1. Listen for the pump:
* Key On, Engine Off (KOEO): Turn the ignition key to the "ON" position (but don't start the engine). You should hear a brief whirring sound from the fuel pump. This sound usually lasts for a few seconds. This sound indicates the pump is receiving power and priming the fuel system. If you don't hear it, the pump may be faulty, or there might be a problem with the power supply to the pump. The sound might be faint and difficult to hear; you may need to listen carefully near the fuel tank.
2. Check fuel pressure:
* This is the most definitive test: You'll need a fuel pressure gauge designed for automotive applications and the correct adapter for your vehicle's fuel rail. Consult your repair manual for the correct specification of fuel pressure. Connect the gauge to the fuel rail (you'll likely need to relieve pressure first before connecting the gauge). Turn the ignition to the "ON" position. The gauge should show the specified pressure. Then, crank the engine. The pressure should remain stable while cranking. Low or no pressure indicates a fuel pump problem.
3. Visual Inspection (Less Reliable):
* Check the fuel pump relay: Locate the fuel pump relay in your fuse box (consult your owner's manual). Visually inspect it for any signs of damage or corrosion. You can also swap it with a known good relay of the same type to rule out a relay problem.
* Check the fuel pump fuse: Similarly, check the fuel pump fuse (again, consult your owner's manual). A blown fuse will prevent the pump from working.
* Inspect the wiring: Visually inspect the wiring leading to the fuel pump for any obvious damage or loose connections. This is more difficult as the wiring usually runs along the frame and often to the tank.
Important Considerations:
* Safety First: Fuel is flammable. Be cautious when working around the fuel system. Avoid sparks and open flames. Work in a well-ventilated area. Always disconnect the negative battery cable before working on the fuel system.
* Repair Manual: A repair manual specific to your 1988 Pontiac 6000 is invaluable. It will provide diagrams, specifications, and step-by-step instructions.
* Professional Help: If you're not comfortable performing these checks yourself, take your car to a qualified mechanic. Diagnosing fuel pump issues can be complex, and incorrect procedures can be dangerous.
The listening test and the fuel pressure test are the most reliable ways to determine if the fuel pump itself is malfunctioning. The other methods help rule out other potential causes of a no-start condition. Remember to always consult your vehicle's repair manual for specific instructions and safety precautions.
