How to Prime an Electric Fuel Pump

fuel pump in an engine
What You'll Need
Manufacturer's directions
What You'll Need
Manufacturer's directions

An electric fuel pump is an essential component that can be found in your car. The fuel pump is used to make sure the gas travels from the fuel tank to the engine. The fuel must travel through a hose, also called the fuel line, and it is the job of the fuel pump to make sure the gas reaches the proper location. The fuel pump is used in any car where gravity cannot be used to pump the fuel into the system. There are two types of engines. The first is known as a carbureted engine and the other is known as a fuel injected engine. The fuel injected engine in most cases will use an electric fuel pump. You may need to prime it to boost the gas flowing through the system. Below are instructions on how to prime the electric fuel pump.

Step 1 - Find the Fuel Pump

Make sure the car is off and make sure it has been sitting for at least a couple hours. You will be working around the fuel injection components of your car and you can easily get burnt if the car is still warm. Put on protective gloves before you work inside and around the car. You may need to lift the car up to access it from underneath. In many models you will need to drain and pull the gas tank. In some models the fuel pump is easy to access under the back seat or through floor of trunk. If you are not sure where the fuel tank is, then pull out your manufacturer's directions. Once you have located the fuel tank, locate the electric fuel pump. The pump is usually located inside the tank.

Step 2 - Flip the Switch

fuel pump plug

There should be a prime switch located on the fuel pump line. Flip the switch to prime the fuel pump. You can prime the fuel pump a couple of times but do not leave it in the "on" position.

Step 3 - Close the Hood and Clean Up

Close the hood of the car and clean up your work area. Clean your hands completely with a cleaning agent that will remove any remnants of the fuel on your hands.

Step 4 - Test the Car

Test out the car. Re-prime the electric fuel pump if necessary.

A Few Notes:

  • This is generally something you will want to do when you want to bleed your line. For normal automobile operation, you will not need to prime your electric fuel pump.
  • A prime switch is also used for safety reasons. You can use the prime switch when your engine may seem to start to die or when the filters in the car become clogged.
  • Some models of electric fuel pumps do not need to be primed by hand as they have a self priming feature built in. Be sure to check the information located in the manufacturer's book of information to find out what type of priming system your car has.
  • If you are unsure, consult the help of a certified automotive mechanic to prime your electric fuel pump.