Contour Enthusiasts Group Archives Forums Modifications General Mods Resistance is Futile

A little help here? I'm doing the 5k ohm resistor on the IAT wire mod . . . got some great info from the Ohio Forum. I have one last question and no one there has replied. Thought maybe someone here would.

I know it goes in the white/blue stripe IAT wire. I want to make sure the one I'm looking at is the right one. My KKM bolts to a metal intake housing with a sensor in it-- black squarish thing with a 4-wire plug. Furthest wire to the left is white/blue stripe. That's the one, right?

Kinda curious, what is putting a resistor on the IAT wire supposed to do?
-Mark

Hell no! If that's a 4-wire plug on a "metal housing", then it sounds like you're describing your mass air sensor. Don't screw with that! If you have an SVT, the IAT sensor is located on the accordian hose. Actually, if you have a non-SVT w/ the KKM, then it should be relocated to the hose anyways, so look there. The sensor is a two-wire setup, and you can splice the resistor inline with either wire (resistance is resistance).

I haven't screwed around with this mod for a few years, but here's a kinda recent page with a rundown on the mod. Works on all cars from the last 10 years or so that have an intake air temperature sensor.

IAT mod

And that, ladies and gentlemen, is why I ask.

I'm with ya now. And many thanks. Yes, it's an SVT, and I know exactly what you're talking about.

As for what it does, for the whole skinny see my post in the Ohio Forum-- it has all the tech. talk in the links. But basically the resistor keeps the computer from leaning out the intake charge at WOT-- boosting HP. Only works at WOT so it's a pretty safe mod.

Thanks again!

no, what it does, is trick the computer into thinking it is colder outside than it actually is, and it affects the car all the time.

The computer responds by adding a bit more fuel and advancing the timing some. This has some good effects (like the advanced timing) and some bad effects (like the car will run even richer, and the effects that go along with that, and an increased chance of detonation under certain circumstances)

Personally, its too haphazard an approach for me, but if it floats your boat fine, but I would absolutely NOT recommend this for a forced induction car.

FYI, I am currently working with several folks to make a self-reprogrammable "chip" available that will work for the SVT. Note, this is not something I would make money from, I simply want one to be available for me, so I am getting the proper stuff together for people to make it happen.
A word of cuation though, this type of chip is something that only people who understand engine controls, etc. should really be fooling with, because there is the possibility of damaging your engine if you do something stupid. I will keep everyone posted as things progress.

Okay, I'm not trying to be a buttwad here, but that goes against what I read in another thread on this. The most pertinent part is from Cardoc who is over in the Ohio forum a lot:

Cardoc
Assclown
Posts: 116
(7/22/01 12:59:00 am)
Reply Re: IAT Mod
--------------------------------------------------------------------------------
Ok... logic is on this.. 20 degree drop in air temp increases injector pulewidth 8%... Advance- 3% . The engine would have to first start missing and not firing to destroy a cylinder from a washout - Or a faulty injector that didn't close. We're talking about the pulsewidth.. (The milliseconds the EEC fires the injector) I have done this to many F-Body GM cars with great success and never in the last three years engine problems. To be honest Lance... the effect is only felt at WOT. Let me explain further.... - The oxygen sensors will adjust the mixture when warm.. 14.7 to 1 or approx best.. When the car goes into WOT, it disregards the O2 inputs and goes full rich depending on Engine (Coolant) and Air intake temp... Also MAF demands.

So there is no constant enrichening going on... Only at WOT... where the mixture is guaranteed to get diluted with fresh air.

Dom
1998 CSVT #3544 Toreador Red- Many mods! Ask and I shall tell...

Not trying to get in anyone's face here . . . just trying to get a handle on this mod. If I go to a Superchip (or equivalent) does that negate the need for this mod?

~ Joe

Sound like what an Apex'i S-AFC and ITC does
Rara, if you know of anyone in the Mustang world who has one of these on their Stang (and it works), then we could use it too.
The main thing is figuring out whther the S-AFC will work with our MAF's. Everything else should be easy.
For $295 (which you can get them for on Groupbuys) we would be lght years ahead of simply plug and play chips

CAM2,

I really don't think there is much different between what I said and what cardoc said.

The only difference is that Cardoc doesn't think the PCM pays attention during closed-loop operation (ie when it is not "ignoring" the O2 sensors) the rest of the stuff is almost identical (but I do think he missed the main point on borewash, but that isn't a major problem here anyway)

The computer uses the MAFS and the IAT in conjunction to determine how much air is entering the engine and how dense it is. This is all the time, not just at WOT. In essence, the engine thinks it is getting more oxygen than it is, so it puts in more fuel. Now, the the PCM does use the O2 sensors to bring the A/F ratio back into line, but now it will always run right on the very rich side of the acceptable range.

I never said I was against this mod (except in forced induction applications) in fact, I have seen several Mustangs get good gains from something this simple. My whole point is that it is not without its possible consequences. And I added that I personally would like better control over what is happening in the PCM, rather than tricking it. A Superchip alters the timing and fuel maps on its own to what they think they should be, so this would have the same effect on the superchip programming, only you would be more likely to hit the bad side effects because of the more aggressive calibration in the superchip.
The chip I mentioned I am working on getting, could prolly be best described as a "program your own" superchip (and it is a 4-position chip, great for you nitrous guys :D)


Stazi, can you get me some info on this A'pexi stuff?