#1 can anyone tell me how the computer uses intake air temp sensor and when/how it works? i can't seem to find a good dfescription of it.

#2 i may have a computer issue with my 89 iroc 350TPI... i have a 89 305TPI with a good puter and wondering if i can swap them or what may be different? both are automatic irocs. rear end gears are different.

thanks

 

the "chip" in the computer needs to be switched out... the blue memcal/prom is what tells the computer what engine size, knock sensor, etc is under your hood. they need to match...
as far as the IAT:
manifold air temperature sensor: (MAT, IAT, smae thing, under the plenum in the back)
it tells the computer the changes in the air temp to fine-tune the air-fuel ratio...its the same as the coolant temp sensor...

 

some more info on the IAT: it is physically a different sensor than the engine coolant temp sensor, however, they both work the same way. They are both NTC's, which means that as they get warmer, sensor resistance goes DOWN, which is different from most electrical circuits that INCREASE resistance when they get warm. In other words, when the engine is cold, the ECM sees a high voltage signal from the IAT and ECT because most of the voltage returns to PCM Because the sensor has high resistance which stops the current from grounding to the intake where the sensors are. When the engine gets hot, a properly operating ECT or IAT will have a low signal voltage return to the PCM because most of the current can now flow to ground because of the decrease in resistance.

 

well from what i have the CTS and IAT are the same sensor and function the same way. i got that. what i am looking for is how does the computer use the intake air temp reading? what does it change? does it work together with the cts and maf?

mostly i want to know, if the iat sensor is bad or incorrect, how will that affect the vehicle running.

i am trying to narrow down a rich condition in closed loop - BLM 160
it runs well and has lots of new parts/sensors.

i HAVE NOT changed the MAF or IAT and the o2 was changed over a year ago before i got the car.