De pomp onder de auto maakt herrie als de tank niet zo vol meer zit. Dat zou oa kunnen komen doordat de in tank bezinepomp niet meer werkt.

Omdat het ook door andere oorzaken zou kunnen komen wil ik graag controleren of die in tank pomp nog werkt.

Op brickboard staat:

Fuel Pump and FI Relay Diagnostic Tests.  Here is a procedure to test the operation of the fuel injection relay and the operation of both fuel pumps.  The 3 main things to check in the fuel circuit are the fuel pump relay, and the 2 fuel pumps.

1.  Fuel Injection Relay Test.  There are 2 relays inside the fuel injection/pump relay. One of them should turn ON when the ignition is turned on (without turning over the engine), and the other relay (which actually turns the fuel pumps) should come ON when the engine turns over/runs. You can check the 1st relay by putting your fingers on the relay module and turning the ignition on and off repeatedly. You should feel the relay click on every time. If it doesn't, that relay isn't working. And you'll find the car doesn't start if the relay did not come on.
 2. Fuel Pump Diagnostic Tests.  On the 740, the fuse-box + relay box can be pulled out a little to facilitate inserting/removing relay modules. So pull it out as much as the wires will allow. Pull out the fuel injection/pump relay module. Now take a small piece of wire to jumper terminals 30 and 87/2 on the relay board (the terminals are identified on the relay module pins. The 2 terminals are the nearest left and middle right pins on the relay board). This should make the car act like the fuel pump relay is ON.

Now turn the ignition ON (without turning the engine). You should hear a whirring sound right from where you are. That will be the main fuel pump. Now go to the gas tank and unscrew the cap. Put you ear to the hole and you should hear a smaller whirring sound. Or, listen with a piece of heater hose to the tank pump through the gas filler with car running. Should hear a humming. That will be the in-tank pump. If you hear both noises, the fuel pumps should be OK.

To check the pumps individually, you can pull out the in-tank fuel pump fuse after you do the above test, and repeat the test.  You should not hear any whirring at the tank, but you should be able to hear the main pump.

CAVEAT: The main fuel pump is not designed to be run without the in-tank pump "on", so get the second part of this test over quickly.  You should not need to keep it running in this condition for more than a few seconds to complete this part anyway.

De vraag is alleen of dit ook op gaat voor een Volvo 940?

Andere testmethodes zijn van harte welkom!