General Information

The Central Sequential Fuel Injection (Central SFI) system is controlled by the control module located in the engine compartment. The control module is the control center of the system. The basic function of the fuel system is to control fuel delivery to the engine under all operating conditions.

The main control sensor is the Heated Oxygen Sensor (HO2S). The HO2S is located in the exhaust system. The HO2S tells the control module the amount of oxygen in the exhaust gas. The control module changes the air to fuel ratio to the engine by controlling the fuel injector. Efficient catalytic converter operation requires a 14.7:1 air to fuel ratio. Because of the constant measuring and adjusting of the air to fuel ratio, the fuel injection system is called a closed loop system.

Several other important engine operation parameters include the following items:
^ The engine speed
^ The manifold pressure
^ The engine coolant temperature
^ The throttle position

These parameters determine the mode of engine operation.