Fuel Control

The PCM controls air/fuel ratio of engine by varying fuel injector on time. Mass air flow is calculated using speed density method using engine speed, manifold absolute pressure, and air temperature change.

Different fuel calculation strategies are used dependent on operational state of engine. During crank mode, a prime shot fuel pulse is delivered followed by fuel pulses determined by a crank time strategy. Cold engine operation is determined via an open loop strategy until O2 sensors have reached operating temperature. At this point, strategy enters a closed loop mode where fuel requirements are based upon state of 02 sensors, engine speed, MAP, throttle position, air temperature, battery voltage, and coolant temperature.