OHC Temp sensor accuracy
#1
10-19-2009
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OHC Temp sensor accuracy
Anyone elses temp sensor off by 10 degrees or more? My scanguage will show intake temp, say at 60 and my OHC will show 65 
I know AIT is probably 5-10 degrees hotter than ambient, so that puts my OHC 10-15 hotter than actual temps. I changed the position of the sensor, switched sensor and still get hotter temps. I might re-wire it to see if its the wiring causing a difference in resistance readings. I just wanna know if anyone else had noticed that.
I know AIT is probably 5-10 degrees hotter than ambient, so that puts my OHC 10-15 hotter than actual temps. I changed the position of the sensor, switched sensor and still get hotter temps. I might re-wire it to see if its the wiring causing a difference in resistance readings. I just wanna know if anyone else had noticed that.
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#5
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air intake temp will be close to ambient, since air is outside in the ambient it will be VERY close to outside temp. I had my scanguage on my wife's camry. air intake temp would be 5-7 degrees hotter than outside temp displayed by her car. So in my case.....AIT, is a bit hotter than ambient (Normal), OHC is hotter than AIT (Not normal)...that doesnt make sense. OHC should atleast equal AIT...it should be lower actually, but Id be happy if AIT = OHC
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10-19-2009
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So youre saying the air intake temp, which is under the hood, where its hotter than ambient should be lower than ambient temperatures? That doesnt make sense. The temp sensor for the OHC is not under the hood, its outside where its cooler. The AIT sensor is right by the MAFS, where it gets HOT from engine heat. So why would AIT be lower than ambient?
#8
10-19-2009
So youre saying the air intake temp, which is under the hood, where its hotter than ambient should be lower than ambient temperatures? That doesnt make sense. The temp sensor for the OHC is not under the hood, its outside where its cooler. The AIT sensor is right by the MAFS, where it gets HOT from engine heat. So why would AIT be lower than ambient?
Last edited by RangerNDog; 10-19-2009 at 12:54 PM. Reason: Because today I am freaking retarted.
#10
10-19-2009
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I am going to assume that you have the stock intake. If you look at where it actually draws in the air it, it is from the outside right behind/beside the headlight. The reason the air is cooler is because the truck is moving and "making" a wind chill. The AIT sensor isn't programmed to compensate for the moving air so it read what the air is thus being cooler than the ambient temperature. The air may warm a lil but the short amount of time the air is in the intake tube before it reaches the AIT it should not warm much. The AIT should read as cool or cooler than the OHC except when you are moving at low speeds or idling.
#13
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I have the same problem as the OP. Does anyone know off hand what gauge wire the stock harness for the OAT temp sensor is? I have often suspected that improper resistance may be the culprit. Though in my case I don't have the speed sensor wire hooked up; I suppose I should do that before I rewire the whole thing.
#14
10-19-2009
Then I guess Im confused as to when the OHC stops the temp from moving. I thought that the VSS would not let the temp climb at idle and would let the temps change at any speeds above 0mph. Ive been driving through COLD weather @ hwy speeds and OHC reads something like 70F so I thought my sensor was bad. But what youre saying is that the temp wont change at idle and hwy speeds? hmmm....my Silverado would change temps at hwy speeds and the temp was in the mirror....I might be able to rig one up for a lil test and see how accurate the OHC is.
#15
10-19-2009
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