Fuel filter massive annoyance! Please help!

[doolish]

1993 325TDS SE E36 Manual

Ok here's the deal..

A few weeks ago, on my way home, I had a sudden loss if power and had to pull over. As I did the car stalled.

I crank the car a few times and get her started. Get home, everything fine for a while.

A week or so later the problem comes back and keeps happening.

I notice that there's air in the clear pipe that runs between fuel filter and engine. All if a sudden I stop getting any fuel at all through the filter.

I figure maybe it needs a new filter as the guy before me was running it on WVO.

Change the filter and flatten the battery trying to restart it.

Hook it up to another car to jump it and suddenly my fuel pump relay is ticking on and off (which did happen before, intermittently when I flattened the battery during a breakdown caused by no fuel getting through).

Relay fine. New fuel pump? Ok. Pump bought, fitted, car hooked up for a jump start, get life in the battery, can hear the new pump fire up (relay no longer ticking) but no fuel coming through. Fill the fuel filter with diesel and the car fires. Great. No. Car uses fuel in filter, pulls straight air through and stalls.

So I figure there's a block in the line.

This morning I turned the electrics on (but didn't try to start it) and the pump still sounded good. Thought I'd check the pump to make sure I hadnt left any stoppers on. No, all well. Put the fuel pump back in, turn the ignition lights on and the relays ticking again!!

I had originally thought I'd burnt the pump out trying to start it but this can't be the case this time because I didn't try to pump any fuel.

I should mention that all the time as the relay ticks the fuel 'spray' type light is flashing on the dash and before I changed the pump the interior lights flashed with it.

Also, if I blow down the pipes that connect to the top of the fuel pump I can hear the fuel bubbling. On one more than the other. Is that normal?

Any ideas what's next guys? Do you think maybe it's an electrical fault? (although I don't think that explains the fuel not coming through after I changed the pump!)

[Jack Dabsy]

Of the two pipes at the pump - one of them is the return-to-tank pipe and is not your issue...
Try installing a one-way valve into the fuel feed pipe to stop fuel being drawn backwards as the engine is off...
If you suspect an electrical fault, get a code reader. Could be a fuel relay or engine cut-off relay that is faulty!
TBH it could be a few things but I would say we're in the right area...
HTH

BTW you cannot "burn" a diesel pump out just by continuously starting an engine as it spins at a constant rate determined by the engine! You CAN however, have a failed pump seal which could have caused the initial problem... Go for the in-line one-way valve idea first as they are pennies to buy !!

[doolish]

Thanks for your reply!

I'll try the in line valve option when I get the pump running again, but for now have you any idea what can be causing the pump to fail?

I think my only option is gonna be to take it to a garage as I don't know zip about motor mechanics!

I don't understand how one minute the pump sounds fine and the next it isn't powering up.

[Novermyhead]

Doolish, Just purchased a E36 and I have been trying to learn all I can because it is a basket case. Watched a u-tube vid yesterday on how to install a fuel filter and there is an arrow on the filter for the direction of the fuel flow. So the arrow on your filter should be pointed at the engine.

This is something you have likely already checked, but as I said I am new and thought it might help. Best of luck to both of us!