Throttle Body Injection

Injectors are located in throttle body unit. All models except 2.5L use 220 Series dual injector throttle body. 2.5L models use 700 Series single injector throttle body. Battery voltage is supplied to injector when ignition is on. ECM energizes injector solenoid by providing a ground path through its internal circuitry. By regulating injector ground circuit, ECM controls injector "on" time (pulse width) to provide proper amount of fuel to engine.

Pressure regulator maintains pressure to injector at 9-13 psi (.6-.9 kg/cm² ). Excess fuel passes through pressure regulator and returns to fuel tank.

In the "run" mode, ECM uses tach (RPM) signal to determine when to pulse injector. Fuel injectors are pulsed once for each engine revolution; each spray provides 1/2 the fuel required for the combustion process. Thus, 2 injections of fuel (2 rotations of crankshaft) are mixed with incoming air to produce the fuel charge for each combustion cycle. On models equipped with dual injectors in the throttle body, injectors are pulsed alternately.