Fuel pump issue on 1990 300TE 12v

[Mat_b]

Having susspected a knackered fuel pump, (making knocking noise) just discovered a 2nd fuel pump near to it, do these both come off the same relay and run at the same time? Will they both need replacing?

 

[television]

Having susspected a knackered fuel pump, (making knocking noise) just discovered a 2nd fuel pump near to it, do these both come off the same relay and run at the same time? Will they both need replacing?

The twin pumps was an update on the larger single fitted to the earlier cars.

They are both in parallel electrically and with the fuel.

The fuel filter in line with the output more than likely was never been changed.

The car should run on either, take the wire off one pump and the car should run, then put it back and do the same with the other one.

These pumps can sometimes be brought back to life by running them backwards with the pump section emerged in diesel

 

[Mat_b]

Thanks to television for your reply, today I wired up pump nearest tank to battery to eliminate relay etc issues and found it would start but wouldnt run over 2000rpm, I then had a closer look at second pump and found a broken wire, rejoined it with a crimp connector, car now seems ok, just going to run it round block, bit worried about first pump sounding knackered, Ill probaly disconnect first pump and see if it runs on second only, they seem to be run in series

 

[television]

Thanks to television for your reply, today I wired up pump nearest tank to battery to eliminate relay etc issues and found it would start but wouldnt run over 2000rpm, I then had a closer look at second pump and found a broken wire, rejoined it with a crimp connector, car now seems ok, just going to run it round block, bit worried about first pump sounding knackered, Ill probaly disconnect first pump and see if it runs on second only, they seem to be run in series

Just do as I said with the pump that is not running, with the diesel, you will have to replace it if it does not work otherwise you will get fuel starvation at the top end