Mechanics

Fuel Injector Replacement

How to Replace a Fuel Injector

A fuel injector can be used to supply fuel to one or more cylinders. A multi-port fuel injection system or TBI (throttle body injection) uses two fuel injectors to feed six or eight cylinders and one injector to feed four cylinders. Direct port injection or DPI uses one fuel injector for each cylinder of the engine. Each of these fuel injector styles depend on a uniform spray pattern and a constant fuel pressure supply. When a fuel injector fails it can do so in many different ways. Among the most common are: pintel valve failure, magnetic coil short circuit and fully or partially plugged nozzle. Any of these failures will result in an engine cylinder misfire. To replace a failed fuel injector follow the steps below.

Please park your car on level ground and place the transmission in park with the emergency brake set. Also, we will be dealing with gas so please wear protective gloves, clothing and eyewear for safety.


Tools and Supplies to Complete this Job

1. Replacement fuel injector and "O" rings and gaskets if needed.

2. Shop Towels

3. Socket and Ratchet Set.

4. Wrench Set.

5. Screw Driver Set


Instructions

Step 1 - Find and actuate the hood release lever, release the secondary hood catch and raise the hood. Support with hood prop if needed.

Step 2 - Identify the failed fuel injector that will be targeted for replacement. If you do not know which fuel injector has failed here are instructions on how to test a fuel injector.

Step 3 - Remove any covers or intake manifold components to aid in the fuel injector removal.

Step 4 - Disconnect the electrical connector at the failed fuel injector.

Step 5 - If possible relieve any residual fuel pressure in the system by releasing the fuel pressure test port or by loosening a fuel line either at the fuel filter or fuel rail. Be ready with a shop towel to catch excess fuel.

Step 6 - Loosen and remove the fuel rail mounting bolts, then gently pry up on the fuel rail to "pop" it loose from the fuel injectors. Most fuel rails have injector retainer clips that secure the fuel injector to the fuel rail. This clip will need to be removed in order to replace the fuel injector.

Step 7 - Once the retainer clip has been removed gently pull the fuel injector from the fuel rail. (Note: The fuel injector is sealed to the intake manifold and fuel rail by "O" ring seals that will need to be replaced if damaged or worn.

Step 8 - Insert the new "O" seal onto the replacement fuel injector.

Step 9 - Install the replacement fuel injector into the fuel rail and re-install the retainer clip. (Note: A small amount of lube to aid the installation is sometimes needed).

Step 10 - Re-install the fuel rail onto the intake manifold by inserting the mounting bolts by hand. This will help to ensure a proper seal.

Step 11 - Once the fuel rail is securely in place continue to tighten the mounting bolts until snug.

Step 12 - Re-install the intake manifold components to complete the repair process.

Step 13 - Once the job is complete start the engine and check the fuel rail and injectors for leaks.

(Note: Occasionally it is necessary to remove the fuel lines from the fuel rail, it is best to leave the fuel lines connected to avoid fuel contamination when possible)


Best Practices

  • Always replace the fuel filter when replacing a fuel injector
  • Clean the throttle bore when changing a fuel injector
  • Always use new sealing "o" rings on the fuel rail
If further assistance is needed, our certified car repair technicians are ready to answer your car questions. Also, gain manufacturer specific instructions and information by clicking - Auto Repair Manual


Related Car Repair Information

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-08-16)