Fuel Injection System

TBI Assembly:

The Throttle Body Injection (TBI) System consists of the ECM, various engine condition and operation sensors and the fuel system. Utilizing these inputs, the ECM calculates fuel injection quantity and timing. Because injector valve opening is a constant and fuel pressure is controlled by a regulator that is an integral part of the TBI assembly, the ECM controls injection quantity by varying the duration of injector "ON" time.

The two injectors are "ON/OFF" solenoid valves installed in the throttle body assembly on the intake manifold. The ECM sends pulses to energize (open) the injectors for varying lengths of time depending on its fuel requirement calculations, thereby controlling air/fuel ratio under a wide range of operating conditions.