To determine if the issue lies with the fuel pump or the fuel pump relay in a 1993 Audi 90CS, start by checking for power at the fuel pump while the ignition is on. If there’s no power, the relay may be faulty; you can test the relay by swapping it with a similar one in the fuse box. If power is present but the pump isn't working, the fuel pump itself might be the problem. Additionally, listen for a humming sound from the fuel pump when the ignition is turned on, indicating it's functioning.
fuel pump relay, fuse or wires
Blown fuel pump fuse or defective fuel pump relay.
If you're getting power to the pump this proves the fuel pump fuse and fuel pump relay are good. That leaves only two possibilities. Either the pump is running but it's not pumping fuel. Or possibly the fuel filter is clogged.
If the pump is getting power but not pumping, it's probably a faulty pump. It's also possible that the pump pickup screen is blocked.
Blocked fuel line or SOCK (pickup) inside fuel tank-fuse 2 fuel pump OR anti-rollover switch that has been bumped or in a wreck.OR the hose that connectes the fuel pump 2 the pick-up tube inside the tak.or a bad fuel pump. 1st check to see it the fuel pump is getting power. If not check if power is getting to the fuel pump relay.
Check to make sure that the pump is getting power to the Neon fuel pump. Check the pump relay, and the pump fuses.
it is in the fuel tank
CHECK THE CONNECTOR THAT IS ABOVE THE TRANSMISSION. MY POWER WIRE TO THE FUEL PUMP WAS LOOSE IN THE CONNECTOR AND CAUSED THE VAN TO SHUT OFF. I FOUND THIS AFTER I REPLACED THE FUEL PUMP.
The fuel relay controls the fuel pump, so where are the bare wires? If the relay isn't getting any power then the fuel pump will never turn on, unless you want to bypass it to check the pump. If the bare wires are going to your fuel pump relay you have your problem... if not, either way, bare wires are a problem.
if after replacing fuel pump and still not getting power to the pump, check the crank sensor, this may have gone bad and quite often can be the problem.
Check all fuses and fuel pump relay. Check the fuel pump inertia cutoff switch in the trunk.