he's right about a resistor working in either direction and a VOM doesn't put out voltage when reading anything. Just go make yourself one and save the money. Now if you just really want to buy a Power Wire I will sell you one I have.

 

i posted the wrong link, i can't find the spot that airram explains how it works. i have an edge programmer but doesn't this work with the programmer?

 

Not a zener diode...

 

A VOM does put out a calibrated voltage when set in the OHMS function...

 

yes, i know. If i could find that article by airram, he explains that a resistor can't compensate like the power wire does.

 

He's full of it...the resistor mod has been done on various vehicles since port injection was introduced and that's all the power wire is. Different value resistors adjust the IAT's signal in different ways...that's why they're telling you to use a 4.7k.

 

the resistor/powerwire is not doing the compensating, the ECM is. It thinks the air is a bit cooler then it is, so it compensates for what the temp is. now if the temperature outside gets hotter, the ECM picks up a hotter temperature and adjusts.

 

Correct, the PCM sends out a voltage signal, the IAT is a variable resistor that changes with temp. As the air temp heats, the resistance goes down, thus raising the return voltage closer to the original voltage sent out to the IAT (Usually 5V on most vehicles). All the resistor does is reduce the voltage going back to the PCM enough that when the PCM converts the return voltage signal into a temp. number, it is a bit lower due to the added resistance. The PCM, then adds a little timing because it thinks the incoming air is cooler.
If you already have a tuner, you may get too much advance with the resistor/power wire because the tuner has already advanced the timing and leaned out the fuel mixture. By adding more timing from the power wire, you may have detonation issues which is not a good thing.

 

so it's probably like one of the higher horsepower programs on my programmer...

 

I gave all the numbers on what a 2.2, 3.3 and a 4.7k resistor does as far as making the PCM think the air temps are different. If I am not mistaken, the 4.7k was a bout a 44* difference while the 3.3k was 22* and the 2.2k was 11* cooler. All these numbers came out of a SC3815