Fuel Injectors

Four fuel injectors are located through a hole in the camshaft carrier. Each injector is sealed by a seat in the cylinder head and held in position by a clamp which is secured to the camshaft carrier with a bolt which passes through the carrier into the cylinder head.

Each injector is supplied with pressurized fuel from the fuel rail and delivers finely atomized fuel directly into the combustion chambers. Each injector is individually controlled by the PCM which operates each injector in the firing order and controls the injector opening period via Pulse Width Modulation (PWM) signals. Each injector receives a 12 V supply from the PCM and, using programmed injection/timing maps and sensor signals, determines the precise pilot and main injector timing for each cylinder. If battery voltage falls to between 6 V and 9 V, fuel injector operation is restricted, affecting emissions, engine speed range and idle speed.

The PCM can monitor the injector operation by monitoring both connections to the injector. Each injector can be diagnosed by the PCM and DTC stored. The codes can be retrieved using an approved diagnostic system.

If a fuel injector fails, the engine will suffer from unstable idle speed, poor Noise, Vibration and Harshness (NVH) and poor emissions performance. The engine Malfunction Indicator Lamp (MIL) in the IC will also be illuminated.

In the event of a failure of a fuel injector, the following symptoms may be observed:

• Engine misfire
• Idle irregular
• Reduced engine performance
• Reduced fuel economy
• Difficult starting
• Increased smoke emissions.