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1958 Cadillac fuel problem

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Hello everybody,


I am becoming frustrated beyond believe with my fuel system.

Last year my car left me stranded with a defect fuel pump. I bought a brand new replacement one and it was working ok for the rest of the year. Then, two weeks ago after a car show, the car started up, but died after about 30 seconds of idling and would not start anymore. After I pushed the car out of the street and called AAA (about half an hour later) I tried starting it again, and oh wonder, the engine started and kept running so that I could make it home on my own power.

The next day I checked the fuel supply (using a hand pump I was able to suck gas from the tank with no effort - so no clogged fuel line), took the fuel pump out and bench tested it (getting a good fuel flow). Once installed again, the glass bowl fuel filter filled up ok with no visible bubbles and the engine ran great (idle and driving).

Today I drove to a car show and the car behaved normal until 3 miles into the trip: the engine started hesitating, like being short on fuel. After pumping the accelerator a few times, it cleared up and the engine kept running without further issues.

Then after the show, I started the engine, it fired up, but died after a few seconds. I checked the glass bowl fuel filter, but it didn't fill. So I took the fuel line off and sucked on it (with an extension and felt the fuel coming). Then I took the fuel line to the carburetor off and cranked the engine - no fuel being pumped! So I took the pump (less than a year old) out and replaced it with a spare pump (was rebuilt with ethanol resistant new components). Once the fuel reached the carb, the engine immediately started up and I made it home with no further incident.


What are the chances that a fuel pump goes bad in less than a year? Could it be that the pushrod or the cam driving the pump are worn, reducing the available stroke when hot? I am grasping at straws and looking for a solution other then changing the fuel pump every few months...


The car has issues with vapor lock when hot (hard starting when hot), but so far (until the last car show), I was always able to get it started again.




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Hello 62 driver,


You were onto something. When I disassembled the pump today, I found one of the valves had become unseated, bypassing the system. Only pressed in, not even staked, either. So when the pump became warm, it came lose and when the engine cooled off, it wedged itself in again until it came lose again.





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