How to Rebuild a Fuel Injector

If you are having fuel delivery issues with your car, the following article will help you rebuild fuel injectors. The fuel injection system in your car is the way your car mixes the fuel and air in the engine's cylinder heads. The fuel injectors forcibly push the fuel into the cylinder heads in a powerful mist. The air intake system supplies the air into the cylinder heads and the combination of the fuel and air creates the ingredients for the powerful explosion in the engine block that supplies the necessary force to power the engine. Here are some instructions to rebuild a fuel injector.

Tools and Materials Needed:

  • Fuel-injector repair kit (be sure it has enough parts for all your injectors)
  • Safety goggles
  • Carburator cleaner
  • Metal bucket or container
  • Socket wrench and sockets
  • Pliers
  • Can of compressed air
  • Shop rags
  • Rubber gloves

Step 1 – Preparation

Be sure to wear your safety goggles when working around the fuel system and to rebuild a fuel injector. Open your car's hood and disconnect the negative battery cable from the battery. Place the cable end where it will not touch any metal or get in your way. The fuel injectors are located under the fuel rails. Locate the fuel rails and remove the bolts securing them to the engine block. Set the fuel rails off to the side and out of the way.

Step 2 – Removing the Fuel Injectors

Each cylinder has its own fuel injector, so an 8-cylinder engine will have 8 fuel injectors to rebuild. Disconnect the wired connector leading to the injector before removing them. Remove each injector by pulling straight up on the injector without rocking it back and forth. Fuel injectors are delicate and can be easily damaged or broken. Be sure nothing drops into the empty injector holes during this rebuild process.

Step 3 – Disassembling and Cleaning the Fuel Injectors

There are only a few parts to remove on an injector; the filter and pintal cap. The filter sits at the top part of the injector and the pintal cap sits at the bottom part. Remove all the filters and pintal caps using your pliers, being careful not to damage the injector in the process. You will not need to save anything besides the actual injector. Take the fuel injectors and soak them in a container of brake cleaner overnight. Brake fluid is very caustic so do not allow it to contact your skin or any painted surface.

Step 4 – Rebuild Your Fuel Injectors

Remove the fuel injectors from the cleaning fluid and thoroughly wipe off any fluid from the surface. Take the can of compressed air and insert the tube into the bottom of the injector and blow out any debris in the injector. Repeat this for all your fuel injectors. Wipe the injector dry before moving on to the next step. Reassemble each injector using the parts from the fuel-injector repair kit.

Step 5 – Rebuild the Fuel Injectors

Put an O-ring at the top and bottom of each fuel injector and securely push each injector into the fuel injector hole in the engine block. Push the injector firmly straight down into the hole without damaging it.

Reconnect the wired connector to the injector and the fuel rails. Secure the rails tightly so no fuel leaks out later. Thoroughly wipe away any excess fuel or brake cleaner fluid that you may have missed earlier and then reconnect the negative battery cable.

Start the engine and inspect for any leaks. Close the hood and properly and carefully dispose of the used brake cleaning fluid used to rebuild a fuel injector.