This is a duplicate post from 4.6 forum but not sure which one is the right place....

So I come out of work last Friday when it's raining and muggy. I start my car and my CEL stays on. Ok. Whatever, probably nothing and drive it home.

Today I had jury duty so I ran over to Autozone that was really close nearby on lunch break. The code was IAT High Input or something like that. Guy said it was a high temperature signal from the IAT and the sensor probably just needs ot be replaced. He cleared the error for me so I could see if it was a fluke or if I would get the code again. I went home for lunch, no CEL. So I drive back to the courthouse and my CEL is on again, probably the same code but haven't checked it yet.

Wouldn't a bad IAT sensor cause driveability issues? It is currently running like usual.

Does this sound like a bad sensor or could there be another problem? The IAT sensor is simply an input for the computer, right? So if I just swap in a good one (assuming it is bad) it won't affect my tune will it?

TIA!

 

IAT shouldnt cause drive-ability issues. It is just there to measure incoming temps (obviously) and to tell teh computer to dump timing when it gets too hot. I saw this very clear over the weekend when i got my tune, the more boost, the hotter the iat's and timing gets dumped to save the motor (i am getting the message of i/c importance). If it gets too hot and the iat isnt doing its job, you can get det. Is your iat separate or incoporated into your MAF? i went to a lightning maf and had to get an outboard iat. it shouldnt affect your tune at all. When i switched to the lightning maf, i didnt have an iat anymore until i replaced it. you shouldnt tune without it,but just switching it out would be fine unless you did tune when it was bad.

 

Thanks Gordo.

It is the same standalone IAT I had before the ProCharger.

I will definitely get it replaced then. If it's sending a hi temp signal, whether it is really hi temp or not, it is telling the computer to do something I don't want it to do or that it needs to be doing. Or so that is my understanding right now.

The IAT is in the intake tube between the air filter and the blower head unit on my setup.

Thanks again.

BTW, intercool or go home.

 

hi temp signal. Actually that may affect drivablilty. If you iat is reading way hot, then you car is going to be dumping timing, so it might run like a pig if it is doing that.


i hope you are mistating the second part or i am reading it wrong. It needs to be after your blower so the car can actually read the temps. The way you described it, your car is reading ambient, it needs to read teh compressed air. The air is going to be hotter (even with teh i/c) after the blower, that is what it needs to read. That is how i understand it with blown motors. Rpms go up, boost increases, so does heat, your car needs to be able to compensate by taking timing out, with your i/c i doubt it would be much.

 

No, I did not mistate it. The way you explained it is the way I thought it should be which is why I had a hard time even finding the thing - I thought it should be after the head unit. When I couldn't find it, I started at the air cleaner and planned to trace the intake path until I found it. Didn't take long, it was right after the air cleaner on the plastic intake tube from ProCharger. It is before the head unit.

I'll go take some pics of it to show you what I mean but I am still trying to find my cable for my camera, so it may be alittle while before I post them. Anyways, I picked up the IAT from Autozone for $14 and swapped it out. No CEL after two drive cycles so it may have fixed it. I'm glad you said it would affect drivability because it did feel a little more sluggish with the CEL on. Not quite as bad as when the A/C is on but almost as bad.

Thanks again for the help Gordo, I didn't get much help in the 4.6 Tech forum. Maybe I should've asked about a wheel/tire combo or something I plan on doing five years from now if I hit the lotto. I should've known to start here...my bad.

 

gordo,

where did you get your outboard IAT?

I got one from the ford dealership for a 99- 01 lightning and the pigtail. i went to ace hardware and got a steel nut that fit the pipe thread on the IAT, i think it was 3/8 metric.

i was planning on welding the nut on the boost pipe, near the 90 degree bend towards the s/c, and just threading it in, i figured it'de be nice and air tight that way. but then i got to thinking, that's gonna get pretty hot, and i was thinking i may just put in that blue coupler at the pipe and s/c.

i'm sure everyone that gets the 42 lb injectors and lightning maf have run across this?