How to Replace a Car Fuel Injector
Car 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 anengine cylinder misfire. To replace a failed fuel injector follow the steps below.
Car Fuel Injector diagram
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 totest 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.
Fuel injector piston & valves