What is an Oxygen Sensor and how does it work?
Every new car, and most cars produced after 1980, have an oxygen sensor. The sensor is part of the emissions control system and feeds data to the engine management computer
The goal of the sensor is to help the engine run as efficiently as possible and also to produce as few emissions as possible.
A gasoline engine uses oxygen to burn gasoline. There is a particular ratio of air and gasoline that is "perfect," and the most common ratio is 14.7:1 (different fuels have different perfect ratios ) If there is less air than this perfect ratio, then there will be fuel left over after combustion. This left over fuel creates pollution.
If there is more air than this perfect ratio, then there is excess oxygen. More nitrogen-oxide pollutants are created in this situation and can cause poor performance and even engine damage.
The oxygen sensor is positioned in the exhaust pipe and can detect the mixtures. The reason why the engine needs the oxygen sensor is because the amount of oxygen that the engine can pull in depends on all sorts of things, such as the altitude, the temperature of the air, the temperature of the engine, the barometric pressure, the load on the engine, etc.
When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing. Your car performs poorly and uses more fuel than it needs to.