80 230E - New Fuel Pump still Screams?

[Dave Alex]

The car's original fuel pump began humming louder and louder as the years passed. The car is only started and run about once a month. This month the fuel pump failed completely. I removed and tested the old pump, dead. I replaced it with a new pump and a new fuel filter. I also drained the gas tank and inspected the fuel. Nothing of interest. On start-up the new fuel pump began to scream after just a few seconds of running. I suspected the aftermarket brand pump was faulty and took it back. A second pump of the same brand did exactly the same thing. I then paid the price for an original equipment Bosch pump. It too gets louder and louder the longer it runs and after 5 minutes the engine hesitates and will stall. Let the car sit for 5 minutes and the symptom will repeat itself. I am at a loss for what to look for next? Thanking you in advance.

[97 SL320]

Did you pull the fuel strainer from the fuel tank and replace it? It is likely clogged.

[clarkz712]

You are lacking fuel check for restrictions going to the pump like the screen in the tank.
quick test for plugged screen would be to remove gas cap and then remove fuel hose from tank to pump and blow air towards the tank then put back together and see if noise is still there if noise is gone replace the screen in tank and your good