IAT resistor mod how to

[1blackz]

Ok, so I figure it would be easier to people who aren't mechanically inclined to do this mod with a solid how-to. I've never done one of these so go easy on me :/
This is for vehicles with the 6 wire maf, if you have the other maf the resistor goes in your air intake temperature sensor.
Here are the tools you will need: A soldering kit, some shrink wrap, or electrical tape, a knife or wire cutters for the splicing, 1/2 watt 5.6k ohm resistors that you can get at any radio shack for a few dollars, and a soldering gun kit which I got for 10 bucks at radioshack.
19802
The first thing is to start by removing the section that connects from the wiring harness to the maf as shown in the picture:
19801
Once you have that section off remove the stuff that is around the wires.
19803
It should look like this, move the gray wire with the red stripe away from the others:
19804
Once that is done cut it and prepare it for splicing Note: if you are going to use heat shrink wrap pick a pretty big one and be careful while soldering or you will shrink it before you get it over the joints like I did LOL
19805
Once you have it ready twist the resistor wires and the harness wires together in some fashion that you feel is good enough to hold it like so:
19806
Now solder those joints and once it cools off put the wire cover back on:
19807
Now if you need help with the soldering here is a link to a basic how-to video: http://www.youtube.com/watch?v=BLfXXRfRIzY
Any questions about the effects and whether to do it or not would be in this thread: http://teamzx2.com/threads/1622-40-Mpg?
All credit for this idea goes to mechtech, I just simply wrote a more detailed how to with some pictures

[mellowness65]

This is an IAT mod. IAC is what keeps your car running at idle

[1blackz]

LOL I got it right in the thread, messed up the title, meant IAT

[SR2000]

damn nice!!! repped!!!! btw Why should someone do this? I cant remember, but I believe SCT does this?

[1blackz]

Not everyone can afford an sct :( plus its a great poor man's mod for hypermiler's and according to the thread you get a lil extra power out of it, at least from what I understand, not really any dyno results to prove it. Hopefully in can go to the how to's where it belongs soon.

[mechtech]

This is mechtech's mod in the sticky '40+ MPG'.

It works to glean a few extra deg of advance.
And our stock computers need every swinging dick they can find!

It's nice to have pics - some people will use this. It is really only a 5 minute mod - no one should be scared of it.
Maybe this can be copied to the thread there?
[And also leave it here for search reasons.]

[1blackz]

I think it would be well served in the D.I.Y. How-to section...

[Lazzo03zx2]

Considering this mod, but does it advance timing? Is it more rounded around better MPG OR POWER....Noob here that loves working on his Z.

[TracerZX2]

^yes, yes and yes. I have it on my ZX2 with the mods listed below, I average 41.6 the last three tanks. According to my UG, with it I get about 3 more degrees advance. When I want to kick her in the fanny, it does better with the little extra. When driving for mileage, it makes a noticable difference. I bypassed mine for a full tank and dropped 2.76 MPG for the tank driving my weekly routine. The weather was similar enough to the week before and week after that most of the difference couldn't have been environmental. I would need to do longer testing to confirm it.

[Lazzo03zx2]

Thanks for the quick reply

[TracerZX2]

Thanks for the quick reply
Glad it was helpful

[99zx2sport]

doesnt this cause long term engine damage if ran on the constant? if not, could i do it on a 4 wire MAF?

[Lazzo03zx2]

I just did this mod and im wondering the same thing, is their long term effects with this mod? How long have yall been running this set up? Is their anyway to tell if i did this mod incorrect? I knw thats alot of Qs, buy maybe yall can explain further on how this works.

[CJW]

Long term you are changing the output of the sensor, positive or negatively. But that being said, long term I have had SCT running my car and haven't had any negative effects, and in it I control a lot more than this resistor does.

[mechtech]

The reason I strongly suggested 5.6 k Ohm is because it only changes [lies to the computer !]the air temp by 10-20 degrees. [It changes a bit when cold or hot outside.]
This will not be eventually compensated for or over ridden by the computer. It will always think the air temp is a bit cooler, that's all. And, 5.6 k Ohm is a common resistor to obtain.

Solder it in series with either the coming or going wire to the IAT sensor.

[TracerZX2]

There should be no long term effect as CJ and Mechie explained, by lying to the computer about the outdoor air temp (actually intake air temp) you are getting a couple degrees more advance and entering a lean burn state a bit quicker. It is awesome for hypermiling. Since you are at lean burn, if you hear any pinging I would advise stepping up from 87 octane to 89 octane or step off of the gas pedal, particularly if you can find squeezins in mid-grade for same price as straight gas. This should only be any issue what so ever in the warmer months

[TracerZX2]

doesnt this cause long term engine damage if ran on the constant? if not, could i do it on a 4 wire MAF? It goes on the IAT not the MAF, so yes. Select one of the two wires to/from the IAT sensor and install it inline. Which of the two wires does not matter

[Mimino]

It goes on the IAT not the MAF, so yes. Select one of the two wires to/from the IAT sensor and install it inline. Which of the two wires does not matter

i think he was referring to the pots mod. pots will cause issues (overheating) if left on constantly, especially when idling, since it's lying to the computer about the engine temperature (by reporting lower temps and fan never kicking in).

[TracerZX2]

^thanks for clarifying Victor, I didn't even consider confusing this for POTS. This mods uses a very small 5.6K ohm resistor. POTS uses between 15K and 30K ohms. It does different things. If you are going to run this and POTS, you have to to use a 3 position toggle or a SPDT relay as the POTS will be rendered useless otherwise.

