I'm doing some reading, and was wondering about the IAT sensor. How does it work? Does it slowly scale back the fuel when the temperature rises, and at what temp does it start to do that?

PCM will begin reducing fuel at around 230deg IAT, temps easily reached at only 10psi Boost.


As IAT rises, EGT rises - reduce IAT by 100deg, reduce EGT by 100deg.


That is why the oft-repeated rule - gages first, then engine mods, starting with the '97 cooling improvements, including the '99 HD hi-flow waterpump and the 21" DuraMax fan.


You can 'toss' in exhaust upgrades anywhere in that initial progression, but gages will inform you of impending doom.

The IAT uses a volt reference signal that is resisted at different rates depending on tempatures.
212 deg. F = 177 ohms
194 deg. F = 241 ohms
175 deg. F = 332 ohms
158 deg. F = 467 ohms
140 deg. F = 667 ohms
122 deg. F = 973 ohms
113 deg. F = 1188ohms
104 deg. F = 1459ohms
95 deg. F = 1802 ohms
86 deg. F = 2238 ohms
77 deg. F = 2796 ohms
68 deg. F = 3520 ohms
59 deg. F = 4450 ohms
50 deg. F = 5670 ohms
41 deg. F = 7280 ohms
32 deg. F = 9420 ohms
23 deg. F = 12300ohms
14 deg. F = 16180ohms
5 deg. F = 21450 ohms
-4deg. F = 28680 ohms
-22deg. F =52700 ohms
-40deg. F =100700ohmsEdited by: quantum mechanic

QM, I found your post from awhile back when you changed your sensor, and your temps got better. What was it doing? Engine getting hot or something?

It ran a little hot, underpowered, dark exhaust and RPM would jump to 800.

Was it reading correct temperatures on your scanner when it was bad?