Fuel Injectors
The fuel injectors spray fuel from the fuel rail directly into the combustion chambers. The fuel injectors are installed close to the center of the combustion chambers, between the inlet and exhaust valves and next to the spark plug.
The fuel injectors are a push fit in the fuel rails and the cylinder heads. On each fuel injector an O-ring seal and support disc seals the head of the fuel injector in the fuel rail. A Teflon combustion seal ring seals the nozzle of the fuel injector in the cylinder head.
Each fuel injector contains a solenoid-operated needle valve, which opens when the solenoid winding is energized. While the needle valve is open, fuel is sprayed into the combustion chamber. There are six holes around the tip of the nozzle through which the fuel is sprayed. Two of the holes direct fuel below the spark plug. The other four holes direct fuel evenly around the remainder of the combustion chamber.
The solenoid winding is connected to a power feed and a ground from the Powertrain Control Module (PCM), which operates the fuel injectors with a two stage power supply. Initially the PCM supplies the fuel injectors with 65 V, then once the boost current reaches 11.5 A the power supply is switched to battery voltage. When the fuel injector is opened, the PCM controls the current flow at approximately 3.1 A. The PCM meters the amount of fuel injected into the combustion chambers by adjusting the time that the solenoid winding is energized.
If a fuel injector fails, the engine will suffer from unstable idle speed, poor Noise, Vibration and Harshness (NVH) and poor emissions performance. The Malfunction Indicator Lamp (MIL) in the Instrument Cluster (IC) will also be illuminated.