Fuel Injector: Description and Operation

Fuel Injector Typical:

FUNCTION
The fuel injectors are solenoid operated valves that deliver fuel, in a metered amount, to the combustion chambers of individual cylinders.


OPERATION
When the solenoid coil is energized (on), the plunger is retracted lifting the needle valve off its seat, allowing fuel to be injected into the combustion chamber. When the solenoid is de-energized (off) spring pressure closes the valve.

This vehicle uses bottom fed fuel injectors. The bottom of the injector is fed with fuel from a passage in the intake manifold.

The ASD relay supplies voltage to the fuel injectors. The PCM controls the ground paths to fuel injectors, by switching the ground path on and off. The PCM can fine tune fuel delivery adjusting injector pulse width (on time).

CIRCUIT OPERATION
Circuit A14 is connected to the BUS bar in the Power Distribution Center (PDC), and connects to battery voltage. The contact side of the Automatic Shut-Down (ASD) relay connects circuits A14 and A142. A 20 Amp fuse, in cavity B of the PDC, protects circuits A14 and A142.

The Powertrain Control Module (PCM) controls the ground path for the coil side of the ASD relay on circuit K51. Circuit K51 connects to cavity 51 of the PCM.

Circuit A142 supplies voltage for the fuel injectors. The PCM controls the ground circuit of each injector, as follows:
- Circuit K11 is the ground circuit for Injector #1. Circuit K11 connects to cavity 16 of the PCM.
- Circuit K12 is the ground circuit for Injector #2. Circuit K12 connects to cavity 15 of the PCM.
- Circuit K13 is the ground circuit for Injector #3. Circuit K13 connects to cavity 14 of the PCM.
- Circuit K14 is the ground circuit for Injector #4. Circuit K14 connects to cavity 13 of the PCM.
- Circuit K38 is the ground circuit for Injector #5. Circuit K38 connects to cavity 5 of the PCM.
- Circuit K58 is the ground circuit for Injector #6. Circuit K58 connects to cavity 58 of the PCM.