How to Repair Fuel Injectors

Updated February 21, 2017

Fuel injectors are used to mix the fuel in a car's engine with air, allowing the engine to run more smoothly at higher and lower temperatures. However, both the fuel pump and the fuel injector can become clogged, causing them to malfunction. Fortunately, there are a few cheap techniques that can be used to fix a fuel injector before car owners are forced to run out and purchase a new fuel injector.

Determine whether or not the problem stems from the fuel injector or the fuel pump. If the fuel pump is running slow or not running at all, check the power supply. Measure the pressure emitted from the pump by attaching a static output pressure gauge to the fuel rail. Check if the pressure read by the static output pressure gauge is releasing the pressure that the fuel pump manual recommends.

Check the fuel injector filter. These filters often become clogged. Clogged filters can be replaced at a much lower cost than replacing the entire injector. Clogged fuel injectors and fuel injector filters are the most common problems that cause a fuel injector to not work properly.

Place the tip of a thin metal rod on the malfunctioning fuel injector.

With a hammer, gently tap the other end of the metal rod. Be sure to tap on the fuel injector when the engine is running. If the injector still doesn't work, tap slightly harder.

Consider getting a replacement. If you cannot get the fuel injector to work, it is likely shot.


Fuel injectors are potentially fire and eye hazards. Wear eye protection and keep a fire extinguisher at hand. Do not tap on the fuel injector so hard that you puncture it.

Things You'll Need

  • Static output pressure gauge
  • Hammer
  • Metal rod extension
Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Charles Pearson has written as a freelancer since 2009. He has a B.S. in literature from Purdue University Calumet and is currently working on his M.A. He has written the ebooks "Karate You Can Teach Your Kids," "Macadamia Growing Handout" and "The Raw Food Diet."