What is one of the primary functions of the O2 sensor in an EFI system?

The primary function of the O2 sensor in an Electronic Fuel Injection (EFI) system is to provide feedback on the air/fuel mixture. This sensor measures the amount of oxygen in the exhaust gases and helps the engine control unit (ECU) determine whether the engine is running rich (too much fuel) or lean (too little fuel).

By continuously monitoring this oxygen level, the O2 sensor plays a crucial role in optimizing the combustion process to ensure efficient fuel usage and lower emissions. The ECU uses this information to make real-time adjustments to the fuel injection system, ensuring the optimal air/fuel mixture for various operating conditions. This feedback loop is essential for maintaining engine performance and fuel efficiency.

In contrast, measuring engine temperature, adjusting throttle position, and regulating fuel injection timing are functions that involve other components or systems within the EFI setup. The O2 sensor specifically targets the composition of the exhaust gases, directly influencing the calibration of the air/fuel mixture.