Fuel pump dying on 73 2.0L

[Conrad W Peden]

What is the most common failure mode of our fuel pumps?

I have one that runs when the key is turned on but wont run the engine.

Then wont run with a turn of the key. Then will, but not with its usual gusto, and not eough to start the engine.

Then it will run the car for a quarter mile or so.....but never enough to get me home at 10pm sunday night


Any thoughts?

[swl]

I've had a failed one apart to have a look. Pretty simple pumps. The part that caused mine to fail is the pop off valve. I think it is suppose to do two things. Keep the gas from draining out of the fuel rails when the power is turned off and assist in priming the system by bleeding off air. When mine failed it was constantly in bypass mode - fuel being returned to the tank instead of the rails. The pop off is held closed (bypass) by springs. There has to be fuel pressure to defeat that spring. There is a rubber tit on the end of the valve that seals the bypass. With age mine had become misshapened and was sticking shut.

After much farting around I came to the conclusion that it was a lot easier to just replace the pump. Couldn't find a rebuild kit.