuel pump out because it burned up. I bought a replacement pump took the assembly apart and reassembled it. The pump fires right up but doesnt pump it sounded like free revving. So I took it out and put it in a bucket of fuel still the same, I don't think the gas is getting into the unit. My question is do I need to put fuel into the sending unit to get it to prime?

 

I guess Im asking do I need fuel inside of the pump assembly to pull more fuel in?

 

You may have wired it backwards. If you did have to wire the plug then you may have it pushing instead of pulling.

 

Thats what I thought first but I checked that already. I noticed tonight that there is a red flapper door behind the fuel sock. It acts as a one way valve it goes in but wont flap out. I think I need to fill the case that the pump sits in with fuel to instigate suction. Im kinda at a loss though this would happen when you ran out of fuel too.

 

You shouldn't have to prime the pump, or fill any area with gas.

 

got it to work in the bucket I sprayed some wd-40 into the case and it finally sprayed out some gas! I think I need to take it back apart and clean the flapper valve though cause I think its sticking. This pump assembly has been festering in 8 year old gas.