How to Pressurize a Car's Fuel System

by Cayden Conor

After you have completed a repair such as changing the fuel pump or changing the fuel filter you will have to re-pressurize the car's fuel system. If you have just diagnosed a no-start by releasing the schrader valve in the fuel line, you may also have to re-pressurize the fuel system.

How to Pressurize a Car's Fuel System

To save wear and tear on your starter, pressurize your car's fuel system before attempting to start your car. Fuel injected cars have between 32 to 60 pounds of fuel pressure in the lines, depending on what year, make and model car you are working on. You would have had to de-pressurize the fuel system to work on the filter, pump or fuel lines. Make sure your repair is complete, and all nuts and bolts are in their proper place and tightened to the correct torque specs. If you replaced your fuel pump, make sure it is seated in the tank properly, and the wiring is hooked up properly.

Turn the key to the on position for approximately two seconds. You may be able to hear the fuel pump buzzing, then stop. As a safety precaution, if you do not start the car, the fuel pump will turn itself off. After two seconds, or if you can hear the pump, after it shuts itself off, turn the key off for approximately five seconds. Repeat this procedure at least three times. Your fuel system should be pressurized. You may now attempt to start the car.

If you are working on a carburated system with a manual fuel pump the above procedure will not work. Hopefully, you will have some fuel left in the carb bowl, and this should be enough to keep the car running until the system is pressurized again. If you just put a new or rebuilt carb on, the fuel bowls will be empty. You will have to crank over the engine a few times to fill the fuel bowls.

Tips

  • check Make sure your fuel pump is hooked up correctly, if you used the disconnect method. If you cannot hear your fuel pump buzz, have someone open the fuel door and listen when you turn the key on.
  • check Remember, the fuel pump will only come on for approximately two seconds with the key in the on position, and shut itself off if you do not attempt to turn the car over.

Items you will need

About the Author

Cayden Conor has been writing since 1996. She has been published on several websites and in the winter 1996 issue of "QECE." Conor specializes in home and garden, dogs, legal, automotive and business subjects, with years of hands-on experience in these areas. She has an Associate of Science (paralegal) from Manchester Community College and studied computer science, criminology and education at University of Tampa.