GMC Repair: 98 Chev 5.0 L 305 V8 K1500 4x4 automatic, intake air temp, intake air temperature

Question
Dear Sir; I want to know what effect a change in intake air temperature has upon my truck's PCM.  Does increasing or decreasing the intake air temp advance or decrease ignition timing, or does it increase or decrease injector pulse width, and by how much?  I cannot find any info pertaining to this question.  Sincerely yours, Steve

Answer
Hi
Here is a breif description of the circuit description:

The intake air temperature (IAT) sensor is a thermistor. The control module supplies the IAT sensor a reference voltage on the IAT sensor signal circuit and a ground circuit. When the IAT sensor resistance is high, indicating a cold sensor, the IAT sensor signal voltage remains near the supplied voltage and decreases the signal voltage as the sensor warms. The control module monitors the IAT sensor signal circuit in order to calculate the temperature of the air entering the engine.

It will set codes and it has an effect on fuel pulse. The PCM will also though look at the ECT (engine coolant temp sensor) for finer fuel control.

I Hope this helps
Pawl