Some rigs have ONE air temp sensor. This sensor is located in the lower intake manifold on the drivers side and thus takes it's reading of the air temp just before the air enters the cylinder. I have seen some kits that allow for relocation of that sensor into the air cleaner housing so that the temp of the air entering the air filter is being measured instead. The manufacturer of this kit claims that this is the better arrangement and better performance is the result of the relocation. The manufacturer = IST.

Anyone ever heard anything about this and why it would be better for that sensor to measure the air entering the filter than for it to measure the air temp in the lower manifold?

My thought is that maybe the computer is programed to read manifold air temps - thus semi-warm air - and if that sensor is placed where cool air is the computer will richen the mixture to a point that may be less than ideal...thus making this kit a bad thing, but they claim otherwise.

 

Well, ford eventually put it in the box rather than the manifold. But as far as the values used to do the computing go, I would have to say you'd have to look at something like a tweecer program or something similar to see if there is any numerical difference between the years where one is in the manifold & another that has it in the box.

Or find a ford engineer & ask them...

 

On my truck the sensor is already located in the airbox. Seems to me that the lower intake manifold would be a more appropriate place since the air is going to change in temp on its way to the combustion chamber, although maybe the computer knows this and compensates.

 

I will agree with Skanddocious, with it being in the manifold, but he comp will most likely have a preset to add, so if you have on in the manifold I would leave it cause it would make more sense that it would be more accurate.

 

I don't think there is really any benfit in moving the sensor to the air box unless the ECU has been programmed for it. The readings from the airbox are going to be lower and sending lower ACT readings to an ECU that has been programmed to have it in the lower manifold could possibly cause detonation as well as improper fueling.
I've noticed the ACT readings tend to fluctuate more in the lower manifold vs. having it in the airbox as per datalogs I've aquired.

 

Well, as far as the ECU being programmed for the air temp sensor being in a given location, that is where I run into a bit of confusion. The ECU in question is the ECU that comes in the FMS MAS kit which is supposedly an 89-93 MAS 302 Mustang computer. My van originally has the air temp sensor in the manifold, but I am not sure about the Mustang. What if the Mustang has it in the air box? Does that mean move it there or assume that the computer is programmed for the air temp sensor to be in the manifold???

The more I think about it the more the manifold place makes sense seeing as how those temps are very close to what the temp of the air will be in the cylinder.

 

That does make sense to me as well, but if the Mustang ECU gets its reading from the air box, then that's where I would move the ACT sensor to; where that particular ECU is programmed get those readings from. Just extend the wires to reach the airbox, and plug the port in the lower manifold. Make sure you clean th ACT sensor before remounting it; it'll probably be caked up.

 

The mustangs inlet air temperature sensor was located in the intake manifold in just about the same place as on the the truck engines.

 

I believe they moved it with MAF equipped trucks. If you have SD, it is in the manifold.