IAT (intake air temperature) sensor question

[Hamsterman]

After some searching around TN... i know the importance of the IAT sensor, but i have a question about it...

The filter on my ct-26 has crapped out, it was a K&N, by melting/cracking off of the housing - and now i am forced to run a crappy generic filter for a bit... the tip on the filter is metal, and thus i cannot shove the IAT sensor into the end like i could on the K&N (it has a rubber end)...

my question is, will anything really change if i leave the sensor hang in the engine bay? The filter is basically in the center of the bay anyways, and the sensor would rest next to the driver strut mount, as opposed to being inside of the filter... Even if the temperature reading is different... how much of a change does the IAT sensor make for the ECU when adjusting to temperature ranges?

thanks for any help

[Hamsterman]

eh... never mind, as a temp solution it will just dangle - till i fix it

shouldn't be a big deal

lol own problem researched and solved

[Lord_Anarchy]

Other than reduced mileage, I don't see any other issues arising. You MAY get a "engine" light.

[RedPhoenix]

should be okay but get a new filter asap. also, gj on winning the cf trunk

[DarkMastyr]

Man I had my IAT sensor hanging out of my intake for a month (stupid rubber grommet degraded) and I didn't know. I didn't notice a damn thing the entire time. I did get some incredibly bad gas mileage, but I'm pretty sure that had more to do with me being stupid and buying Meijers gas. DON'T BUY MEIJERS GAS.

I'm surprised you didn't replace the IAT sensor with a MAP or MAF sensor.

[Keep]

is there a piggyback that anybody's incorporated to trick the ECU into getting *modified* readings from the AIT?

I dont know the theory behind AITs. I've never owned a car that had one.

[Meisner]

The intake air temp sensor causes the computer to change timing as the temp of the intake charge rises. It really isn't a big deal on N/A cars, but Nate you said you have a CT26. In that case it can be much more important.

Steve

[Keep]

Say I were to add length to the wiring, so that I could mount the AIT sensor near the front of the bumper (engine thinks it's getting COLD air, so it gives more spark advance)

I would run 93 octane as oposed to 87, and the ECU would keep timing more advanced, but still safely pull it if I start to knock.

That would be fun to experiment with.

[Hamsterman]

yeah... i talked to my engine guy - he said it probably isn't a big deal...


here is why i think so... how much temp. difference in air could there be from inside the air filter, and about 12 inches to the right of the air filter... the air going into the filter is coming from the drive side of the engine bay anyways, so readings shouldn't change that much, plus i would imagine the engine corrections done by the IAT are minimal

[brink]

Originally Posted by DarkMastyr

... I didn't notice a damn thing the entire time. I did get some incredibly bad gas mileage, but I'm pretty sure that had more to do with me being stupid and buying Meijers gas. DON'T BUY MEIJERS GAS.

Heh, I run meijer gas pretty consistently and haven't noticed any change in mileage or anything. Not to jack the thread, but briefly, what issues did you have with meijer gas?

[brink]

Originally Posted by theamazingnate

yeah... i talked to my engine guy - he said it probably isn't a big deal...


here is why i think so... how much temp. difference in air could there be from inside the air filter, and about 12 inches to the right of the air filter... the air going into the filter is coming from the drive side of the engine bay anyways, so readings shouldn't change that much, plus i would imagine the engine corrections done by the IAT are minimal

I'd say you're mostly right... the issue is when you're at idle. At one point I had my outside thermometer rewired to be inside the engine bay and in the air filter box both. I noticed that while driving there's a bout a 3-6 degree F higher temperature inside the airbox, same outside. While idling (such as while sitting at a stoplight) the temperature can easily jump 10-15 F.

And if your car has been run then you park forawhile, coming back even only 15 minutes later you'll find it's jumped somewhere around 30-40 F. However inside the airbox cools off within minutes of starting the car, inside the bay it stays pretty toasty for a looong time.

It should be noted that temps go down while driving, eventually. So the issue is that iniside the airbox you've got temps from more outside air than inside air all the time. While driving you're okay, while idling and for a while after launch it's mostly hot engine bay air you're getting.

And I'll note that this method isn't very scientific -- that thermometer isn't the best in the world, but it at least gives a little idea.

[sixsick6]

IAT sensors regulate a constant temp anyways. Should be right around 68º

[Hamsterman]

thanks for the information guys... i am most likely going to be adding an extension off of the turbo - like a sri, or maybe even down into the wheel well depending on what kind of room i have to route some plumbing - this way i can move the filter farther away from the hot hot manifold -

then with the piping i can just drill a hole in the tube to add the sensor... car has been fine thus far though with the sensor resting by the filter

[DarkMastyr]

Originally Posted by brink

Heh, I run meijer gas pretty consistently and haven't noticed any change in mileage or anything. Not to jack the thread, but briefly, what issues did you have with meijer gas?

Umm let's see... regular gas mileage - 23mpg combined

After Meijers gas - 14.9mpg

[rusty9]

haha ever see the "POWER CHIPS" for toyotas on ebay? they do the same thing you were thinking, fooling the ecu into thinking the intake air is colder. its just a 2 cent resistor they sell for $20 plus $15 shipping