How do you know when fuel pump bad?

Answer 1

Disconect the air intake behind the MAF sensor. Have someone start the car while you spray starter fluid into the intake, if the car starts you are not getting fuel to your fuel rail. Check the fuse to see if it has blown. Check the fuel filter to see if it is clogged. If these check out test the fuel pump relay. Look at the diagram on the relay to see wich terminals are the switch and wich are the coil. If it is a European car the terminals on the relay are numbered with 30 and 87 being the switching terminals. Use a jumper to bridge the slots where the switching terminals are and walk to your fuel tank. If you hear the pump come on the problem is probably your relay. Remember to pull the jumper off before too much time so you don't overpressurize your fuel system. If the pump does not come on disconnect your battery ground and follow the instructions in your manual to remove your fuel pump. You can further test the pump out of the car by hooking it up with jumpers to your battery ( don't mess up the polarity) to see if it turns on.