Electric and Mechanical Fuel Pumps
On fuel injection cars and trucks, the electric fuel pump is located at the rear of the car or truck and may be in the fuel tank or located along the frame rail close to the fuel tank. Most electric fuel pumps will fail without warning, however if you start to hear your fuel pump making a loud humming noise that you can hear over the noise of the engine it may be time to replace the fuel pump.
The primary way fuel pumps fail is by running your car or truck out of gas. Since the fuel is used to lubricate the fuel pump, running the car out of gas will burn up the fuel pump very quickly. For those who have to replace the pump, and you have an electric fuel pump that is located in the fuel tank, you will need to try to find the access panel under the seat or in the trunk. (Some vehicle require you to remove the fuel tank) Once removed you will be able to see the fuel lines and the top of the fuel-sending unit.
You should be able to remove the entire fuel pump and sending unit from the top of the tank. For vehicles equipped with an electric fuel pump outside the tank, be careful removing the fuel lines as they are under pressure. Wear eye protection! Mechanical fuel pumps are typically driven from the front of the timing chain, and use a vacuum system that siphons fuel from the fuel tank and then under pressure delivers it to the carburetor. These fuel pumps have a diaphragm in them that is the weak point and is typically the part that fails.
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