Safety First!
* Work in a well-ventilated area. Gasoline is flammable and can be dangerous.
* Disconnect the negative battery terminal. This prevents accidental electrical shorts.
* Use appropriate personal protective equipment. Wear safety glasses and gloves.
Testing the Fuel Pump
1. Locate the fuel pump. The fuel pump is located in the fuel tank, under the rear of the car. You'll need to remove the rear seats to access the tank.
2. Access the fuel pump wiring connector. On the 1984 928, the fuel pump is controlled by a relay. This relay is located in the engine compartment. Disconnect the wiring connector from the relay.
3. Power test the fuel pump. Connect a jumper wire from the positive terminal of your battery to the fuel pump's positive wire terminal in the connector. Connect the other end of the jumper wire to the negative terminal of your battery.
4. Listen for the fuel pump. If the fuel pump is working, you should hear it running. If you don't hear anything, the fuel pump may be defective.
5. Check for fuel pressure. If the fuel pump is running, you can check the fuel pressure with a fuel pressure gauge. The gauge should be connected to the fuel line at the fuel rail. The fuel pressure should be between 35 and 40 PSI.
Troubleshooting
* If the fuel pump is not running, check the relay. You can test the relay by swapping it with a known good relay.
* If the fuel pump is running, but you don't have fuel pressure, check the fuel filter. The fuel filter is located in the fuel line between the fuel tank and the engine.
* If you have fuel pressure, but the engine is not running, check the fuel injectors. The fuel injectors are located on the fuel rail.
Important Notes:
* Do not attempt to run the engine with the fuel tank open. This could lead to a fire.
* If you are unsure about any part of the process, take your car to a qualified mechanic. Working with fuel systems requires experience and knowledge.
Let me know if you have any other questions!
