Fuel Injector(s)

TBI (Throttle Body Injection), incorporates a single fuel injector in the throttle body unit. MFI (Multiport Fuel Injection), incorporates 4 fuel injectors mounted in a fuel rail assembly. MFI system injects fuel into each cylinder head intake port.

On all models, when the solenoid coil of injector is energized by ECM, coil becomes an electromagnet. See Fig 1 or Fig 2 . This lifts injector plunger, allowing fuel under pressure to be injected into intake manifold (TBI) or cylinder head (MFI). Since fuel pressure is relatively constant, air/fuel mixtures are controlled by injector pulse width ("on" time). ECM determines proper pulse width based upon input signals received from various sensors and switches.

Timing of injector firing is determined by ECM based upon ignition signals from ignition coil.

Fig 1: Fuel Injector Components (Typical MFI)

Courtesy of SUZUKI OF AMERICA CORP.

Fig 2: Fuel Injector Components (Typical TBI)

Courtesy of SUZUKI OF AMERICA CORP.