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?

Look at the fuel pump relay--it sounds like it could be stuck in the on position-you may have to repalce it or find the source of the power which sounds like itcould still be on too and thus sending power to the relay---I wonder if the ignition switch is bad thus causing the whole sequence to be messed up? Hope this is of some help!

if so, your FPR may be mucked up and your computer may think you need A LOT of fuel in the system causing the pump to work overtime. If this is the case your engine should be running very rough (too rich).

If it's not thus, I've no idea, but it doesn't sound normal to me. Probably an electrical fault somewhere.
--
Six Volvos: all wagons.... 1972 145S, 1976 245 DL, 1983 245 GL, 1986 740 GLE, 1990 740 GL, now a 1995 940. Number 7 (a 1967 122S Wagon) is on the way.... Who needs a sedan, when you've got storage compartments in a wagon?

What market are you in that you are running a B230ET with Motronic? I have never seen one but there is a schematic for it in the book. If the pumps run continuously then I can only assume that they are being powered up via the relay. The relay gets it's power through fuse #1 which is hot all of the time. When the key is turned on it provides power to the first coil in that relay which is permanently grounded, this closes the first set of points which allows current to the second coil, when the control unit sees an engine speed signal it will ground the other side of the second coil and close the points which should allow power through to fuse 11 which feeds both or your pumps. All that technical mumbo jumbo being said I would look for a grounded yellow/black wire on the bottom side of that relay, should be in position #4. If you ground that wire the pumps will run any time the key is in the on or run positions.

This is a pretty typical fault in the '89-'90 year model 700 series cars but they were all LH. Do the Motronic units have the same problem? I do not know. Is this a problem? Well if you run the car into a phone pole and you are trapped in it and the fuel pumps are pumping fuel all over the ground and you die a fiery death because of it, well then yes I guess it is a problem. Otherwise don't worry about it and run it the way it is. Myself though, I would fix it.

Mark

Hi Mark,

Thanks for your reply I,ll investigate it further.

I'm in the UK so its an European model, I've checked in the
Haynes manual I've got for the car, and it said the Fuel Injection system
is "Motronic system" basically Bosch L-Jetronic fuel injection with integrated
ignition system control".

I,m not sure if this makes any difference to your trouble shooting technical advice?