I would like to idenitify the different wires in plug going to IAT on my 2009 GMC Acadia
Why would you want to?? If your bought a chip for your IAC to try to get more performance and economy from your Acadia, all you bought is away to shorten up your service life of your engine.
IAT Sensor = “Intake Air Temperature” sensor
AFR = Air/Fuel ratio, ideally it would be 14.7 units of air to 1 unit of fuel or 14.7:1
The IAT sensor is a passive or discrete electronic component that will simply vary its resistance depending on changes in temperature (also called a thermistor). It has a negative coefficient, meaning that the higher the temperature is, the lower the resistance it will offer to the current flow and vice versa.
Few ECUs will use the signal from the IAT sensor alone, to modify the ignition and / or injection to slightly compensate for the incoming air temperature variations. So making the computer “think” the incoming air is cold will make it do small adjustments to ignition timing and / or fuel injection and there is where the IAT Mod ideal originally came from.
It is accomplished by putting a fixed resistive value (fixed resistor) instead of the regular IAT sensor, simulating a cold intake air situation. Going back to the facts above, “the higher the temperature, the lower the resistance”, to benefit form this modification, we would need to make the resistor value high enough to make the computer “think” that the temperature is low enough. That would hopefully induce the ecu to inject more fuel and advance ignition timing accordingly, in an attempt to compensate the supposed incoming cold air.
The problem with the IAT modification:
Even more and more people that have bought those IAT mods are claiming that it does nothing. It is probably attributed to the fact that not all cars depend only on the IAT sensors alone to make the necessary changes. So, it is very probable that modifying the IAT sensor of your car will do nothing, or at least nothing noticeable.
If you successfully modify the IAT sensor and the engine makes some noticeable changes, remember that the air will not be truly colder or denser, so no extra oxygen will really be present, ending up in a richer mixture, higher emissions and very probably lower performance, unless your car is already running way too lean because any previous modification or any existing engine problem and a richer mixture will benefit its performance.
If you live in a cold area, you will notice no difference as the original IAT sensor installed in your car will already be in a better resistance value than the one you would insert. If you live in a hot area (tropic, desert), it will be worse than the ones in a cold area, as even less oxygen will be available for the combustion. If you live in a high altitude area, you will have similar or worse luck that the ones in the hot areas as oxygen and pressure progressively decrease with altitude, even if it’s cold.
Regardless of the all mentioned above, if you finally make the car computer do a positive modification by installing that 10 cents resistor, remember that changes will be on the factory program range limits or specifications anyway, computer program is still the factory installed one. All changes made by sensor modifying (any sensor), will stay in the factory specs since sensors can be read but can not bypass or override functions in the ECU, unless a modified program (Dyno Tuned) is installed.
iat sensor resistor scam do it your self performance chips ebay +20hp 50hp
Thank you for using fixya and good luck
Jun 14, 2010 |
2009 GMC Acadia