O2 sensor

Use of a oxygen sensor.

Main reason for a O2 sensor is to measure and produce the perfect air/fuel ratio of 14.7:1. how it works is the oxygen level in the exhaust from there it sends a voltage reading to the car ECU. From the result it recives it compairs the result to the build in log table and sends out the correct signal to the injectors to allow X amount of fuel to be spray out in the cylinder this gives maximum power with the best fuel economy. The O2 sensors only works when it is hot enough, that's why some sensors have heaters in them so it starts working sooner than a non heated (one wire) sensor.

Tools needed:

Voltmeter on DC

O2 sensor

Car or gas torch

Run the car until the O2 sensor is hot then unplug the conection and use your volt meter  red lead to signal wire and black lead to earth. when idleing the volt should display around 0V but rev the car and it should read around 1V which is rich. If the car is staying at one number all the time or 0V all the time then the sensor is broken.

http://www.aa1car.com/library/o2sensor.htm