Closed Loop

Specific values for the above conditions exist and are stored in the memory calibration module. When these Values are met, the system goes into Closed Loop operation. In closed loop, the PCM calculates the fuel required in the same manner as open loop but corrects for small errors based on the signal from the oxygen sensor. This allows the air/fuel ratio to stay very close to 14.7:1. The best mixture to minimize exhaust emissions is 14.7:1 air/fuel ratio, which allows the three way catalytic converter to operate most efficiently. Because of the constant measuring and adjusting of the air/fuel ratio, the fuel injection system is called a closed loop system.