Obvious Signs (Strong Indicators):
* Engine cranks but won't start: This is a classic symptom of a failing fuel pump. If the engine cranks but doesn't fire, the fuel pump may not be delivering fuel to the engine.
* Whining noise from the fuel tank: Listen carefully while someone cranks the engine. A whining or buzzing sound coming from the fuel tank area is a strong indication of a failing fuel pump. This sound is often more pronounced when the tank is low on fuel.
* Hesitation or sputtering: The engine may hesitate or sputter, especially under acceleration, indicating inconsistent fuel delivery.
* Reduced fuel pressure: This requires a fuel pressure gauge to measure. If the fuel pressure is below the manufacturer's specifications, it points towards a faulty fuel pump. This is the most definitive test.
Less Obvious Signs (Could indicate other problems):
* Poor fuel economy: While not exclusive to a failing fuel pump, a sudden and significant drop in fuel efficiency could be a sign.
* Engine surges or stalls: Inconsistent fuel delivery can cause the engine to surge or stall unexpectedly.
* Weak fuel smell: A strong fuel smell may suggest a leak in the fuel system, which could be related to a failing pump or other component.
How to proceed:
1. Check the fuel level: Make sure you actually have fuel in the tank. Sounds obvious, but a low fuel level can sometimes mimic fuel pump problems.
2. Listen for the fuel pump: Turn the ignition key to the "ON" position (don't start the engine). You should hear a brief hum from the fuel tank area. If you don't hear anything, the pump may be faulty or the pump relay might be bad.
3. Check fuel pressure (most definitive): This requires a fuel pressure gauge and some mechanical aptitude. You'll need to connect the gauge to the fuel rail and check the pressure while the engine is running. The correct pressure specification can be found in your owner's manual or a repair manual. A low reading indicates a problem with the fuel delivery system, possibly the pump.
4. Professional Diagnosis: If you're not comfortable performing these checks yourself, take your Focus to a qualified mechanic. They have the tools and expertise to properly diagnose the issue and determine if the fuel pump needs replacement or if another component is at fault.
Don't delay addressing a suspected fuel pump problem. Driving with a failing fuel pump can lead to complete engine failure, leaving you stranded.
