Grand Prix V6-191 3.1L VIN M SFI (1998)
Fuel Injector: Description and Operation
DESCRIPTION
The Sequential Multiport Fuel Injection (SFI) fuel injector is a solenoid (3) operated device controlled by the PCM
OPERATION
The PCM energizes the solenoid which opens a valve (1) to allow fuel delivery onto the director plate (2). The fuel is injected under pressure in a
conical spray pattern at the opening of the intake valve. Excess fuel not used by the injectors passes through the fuel pressure regulator before being
returned to the fuel tank. A fuel injector which is stuck partly open will cause a loss of fuel pressure after engine shut down, causing long crank times
to be noticed on some engines.
