Air-Fuel Ratio Feedback Factor
The ECM creates this factor utilizing the front oxygen (A/F) sensor signal. When the signal is high, the air-fuel ratio is leaner than the stoichiometric ratio. The ECM then makes the fuel injection duration longer by modifying the factor. When the signal is low showing that the mixture is rich, the ECM modifies the factor to make the injection duration shorter. In this way, the air-fuel ratio is maintained at a level close to the stoichiometric ratio at which the three-way catalytic converter acts most effectively.