High pressure fuel is supplied by an electric pump in the fuel tank. Pressure is regulated by the
fuel pressure regulator. The fuel injector is a solenoid operated device, controlled by the
Powertrain Control Module (PCM), that meters pressurized fuel to a single engine cylinder. The
PCM energizes the high-impedance (12.0 ohms) injector solenoid to open a normally closed ball
valve. This allows fuel to flow into the top of the injector, past the ball valve, and through a
director plate at the injector outlet.
The director plate has four machined holes that control the fuel flow, generating a spray of
finely atomized fuel at the injector tip. Fuel from the injector tip is directed at the intake valve,
causing the fuel to become further atomized and vaporized before entering the combustion
chamber. An injector stuck partly open can cause a loss of pressure after engine shutdown.
Consequently, long cranking times would be noticed on some engines. A leaking fuel pressure
regulator can also cause this.
Fuel Injector Operation And Decription