Wednesday, November 6, 2013
Why Do Cars Shut Off Due to Air Intake Temp Sensors
Hot air is not as dense as cold air and therefore requires less fuel to balance an engines air/fuel ratio. The intake air temperature sensor keeps track of the temperature of the air going into an engine. This vital info is then used by an engines computer (PCM), which allows it to keep air/fuel mixture in balance.
Process
An intake air temperature sensor is normally positioned in the intake manifold so that its tip can meet the air going into the engine. The PCM sends around 5 volts to the sensor and waits for a voltage signal response. Air intake sensors have certain resistance reactions to different air temperatures, and this resistance will determine the voltage reading thats sent back to the PCM.
Problems
Faulty air intake temperature sensors can provide incorrect readings to a vehicles PCM. This can cause the PCM to mistake warm air for cold air, which will result in incorrect air/fuel mixture. This in turn leads to idling problems, which can cause a car to shut off, especially in cold weather. Other driving problems include trouble accelerating as well as engine surging.
Reasons
There are several reasons why an air intake temperature sensor can fail, such as bad electrical connections, which lead to incorrect sensor output. Oil from the intake manifold can also coat and contaminate the sensor, limiting its ability to properly monitor air temperature.
