1. Listen for the Fuel Pump Prime:
* Turn the ignition key to the "ON" position (without starting the engine). You should hear a brief humming or whirring sound from the fuel pump. This sound typically lasts for a few seconds. If you don't hear it, the pump might be faulty, or there might be a problem with the pump relay or fuse.
This is the easiest and quickest check. If you hear the pump prime, it's *likely* working, but doesn't guarantee it's functioning perfectly under pressure.
2. Check Fuel Pressure:
* This requires a fuel pressure gauge. This gauge connects to the fuel system's test port (location varies by vehicle). Your vehicle's repair manual will show you where to connect it.
* Turn the ignition key to the "ON" position. The gauge should show the fuel pressure specified in your vehicle's manual. Low pressure or no pressure indicates a potential fuel pump problem.
* Start the engine. The pressure should remain stable within the specified range. Fluctuations or a drop in pressure while running also suggest a problem.
This is a more accurate test than just listening for the prime. It confirms the pump is delivering the correct pressure.
3. Inspect the Fuel Pump Relay and Fuse:
* Locate the fuel pump relay and fuse in the fuse box (usually under the hood or inside the cabin). Your vehicle's manual will show their locations.
* Visually inspect the fuse for a blown element (a broken filament). Replace it if necessary with a fuse of the same rating.
* Check the relay. You can often swap it with a similar relay to see if it resolves the issue. (Some vehicles have a fuel pump relay and a fuel pump control module which may need to be tested in addition).
This step rules out simple electrical issues.
4. Visual Inspection (Advanced - Requires Fuel System Knowledge):
* This requires disconnecting fuel lines and potentially dropping the fuel tank (often requiring specialized tools and knowledge). Do not attempt this unless you have experience working on fuel systems and are comfortable with the associated safety hazards.
* Inspect the fuel pump for physical damage.
* Inspect the fuel pump filter (sometimes located within the pump assembly or separately in the fuel line). A clogged filter can restrict fuel flow.
This is a very advanced step and should only be performed by experienced mechanics. Incorrectly handling fuel systems can be extremely dangerous.
Important Safety Precautions:
* Always disconnect the negative battery terminal before working on any part of the fuel system.
* Fuel is flammable and potentially explosive. Work in a well-ventilated area, away from open flames and sparks.
* Use proper safety glasses and gloves.
* If you're not comfortable performing these checks yourself, take your vehicle to a qualified mechanic.
If you are unsure about any step, consult a professional mechanic. Improperly handling fuel system components can be dangerous.
