IAT Sensor resistor?

[BoyntonStu]

This is not ME. From another Forum.

IAT = Intake Air Temperature

Make it read colder than actual and your computer will lean the mixture.

Just added this: http://www.youtube.com/watch?v=NaZGsVmQBbA

And this: http://www.3si.org/wiki/index.php/Intake_Air_Temperature_Sensor

BoyntonStu

This may be slightly off topic, but we are for getting more mileage....right?

Met a chap who mentioned that I should try some performance chips as they increase power etc and usually improve the mileage as well. So I started checking out things on the Internet, found one for a 2003 Chevy Venture which stated a guaranteed increase of 7 mpg and thought I would try one as it was only $10 or so.

Well, got an envelope with instruction sheet and a "shrink wrapped so
called module". It looked like a 1/2 watt resistor with the shrink wrap
over it, so I figured I got taken. Measured the resistance and found it
to be 21.7 K ohms. The instructions said to pull the connector off the
IAT sensor, then bend the leads to fit into the female connector and
wrap it with tape so it won't fall out. In other words the IAT sensor is not
connected at all! ScanGauge shows 3 as temp for IAT.

I went for my usual test run of 39 to 40 miles without EFIE
or HHO and I got a 31.5 % increase in mileage! It definitely had more
oomph and power. I could not believe it.... Really felt different on the
drive as well, hardly touching the gas pedal.

For 25 cents for a resistor, it is worthwhile trying it out to see what it will do in other vehicles.

[Cadillac]

The colder the air the more gas the car has to deliver in order to lit the mixture because the air is more dense. Warmer air is less dense and would require less fuel to ignite.

[JojoJaro]

So, this got me curious so I looked at the calibrations on my van.

On my Duramax, the fuel is being leaned after IAT hits around 110F till 194F. It leans it down from 100% at 110F to 96% at 194F. Looks like not much leaning. Which would make sense since Diesels run lean already.

It also leans it from -22F to 68F. I starts at 96% at -22F to 100% at 68F. So, if it is too cold, or too hot, it leans the mixture. I suspect the leaning at the low temps is to compensate for a cold cylinder and the leaning at high temps is to compensate for less dense air.

I suspect it is the same for all truck diesels.

[Cadillac]

My comments where only ment of normal gasoline atmospheric engines. I know little of diesels.

[JojoJaro]

My comments where only ment of normal gasoline atmospheric engines. I know little of diesels.

My response was not directed at you. It was just a 'stating of the facts' response.

But I believe it will be the same for gas engine. I believe the ECM will lean gasoline to compensate for a cold cylinder. How else would you explain the readings of the youtube guy.