Obvious Signs (pointing strongly to a fuel pump issue):
* Engine cranks but won't start: This is a classic symptom. The engine turns over, but it won't catch and run because it's not receiving fuel.
* Engine sputters or hesitates, especially under acceleration: A weak pump can't supply enough fuel to meet the engine's demands. This is often worse when the tank is low.
* Loss of power: Similar to sputtering, the engine might feel sluggish or lack power, particularly uphill or when accelerating.
* Loud humming or whining noise from the fuel tank: This is the pump itself struggling. You might only hear this when the ignition is first turned on (before the engine starts). If the noise is consistent while driving, it could indicate a different problem.
Less Obvious Signs (require more investigation to rule out other causes):
* Engine cuts out intermittently: The car might suddenly stall, then restart after a short period. This could be related to a weak pump that intermittently fails to supply sufficient fuel.
* Hard starting, especially when hot: A hot engine might struggle to start because a failing pump is less efficient at higher temperatures. The fuel might be vaporizing more readily.
* Reduced fuel economy: A less efficient pump might not be able to deliver fuel consistently, resulting in slightly reduced gas mileage. This is a less reliable indicator on its own, however.
Important Considerations:
* Fuel filter: A clogged fuel filter can mimic fuel pump symptoms. It's always a good idea to replace the fuel filter before suspecting the fuel pump. A clogged filter adds pressure to the pump and will make it work harder and fail sooner.
* Other electrical issues: Problems in the fuel pump relay or wiring harness can cause similar issues. A mechanic can test the circuit to make sure it's working correctly.
* Fuel pressure test: This is the definitive way to diagnose a faulty fuel pump. A mechanic can measure the fuel pressure delivered by the pump to determine if it's within the manufacturer's specifications.
In short: If your car is struggling to start, has noticeable power loss, or makes unusual noises from the fuel tank area, a failing fuel pump should be suspected. However, a proper diagnosis requires a mechanic to perform the necessary tests to rule out other potential issues. Don't attempt to work on the fuel system yourself unless you have significant mechanical experience, as it involves working with highly flammable fuel.
