Fuel Injection - 3.6L: Notes
DESCRIPTION
The fuel injection system inputs are made up of the following:
| 1. | Refer to OXYGEN SENSOR . |
| 2. | Ignition Coil |
| 3. | Refer to INTAKE AIR TEMPERATURE (IAT) SENSOR . |
| 4. | Refer to THROTTLE BODY . |
| 5. | Refer to MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR . |
| 6. | Camshaft Position Sensor |
| 7. | Refer to POWERTRAIN CONTROL MODULE (PCM) . |
| - | Refer to CRANKSHAFT POSITION (CKP) SENSOR - not shown. |
| - | Refer to ACCELERATOR PEDAL POSITION SENSOR (APPS) - not shown. |
| - | Refer to FUEL INJECTORS - not shown. |
OPERATION
Various sensors provide the inputs necessary for the PCM to correctly operate. The PCM continuously adapts to meet changing operating conditions and driving demands.
Fuel is injected into the intake port above the intake valve in precise metered amounts through electrically operated fuel injectors. Under most operating conditions, the PCM maintains an air fuel ratio of 14.7 parts air to 1 part fuel by constantly adjusting injector pulse width. Injector pulse width is the length of time the injector is open. The PCM adjusts the injector pulse width by opening and closing the ground path to each injector. Upstream Oxygen sensor feedback is the main input to fueling. Throttle input, engine speed, and MAP sensor feedback are contributing factors.
In order to maintain a 14.7 to 1 air fuel ratio the PCM regulates:
- Ignition timing.
- Air/fuel ratio.
- Emission control devices.
- Cooling fan.
- Charging system.
- Idle speed.
- Vehicle speed control.
The PCM also monitors the Fuel Injector system wiring for and related electrical faults.