Fuel pump blowing not sucking!
#1
Fuel pump blowing not sucking!
Recently replaced my fuel pump on my f250 with a 400. Diagnosing a no fuel problem and hooked my fuel pump vaccum gauge thingy up and seen that its making vaccum at the output side, and pressure at the input.... Took the new one out and simply pressed down on the arm...yup blows air out of the input side. Got the old one...sucked my finger right to it with one press of the lever. What would cause a brand new fuel pump to do this? All I can think of is a broken diaphram or something?
Thanks
Thanks
#2
Wrong fuel pump perhaps? Or, built incorrectly?
The only engines that this fuel pump goes on is a 351M/400; they're pretty unique. But maybe there's some unique difference between pumps built for cars and pumps built for trucks in terms of inlet and outlet orientation. That seems like a stretch though.
The only engines that this fuel pump goes on is a 351M/400; they're pretty unique. But maybe there's some unique difference between pumps built for cars and pumps built for trucks in terms of inlet and outlet orientation. That seems like a stretch though.
#3
Wrong fuel pump perhaps? Or, built incorrectly?
The only engines that this fuel pump goes on is a 351M/400; they're pretty unique. But maybe there's some unique difference between pumps built for cars and pumps built for trucks in terms of inlet and outlet orientation. That seems like a stretch though.
The only engines that this fuel pump goes on is a 351M/400; they're pretty unique. But maybe there's some unique difference between pumps built for cars and pumps built for trucks in terms of inlet and outlet orientation. That seems like a stretch though.
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Recently replaced my fuel pump on my f250 with a 400. Diagnosing a no fuel problem and hooked my fuel pump vaccum gauge thingy up and seen that its making vaccum at the output side, and pressure at the input.... Took the new one out and simply pressed down on the arm...yup blows air out of the input side. Got the old one...sucked my finger right to it with one press of the lever. What would cause a brand new fuel pump to do this? All I can think of is a broken diaphram or something?
Thanks
Thanks
Check the hose on the inlet as well. The inside of the hose can delaminate and act like a valve at highway speeds.
jim
#10
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