If your car won't start, or if it starts, sputters and stops, then the cause of the problem may be a defective fuel pump. Your car's fuel pump is the heart of the vehicle, and if it fails to function properly, your car will go nowhere. However, sitting in the driver's seat, it can be difficult to know with certainty if a faulty fuel pump is the cause of your car's problem. That is why it is important to take a few moments to perform a listening assessment of the fuel pump's operation. Below are a few ways you can use your ears to help you determine if your fuel pump is operational:
Listen for fuel flowing into the engine
One of the easiest tests to perform is to listen for the sound of fuel flowing into the engine from the tank. To perform this listening test, you will need the assistance of a helper to turn the ignition key on and off. Begin by ensuring that all noise-making accessories, such as the air conditioner and audio system, are turned off, and try to eliminate as much background noise as possible. Next, raise the hood, and locate the fuel line emerging from the back of the engine compartment. The fuel line will be a rubber hose that terminates in a filter and/or pressure sensor.
After locating the line, position your ear as close as safely possible to it and give a predetermined signal to your helper to turn the ignition key to the 'ON' position.
If the fuel pump is functioning, you will hear the sound of fuel flowing through the line and into the fuel pressure sensor and filter. This sound will last briefly--only a second or two--then it will become silent again. If you aren't certain and need to listen again, ask your helper to turn the key to the 'OFF' position, then back to 'ON' position.
Listen for the fuel pump to engage
Another listening test that is helpful to some individuals, especially those uncomfortable with placing their heads into the area above the engine compartment or those with limited hearing, is to listen for the fuel pump itself as it engages. Since electronic fuel pumps are located within the gasoline tank, this listening test will be performed at the fuel filler opening. Begin by checking to see if all noise-making accessories are silenced, and ask a helper to sit in the driver's seat ready to turn the ignition key. Next, remove the fuel filler cap on your vehicle, and position your ear just outside this opening. Be careful not to inhale gas fumes, and do not linger in the vicinity longer than necessary.
At this point, indicate to your helper that you are ready to turn the ignition to the 'ON' position. If you hear a whirring sound that ceases after a couple of seconds, then you can feel comfortable knowing the fuel pump is operational. Be sure to allow your assistant to turn the ignition to 'ON' at least two to three additional times to check for consistency of operation.
Should you still be unable to hear the fuel pump, then the next step is to move your ear closer to the pump by positioning yourself underneath the vehicle and fuel tank. Before lowering oneself beneath a vehicle, be sure the wheels are chocked and the parking brake is firmly engaged. Next, turn your ear toward the fuel tank, and give the signal to turn the ignition to 'ON'; if the fuel pump is working, you will hear the sound of a relay engaging and the whirring of a pump for a few seconds. Should you hear nothing, sharply rap the bottom of the fuel tank several times using a flat tool such as a screwdriver. The fuel pump is located at the bottom of the tank, and the sharp blows can occasionally "jump start" the pump. Continue to ask the helper to turn the ignition 'ON' and 'OFF' if necessary, to listen again for functioning.
If you still can't hear the fuel pump, then it's likely in need of repairs. You can visit sites like http://www.soundsideauto.com to learn about auto repair shops in your area that you can take your car to.