Sequential Fuel Injection

Fig 1: Sequential Fuel Injection (4.8L, 5.3L & 6.0L Shown)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Sequential Fuel Injection (8.1L Shown)

Courtesy of GENERAL MOTORS CORP.

Injectors on Sequential Fuel Injection (SFI) systems are pulsed sequentially in spark plug firing order. Main differences between sequential and simultaneous systems are injectors, wiring and the PCM.

Constant fuel pressure is maintained to the injectors. Air/fuel mixture is regulated by amount of time injector stays open (pulse width). Various sensors provide information to the PCM to control pulse width.