Fuel pump keeps going out

Cougar Community Classic Cougar Maintenance Restoration and Repair
1

I’m on my 3rd fuel pump on my 1968 289, the first one was to replace the very old one that came on the car. The second one I replaced was new from Napa and that one lasted maybe 200 miles, the last one I replaced also had a very short life but was under warranty so I got another at no charge. These are the stock mechanical type, nothing fancy. I think the issue with the very first replacement was my fuel tank was not vented and caused the fuel pump to have work extra hard leading to early failure.

I drilled the fuel cap to eliminate that issue but then the fuel pump failed again. I don’t see any debris in my inline filter to the carb so I’m not sure what is going on. The fuel line from the tank isn’t blocked and I back blow it with compressed air to make sure when I change these out.

I thought about going to an electric fuel pump but these mechanical should last for years :thinking:

Any clues on this one?

1 Like
2

I wonder if the fuel pump eccentric is the correct diameter?

Ethanol fuel may be incompatible with your diaphragm.

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Specific failure mode(s)?

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First one I changed was leaking pretty bad, the second one the diaphragm must have went since I couldn’t feel any suction when operating the arm, the third one felt like the was suction and diaphragm was still working but the carb wasn’t getting gas. As soon I changed it I was back in business…..but for how long?

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Smashed fuel line beneath the car can cause fuel pump suction issues. I chased something similar on my Tbird for months until I took a real close look at the tank to pump tubing and found where someone smashed a very small section (likely from a floor jack).