Many thanks to the replies to the previous post, however I'm yet to find what course of action to take if any is needed.

As further details of the car may help its a 1989 740Turbo B230ET Motronic Fuel Injection.

Symtoms are main pump and tank pump appear to be running continously, even when engine is stopped in Ign switch postion 2 a buzzing can be heard under the car, and fuel is being returned to the tank by return line.

What should happen? Is there a mechanical? or electrical fault?
I've since found out previous owner may have done some soldering on Fuel Relay PCB and don't know what else?

Would the Relay be at fault? Is this normal operation for this car?

As I posted previosly have checked Tank pump(heard working through filler) but not checked sock or rubber hose, and not sure if they were faulty that this would be the problem here? Have also checked fuel regulater(constant stream of fuel to return pipe and no real smell of gas on vacuum line side)the fuel still returns in Ign switch postion 2 with engine off.

I'm going to replace the filter and some vacuum hose that looks a bit dodgy as well.

Do I have a problem here? Any more help would be appreciated, especially what order I should check things in? either mechnical or electrical.

If somebody elses car does the same it would be great to here from you?