Performance Issues:
* Engine cranks but won't start: This is a classic symptom. If the pump isn't supplying fuel, the engine can't ignite.
* Hesitation or sputtering: The engine might struggle to accelerate smoothly or sputter under load, indicating inconsistent fuel delivery.
* Loss of power: Similar to sputtering, the engine might feel weak or lack power, especially at higher RPMs.
* Stalling: The engine might stall unexpectedly, especially after prolonged periods of idling or driving.
* Difficulty starting after sitting: The pump might take longer to prime and deliver fuel after the engine has been sitting for a while.
Audible Clues:
* Whining or buzzing noise: You might hear a high-pitched whine or buzzing sound coming from the fuel tank area, especially when the ignition is first turned on. This is the pump trying to operate but failing effectively. A loud, unusual noise, however, may also indicate a more serious mechanical failure.
* No initial pump prime noise: When you first turn the key to the "on" position (before cranking), you should hear a brief whirring sound from the fuel pump as it primes the system. If you don't hear this sound, it's a strong indicator of a failing pump.
Other Indicators:
* Fuel gauge inaccuracies: While not directly related to the pump's function, erratic fuel gauge readings can sometimes be associated with issues within the fuel system, including a failing pump.
* Check Engine Light: A illuminated check engine light might be accompanied by a diagnostic trouble code (DTC) related to fuel system problems. This will need to be scanned using an OBD-II reader to determine the specific issue.
* Smell of fuel: A strong smell of gasoline could indicate a fuel leak, which may be related to pump failure (though this could be from other fuel system components as well).
Important Note: Many of these symptoms can also be caused by other fuel system problems, such as a clogged fuel filter, bad fuel pressure regulator, faulty fuel injectors, or other issues within the fuel delivery system. Therefore, it is essential to have a proper diagnosis by a mechanic before replacing the fuel pump. Incorrect diagnosis and replacement of the wrong part can be costly.
