Air Temperature Sensor ( Ambient / Intake ): Description and Operation

PURPOSE
Input from this sensor has a small effect on injector pulse width ("ON" time) and it should be regarded as a trimming rather than a control device. It supplies a measurement of air density, allowing the EFI ECM to fine-tune the air/fuel mixture. For example, air density increases as ambient temperatures fall and the ECM reacts by increasing pulse width to maintain optimum air/fuel ratio.

OPERATION
The sensor is a device whose resistance varies with changes in intake air temperature. As temperature increases, resistance decreases. Resistance changes are interpreted by the ECM as air temperature fluctuations.

Temperature / resistance relationship is as follows:

TEMP (°F / °C) OHMS

32 / 0 640
50 / 10 435
68 / 20 300
86 / 30 210
104 / 40 180
122 / 50 150

Air Temperature Sensor:

LOCATION
On top of left air cleaner intake snorkel.