Volvo Repair: 1991 volvo 940se, fuel pumps, power stage

Question
I need info on the fuel pumps and how they operate the car quite on the way home from work, after I got home and in the garage I chech the relay it's working fuses are good but the car won't start, I thought the sensor behind the engine had gone out well I decided to run a pair of wires from the battery to the pump under the car and then tried to start the car it started without a problem. what's the problem is it the pump in the tank.
thanks
Dan

Answer
Dan, Which relay did you check?  There may be 2 on your car.  One is the fuel relay behind the ashtray and the other is the black IGN relay in the engine compartment.  There is also the speed sensor that you know about and also the ignition power stage by the air box. The in-tank pump will not not make the car run, it basically helps the main pump from over doing it.  You have a few issues here.  
check for spark, etc.  We can go further if you want.  Roger

Dan, Thats what I needed to know.  Bypassing it will cause it to run.  You have to check all other things.  You arent getting a signal from somewhere causing the car not to start.  Its very hard to diagnose these sort of issues without seeing the car.  I can only give you suggestions.  Roger