Cherokee 2WD L6-4.0L VIN S (1998)
Fuel Injector: Description and Operation
Fuel Injector - Typical
The fuel injectors are electrical solenoids. The injector contains a pintle that closes off an orifice at the nozzle end. when electric current is supplied to
the injector, the armature and needle move a short distance against a spring, allowing fuel to flow out the orifice. Because the fuel is under high pressure,
a fine spray is developed in the shape of a pencil stream. The spraying action atomizes the fuel. adding it to the air entering the combustion chamber.
An individual fuel injector is used for each individual cylinder. The top (fuel entry) end of the injector is attached into an opening on the fuel rail
The nozzle (outlet) ends of the injectors are positioned into openings in the intake manifold just above the intake valve ports of the cylinder head. The
engine wiring harness connector for each fuel injector is equipped with an attached numerical tag (INJ 1, INJ 2 etc.). This is used to identify each fuel
injector.
The injectors are energized individually in a sequential order by the powertrain control module (PCM). The PCM will adjust injector pulse width by
switching the ground path to each individual injector
on and off. Injector pulse width is the period of time that the injector is energized. The PCM will adjust injector pulse width based on various inputs it
receives.
During start up battery voltage is supplied to the injectors through the ASD relay. When the engine is operating, voltage is supplied by the charging
system. The PCM determines injector pulse width based on various inputs.
