Saturday, January 11, 2014
Why Must the Air Fuel Ratio Be Maintained
Oxygen sensors (02 sensors) and the powertrain control module (PCM) of a vehicles engine work together to maintain an automobiles air-fuel ratio. Air-fuel ratio must be maintained for a vehicle to have low emissions and good fuel economy.
02 Sensor
02 sensors keep track of fuel mixture within a vehicle by reacting to oxygen in its exhaust that has not been burned. The sensor creates a voltage signal that goes up when air-fuel mixture gets rich and down when air-fuel mixture becomes lean.
PCM
The PCM reads the voltage signal from the 02 sensor and bases its decision on that information. If it reads a signal that indicates a rich mixture, it lowers the amount of fuel being sent to the engine to make the mixture lean again. If the signal indicates a lean mixture, it increases fuel to the engine to make the mixture rich again.
False Reading
A PCM can make the wrong decisions due to a bad 02 sensor. A faulty 02 sensor may signal a lean mixture even if thats not the case. This can lead to a vehicle burning more fuel.
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