Volvo Repair: Volvo fuel pump, turbo volvo, citgo station

Question
I have a 1989 740 turbo Volvo that has been stalling out-running crappy.  I changed the in tank pump and it ran fine for one day. Now back to old tricks. There seems to be no voltage at the intank pump fuseor at the connection in the trunk.  Question, does the intank pump run all the time or only when needed? I changed out the relay to no avail. The main pump is quiet and func.  Thanks for any help. John

Answer
The fuel pump will run for a few seconds when the key is turned to position 2 and then cut out if you don't start the car, it will run in position 3 (start), and it will run continuously when the car is running.  If fuel supply is suspect, try to get a fuel pressure reading at the fuel rail, that will tell you more than anything else it should be pretty close to 300Kpa, and if fuel is the problem and the fuel pump was already replaced check the fuel filter; it sounds simple but sometimes its pretty easy.  The other thing to check is the quality of the gas you have in the tank.  I had a friend that just got 5 gallons of water at a citgo station so don't rule out anything.  Hope that helps.

James