Wagoneer L4-150 2.5L VIN E TBI (1990)
Fuel Injector: Description and Operation
Throttle Body And Injector
The fuel injector is a solenoid operated valve that delivers fuel, in a metered amount, into the throttle body where it gets distributed to the intake
manifold and out to the individual cylinders. When the solenoid coil is energized, the plunger is retracted lifting the needle valve off its seat, allowing
fuel to be injected into the throttle body. When the solenoid is de-energized spring pressure closes the valve.
Since the injection nozzle opening is a fixed size and the fuel pressure is also fixed (14.5 psi), the amount of fuel that is injected is determined by the
amount of time that the needle valve remains open. This time is commonly referred to as the "pulse width" of the injector. The engine Control Unit
(ECU) controls the pulse width of the injector to change the air/fuel ratio for varying engine driveability conditions.
