Fuel Injectors
Four fuel injectors are located through a hole in the camshaft carrier. Each fuel 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. The bolt passes through the camshaft carrier into the cylinder head.
Each fuel injector is supplied with pressurized fuel from the fuel rail and delivers finely atomized fuel directly into the combustion chambers. Each fuel injector is individually controlled by the Powertrain Control Module (PCM). The PCM operates each fuel injector in the firing order and controls the fuel injector opening period via Pulse Width Modulation (PWM) signals.
Each fuel injector receives a 12V supply from the PCM. Using programmed injection/timing maps and sensor signals, the PCM determines the precise pilot and main injector timing for each cylinder. If the startup battery voltage falls to between 6 and 9V, fuel injector operation is restricted, affecting emissions, engine speed range and idle speed.
The PCM can monitor the fuel injector operation by monitoring both connections to the fuel injector. Each fuel injector can be diagnosed by the PCM and Diagnostic Trouble Codes (DTC) stored. The codes can be retrieved using an approved diagnostic equipment.
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 Instrument Cluster (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.