See Figures 1, 2, 3 and 4
The Throttle Body Fuel Injection (TBI) system consists of a single fuel injector mounted inside the throttle body. The fuel delivery system provides a constant supply of pressurized fuel to the fuel injector. The amount of injected fuel is controlled by the Engine Control Module (ECM).
During system operation, the ECM uses various sensors to convert the engine's operating conditions into electronic signals. Sensor inputs are used by the ECM to determine the specific fuel requirements of the engine and to calculate the optimum air/fuel mixture.
The ECM controls the amount of fuel supplied to the engine using the fuel injector. By varying the electric pulse to the injector, the duration of time the fuel injector remains open can be controlled. This allows the ECM to precisely meter the fuel supplied to the engine, providing the optimum air/fuel mixture to the engine, under various operating conditions.