How to Listening for Bad Fuel Injectors

How to Listening for Bad Fuel Injectors?

1. Put on the appropriate safety gear. Before beginning any automotive project, you need to take steps to protect yourself from injury. Eye protection like safety glasses or goggles will keep debris from falling or spraying into your eyes while you work. Choose eye protection that fits comfortably and won't interfere with your vision. Gloves are an optional addition to the safety gear required for this task.
  • Gloves can protect your hands from sharp objects or pinches while working in the engine bay.
  • Eye protection is required for this project.


2. Open the hood and locate your fuel injectors. The easiest way to locate the fuel injectors for your specific vehicle is to refer to the service manual for that vehicle. Most applications have one fuel injector for each cylinder. They are usually located on the intake manifold and are connected to one another with a fuel rail.

  • The fuel rail is a cylindrical rail that will run along the top of the intake manifold, and each fuel injector will be between the fuel rail and the intake manifold.
  • V style engines (V6, V8, V10) will have two fuel rails with half of the injectors on each side of the motor.

3. Find a long metal rod or screwdriver. Locate a thin piece of metal that’s at least a foot or so long. It should be made mostly of metal, but you could opt to use a screwdriver despite it having a plastic or rubber handle.
  • Make sure the piece you choose is at least a foot long, but not more than two feet.
  • A long screwdriver or thin piece of rebar will work fine.

4. Place the tip of the rod on a fuel injector. You will be using the metal rod to transmit sound from the fuel injector to your ear without having to bring your face too close to a running engine. Set one end of the rod or screwdriver on the injector itself while holding it up with one hand.
  • Make sure to hold the screwdriver or metal rod at an angle that will allow you to bring your ear to it.

5. Bring your ear close to the rod and listen for clicking. Lean your ear close to the end of the metal rod or screwdriver that is opposite the injector. As the engine runs, listen for an audible clicking sound given off by the injector. This sound indicates the injector being activated.
  • Be extremely careful leaning your head into the engine bay, and ensure you keep your eyes open as you listen to the rod to prevent accidentally getting injured.
  • If you have long hair, tie it back tightly to prevent it from getting caught in any moving parts under the hood.

6. Repeat these steps for each injector. Use the same method to check each fuel injector in your vehicle. If you find one that is not clicking, there is an issue with the injector or the electronic control that is transmitting to the injector.
  • If you have an OBDII scanner and your vehicle’s check engine light is on, you can check to see if there have been any errors in the vehicle’s computer regarding that cylinder or injector.
  • Replacing this injector may solve the problem, but you may also need to have a diagnostic done of your vehicle’s electronic control unit and fuel system by a professional mechanic.
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