Feedback System

PCM calculates injection pulse width by processing input signals from ECT, HO2S, TP, MAF and other sensors. After receiving signals from sensors detecting engine conditions, PCM can adjust air/fuel ratio to optimally control exhaust emissions and engine performance.

Fuel injection system incorporates mixture ratio feedback. It is designed to maintain a precise mixture ratio. Through input signals from the front and rear Heated Oxygen Sensors (HO2S), PCM continuously monitors itself to stay within an acceptable emissions output range. However, this feedback system can be overridden and will operate in open loop when one or more of the following conditions exist:

• Starting.
• Engine and/or oxygen sensor cold.
• Driving at high speeds or under heavy load.
• Oxygen sensor monitors a too rich condition for over 10 seconds.
• Fuel shutoff solenoid is activated.
• Vehicle is decelerating.
• EGR temperature sensor is malfunctioning.