How to Clean Clogged Fuel Injectors

Updated February 21, 2017

The automobile fuel injector mixes gasoline with air to create optimal engine performance. It is a standard feature on today's automobile, replacing the less efficient carburettor back in the late 1980s. Over time, gas vapours solidify on the surface of the injector. This build-up can clog the injector and create inefficiency in an automobile's operation. Signs of a clogged fuel injector include engine knocking and sluggishness. There are several steps you can take to remove this build-up and keep your fuel injectors running clean and smooth.

Use a high quality gasoline grade in your automobile. This might be a bit more expensive, but it has additives that help keep your injector clean.

Put a fuel injector cleaner directly into your gas tank.

Drive your automobile as you normally would. The cleaner additive will help remove build-up on your injector.

Read fuel injector cleaning kit thoroughly before starting process.

Disengage the fuel pump and plug up the fuel return line or install a U-tube to the fuel pump. This will cause the fuel to be returned to the fuel tank.

Detach the pressure regulator and hook the cleaning kit to the port on the fuel rail.

Unscrew the gas cap. This will reduce the chance of excess pressure building up within the fuel system.

Ensure that the fuel pump is turned off. This can be determined by attempting to turn on the ignition. If the pump is off, the car will not start.

Refer to your car owner's manual to determine the appropriate fuel pressure reading for your automobile.

Open the valve on the fuel injector cleaner kit until the you reach the proper fuel pressure reading for your car.

Turn on the engine and allow it to run about five minutes or until the solvent container is empty. At this point your engine will shut down.

Set the fuel pump switch back to its normal operating position and screw on the gas cap.

Uninstall the injector cleaner kit and reattach the pressure regulator.

Reattach your fuel pump and unplug the fuel return line, or remove the U-tube.

Turn on the engine. Place a long screwdriver on the fuel injectors. Put the handle up to your ear and listen for rapid clicking sounds. This indicates your injectors are in proper working order.


The solvent in the fuel injector cleaning kit can eat away at petroleum-based components in your car such as tires and belts. The solvent is highly flammable. Never smoke or have an open flame present during this procedure.

Things You'll Need

  • Quality grade gasoline
  • Fuel injector cleaner
  • Fuel injector cleaning kit
  • 12-inch screwdriver
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About the Author

Shelly Schumacher has a diverse writing background that includes work in print as well as electronic publications. She has been writing for over 18 years and enjoys working with a variety of different clients on both writing projects and as a marketing and public relations consultant. Schumacher holds a Bachelor of Science in journalism from the University of Wisconsin.