Howdy,
My van has a remanned 305 and has had carb rebuilt and complete fuel system replacement in the past three years. Mechanical fuel pump had to be replaced again on a return trip from Florida to Missouri a year ago (mechanic didn’t believe it was the pump at first because of how well it was still running), and now it’s giving me the same symptoms again. Low power, cutting out under load, will stall if I don’t let it run for 5-10 minutes before takeoff. I’ve noticed both times the issues started after a quick change from cold to warm weather. Wondering if anyone has had issues with the Delphi pumps failing frequently. TIA.


Fuel leak at line connection circled.

 

The rubber diaphragm in there likely doesn't play well with ethanol in the fuel. Might be the same for that fuel hose.

 

I've also got a '84 G20, I go through a fuel pump about once a year. Those delphi pumps always seem to fail. I replaced mine again in January and it's already failing just a few months later. Gonna swap it out later today. This'll be the 4th pump I've gon through and I will say while it's a simple process, it's not fun at all due to the location of the pump.

 

I don't think it would be hard to change to an electric pump on these, you only need around 12-14 PSI out of it, just put a cap over the pump opening or take a bad pump and cut the lever off to cap the hole. That might solve the problem.