mechanical fuel pump sudden (overnight) failure

[80goldenburb]

A few days ago i went to warm up the truck when i noticed the fuel filter went dry with seconds. i put 3 gallons in that in a spare can, and some in the carb fuel bowl ran for 3 seconds and died, no fuel pumped at all. Did this about 6 or 7 times and i finally decided to hook up the inline electric pump to get her runnin'. The mech pump is a 3 port from Autozone, only 5 months old, the return is capped off. Any ideas?

I have had Pontiac 400s and Cadillac 500s with mech. fuel pumps that lasted years and never failed suddenly like this.

 

[1987 GMC Jimmy]

Well, I'd suspect the pump for sure. The diaphragm in the pump may have just kicked the bucket prematurely. Is it a Delphi? Those are made in South Korea, which is not nearly as bad as some places that parts are made, but I still trust parts made in the good ole U.S. of A over anywhere else. You could pull the pump and make sure the pushrod is okay as in not bent or otherwise damaged. Literally the only other thing involved in this process is the camshaft eccentric lobe. I doubt it's wiped, though. The first place I'd look is the pump and then the pushrod while you have the pump off. If you've gotten rid of your return system and need a pump without a return, I know an '85 Caprice and probably earlier have a returnless pump.

 

[PrairieDrifter]

That fuel pump will never bend lol. It might wear down or shatter but it wont bend

 

[74 Shortbed]

Make sure all hoses and fittings are tight, could be sucking air someplace??..

 

[smoothandlow84]

Bad diaphragm would be my guess.