Beretta V6-173 2.8L (1989)
Fuel Injector: Description and Operation
MPFI Injector Assembly
MPFI Injector - Cross Section
The Multi-Port Fuel Injector is a solenoid-operated device, controlled by the Electronic Control Module (ECM), that meters the pressurized fuel to a
single engine cylinder. The ECM energizes the low impedance (8.0 Ohms) solenoid to open a normally closed ball valve. This allows the fuel to flow
into the top of the injector, past the ball valve, and through a recessed flow director plate at the injector outlet. The director plate has six machined holes
that control the fuel flow, generating a conical spray pattern of finely atomized fuel at the injector tip. Fuel from the tip is directed at the intake valve,
causing it to become further atomized and vaporized before entering the combustion chamber.
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."
