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1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 04-20-2006, 11:33 PM   #1
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Ran a quick scan check with the car still idling after the 1.4 mile trip from the gas station. 14 counts of knock... and my IAT read about 26*, lowered to 21* when I opened the hood to make sure it was connected properly and still seated in the filter. I do have a Series II IAT, cause it'* smaller in diameter and longer, so it reaches into airflow better. Last time I checked, it was reading normal temps. O2 was showing lean most the time idling, flipped to rich momentarily a few times as I was looking.
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Old 04-21-2006, 12:27 AM   #2
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Ever happen to anyone else? Will IAT'* go read wrong, but still function?
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Old 04-21-2006, 09:39 AM   #3
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I could see the sensor itself being different and handing off different ohms etc which would equate to different temps at the PCM.

For example The temp is 30 degrees entering the airbox the S1 IAT provides 50ohm signal and the PCM interprets that as 30 degrees and S2 IAT provides a 70ohm signal that is interpreted as 40 degrees by the S1 pcm.but would be be 30 degrees to an S2 pcm.
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Old 04-21-2006, 10:44 AM   #4
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Hmm, it'* reading correct this morning...
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Old 04-21-2006, 12:33 PM   #5
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Double check the connections ...ensure they are clean.
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Old 04-21-2006, 07:56 PM   #6
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Watched it on the way home, seemed fine till it dropped during a WOT run to -32*, that'* right, NEGATIVE 32*. Eventually, it came back up to 59, which was still low. Ambient was about 72. Fiddled with it when I got home and readings went back up to normal. I'm trying to reason why a wiring issue would cause weird readings like that. I'm thinking it'* the sensor.
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Old 04-21-2006, 10:10 PM   #7
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I believe that they use a thermistor for the IAT, which are generally quite reliable. They do occasionally go bad, and when I was doing electronics sevicing, when they went, they could cause rather wierd readings. I think I'd swap it out.
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