The reason this can be left on all of the time is that you are only fibbing a little to the computer. The fib seems within the realm of possibility so it sees no reason to figure out that you are being untruthful. I drove my car through the hottest parts of the summer last year, I never noticed any temperature increases in my engine or other problems associated with POTS being on all the time. POTS on the other hand tells the computer that the pen is blue even when everyone can see that the pen is red, so to negate your lying, it simply says that now all pens are now red, not matter what color they really are and for some reason quits listening to the coolant temp sensor, somehow now believing that it is just as much of a liar as you are. This is of course complete and total oversimplification.

[Lazzo03zx2]

Thank you mech, i really enjoy the mod.

[99zx2sport]

^thanks for clarifying Victor, I didn't even consider confusing this for POTS. This mods uses a very small 5.6K ohm resistor. POTS uses between 15K and 30K ohms. It does different things. If you are going to run this and POTS, you have to to use a 3 position toggle or a SPDT relay as the POTS will be rendered useless otherwise.

The reason this can be left on all of the time is that you are only fibbing a little to the computer. The fib seems within the realm of possibility so it sees no reason to figure out that you are being untruthful. I drove my car through the hottest parts of the summer last year, I never noticed any temperature increases in my engine or other problems associated with POTS being on all the time. POTS on the other hand tells the computer that the pen is blue even when everyone can see that the pen is red, so to negate your lying, it simply says that now all pens are now red, not matter what color they really are and for some reason quits listening to the coolant temp sensor, somehow now believing that it is just as much of a liar as you are. This is of course complete and total oversimplification. yes i was thinking about pots mod, that is what i thought this mod was the same as. my bad lol, so it advances timing a little? and what wire would i have to cut

[TracerZX2]

Since you have 4 wire maf with two with IAT next to it, either of the two wires on the IAT, which one makes no difference. If you want to do pots as well let me know and I can draw up how to do that. I have a 98 in drive so I can show pictures of it as well.

[99zx2sport]

Since you have 4 wire maf with two with IAT next to it, either of the two wires on the IAT, which one makes no difference. If you want to do pots as well let me know and I can draw up how to do that. I have a 98 in drive so I can show pictures of it as well. i dont want to do pots, but the iat mod looks cool, i could use more timing and better mpg. if its not too much trouble can you show me a pic or something, im more of a visual learner lol. i dont want to mess it up. thanks

[Mimino]

i'd do a pots mod, just feeling lazy. i can definitely feel a difference when the car is not up to the temp yet (even with the vit sct tune i have), so pots would def. be beneficial, just don't forget to turn it off lol

[TracerZX2]

will take pics for you when I am home. No biggie.

Vic, the pots does work for extra kick in pants, however, the 5.6K ohm is mainly for improved FE and remains on at all time and is ONLY connected to the IAT. Unless your car is like mine, I have a single pole double throw relay inline so that I can select 5.6K or POTS. POTS gives me a red warning light as well since I use a DPST switch so my old brain doesn't forget to turn it off. The switch sits right next to my injector cutoff switch so that if I need a little pop of power, I can get it.

[99zx2sport]

will take pics for you when I am home. No biggie. thanks man

[jtbacks]

Sorry for reviving a somewhat dead thread, I've been searching and looking a lot at the POTS mod. Now the 5.6k Ohm resistor used on the IAT is used for somewhat little better MPGs, now isn't the POTS mod the thing you do to the ECT with a 27k Ohm resistor so that the engine thinks its cold and runs more gas, and more air? Or am I completely confused with what is going on here lol.

Sorry if this has been addressed somewhere else I've been trying to look.

[TracerZX2]

Correct, you are, only the IAT is modified slightly on a normal basis and IAT and ECT are both modified to a larger degree with the POTS mod. They serve two different purposes and the IAT can be run constantly and the computer will not learn around it. I have a UG hooked up in my car and IAT is one of the points I monitor constantly, so I do know that it hasn't been learned around. POTS will be learned around by the computer as the ECU figures out that you are lying to it.

There is a simple way to have both with one switch controlling and only one wire having to go through the firewall.
http://teamzx2.com/threads/36016-How-to-have-both-POTS-and-IAT-Resistor-mod

[jtbacks]

So essentially flip of a switch you get 5.6k ohms on the IAT and then another flip you get 27k ohms on the IAT and ECT for an extra kick in the pants? that's pretty cool. Now I've heard that you have to run mid grade sometimes to use the 27k ohms?

Again newb questions but I like these "switch" mods for a little extra it's very innovative and stuff.

[TracerZX2]

You hit right on it. I run 89 octane all time since it is same price around here and I really do in multiple tank test get ever so slightly higher mileage with midgrade, plus it is less likely to knock and ping. I like having the visual indicator that I have POTS on also, kinda like building in an idiot light for me.

[FM_Bomb_Saw]

So... If my maf wires aren't 6 wires in one group, but rather 4 and 2... could I still do this? I can take a picture and show you what I mean tomorrow.. I have a 98' ZX2 ATX with no mods done right now... Planning on doing the Knocker mod within the next few days followed by this one if I had enough time..

[tradesman351]

Ok, here's a newb question for you. I went to my local radio shack and they only had a 4.7k resistor. Would this work or does it need to be 5.6k?

[RioZX2]

Bomb_saw you can connect the resistor to any one of the 2 wires coming out of the IAT sensor. Tracer mentioned it in post #17.