Fuel Injector: Description and Operation

MPFI Injector Assembly:

PCM Wiring:

PURPOSE
The Port Fuel Injector is a solenoid-operated device, controlled by the Powertrain Control Module (PCM), that meters the pressurized fuel to a single engine cylinder.

OPERATION
The PCM energizes the solenoid to open a normally closed injector pintle. The position of the injector in the intake manifold directs the fuel spray at the back side of the intake valve. The fuel is further atomized before entering the cylinder combustion chamber.

DIAGNOSTIC NOTES
An injector that is stuck partly open would cause loss of pressure after engine shut down, so long crank times would be noticed on some engines. Dieseling could also occur because some fuel could be delivered to the engine after the ignition is turned "OFF."