1. Listen for the hum:
* Turn the ignition key to the "ON" position (without starting the engine). You should hear a brief humming sound from the fuel pump in the fuel tank. This sound usually lasts for a couple of seconds. It's a quiet hum, so you might need to listen carefully. If you don't hear anything, the pump *might* be faulty, but there are other possibilities (blown fuse, faulty relay, etc.).
2. Check fuel pressure:
* This is the most definitive test. You'll need a fuel pressure gauge and a fitting that connects to your fuel rail (a specialized fitting may be required, usually obtained from an auto parts store). Consult your repair manual for the correct pressure specifications for your engine. With the engine OFF, connect the gauge. Then, crank the engine (don't run it for long). The gauge will show the fuel pressure. If the pressure is significantly below the specification, the fuel pump is likely the culprit, though other components in the fuel delivery system could also be at fault. CAUTION: Gasoline is extremely flammable. Be extremely careful when working with fuel systems. Only perform this test in a well-ventilated area, away from any ignition sources.
3. Check the fuel pump relay:
* A faulty relay can prevent power from reaching the fuel pump. Locate the fuel pump relay (consult your owner's manual or a repair manual for its location). You can test the relay with a multimeter or by swapping it with a known good relay of the same type (again, this requires referring to your repair manual for the correct relay).
4. Check the fuel pump fuse:
* Similar to the relay, a blown fuse will interrupt power to the fuel pump. Locate the fuel pump fuse in the fuse box (check your owner's manual) and visually inspect it for a blown element (broken filament). A multimeter can also confirm if the fuse is blown.
5. Observe fuel delivery (less reliable):
* If the engine cranks but doesn't start, and you've ruled out other obvious issues (spark, air intake), lack of fuel delivery points towards a fuel pump problem. However, this isn't definitive proof as other fuel system components could be the problem.
Important Considerations:
* Safety First: Working with gasoline is dangerous. Always follow proper safety precautions when dealing with fuel systems.
* Repair Manual: A repair manual specific to your 1999 Oldsmobile Aurora is invaluable for locating components, understanding fuel system specifications, and troubleshooting procedures.
* Professional Help: If you're not comfortable performing these checks, take your vehicle to a qualified mechanic. Diagnosing fuel system problems can be complex, and incorrect procedures could lead to further damage or injury.
The hum test is a quick initial check, but the fuel pressure test is the most reliable way to determine if your fuel pump is working correctly. If the fuel pressure is low, you will need to investigate further to determine if the pump itself is the problem, or if there's another fault in the fuel system.
