3 wire to 2 wire IAC conversion
 

I posted this at the Uberdata site but here its is here.

I did this conversion yesterday. It wasn't that tough just irritating. The wiring diagram is here. http://www.turbod16.com/viewtopic.php?t=3572 Just scroll down the first diagram and read. I have a Y8 mani with a 2 wire on it already so I figured I would just have to change the plug and repin the harness. I was wrong. It turns out the Y7 tb will not work properly without the IAC hooked up. So I had to take an old ass Y8 TB I had lying around and use that. All is solved.

So in conclusion you need to get a plug for a 2 wire IAC plug ( If you already have the IAC) I used a coolant temp plug off an old harness.

Next, cut the orange and leave it, (I left it connected to the harness) Then wire the remaining 2 wire to the proper wires on your new plug.( the colors on mine weren't the same as the picture because it was from the temp sensors so I matched the orientaion of the wires to the picture.)

Next you need to repin your harness. Heres a tip, to get the wires out of the harness lift out the white locking block in the middle of the plug. I fought with it for a few minutes before noticing you have to unclick the block and lift it up to unlock the wiring pins. You then follow the instrustions on the link. Move the one wire over. You dont have to remove the other one like it says because its going to a dead socket anyway.
A14 to A12 if I remember correctly.

Next you need to install your Y8/Z6/B16 or whatever TB your using that doesn't have the IAC in it. You will need more 5/16 tubing, like 3 feet.

Now your pretty much done. Fire it up and it will idle at high idle when cold and come down nicely when warm. No more bouncy!

Re:3 wire to 2 wire IAC conversion
 

hope you didn't waste too much time figuring it out. i just posted the same issue and figured it out here, h-t, importlounge, and possibly on turbod16 too for anyone else having to go through the same problem 2 weeks ago. looks like you figured it out though...good job.

that's what i like about these sites. someone has an issue and either gets help and fixes it or figures it out and posts the solutions to help others.

Re:3 wire to 2 wire IAC conversion
 

Your post I remember, or it was Warwagon on Uberdata. I was just rehashing my ordeal to let people know its not that big a deal if you have all the parts. Did you have to change your TB too?

Re:3 wire to 2 wire IAC conversion
 

yeah...had to change tb too. i was trying to keep it on so when i had to go to get emissions done i wouldn't have to change so many things back, but the y7 iacv causes a vac leak w/in the system unlike the y8 iacv if it's disabled.

Re:3 wire to 2 wire IAC conversion
 

couldn't you of just used a y8 manifold from an auto since they both have the three wire IACV on the TB?

Re:3 wire to 2 wire IAC conversion
 

when you chip an ecu you have to do 5speed. there isn't support for auto when it comes to programmable engine management. therefore, you have to do the 2 wire iacv swap.

Re:3 wire to 2 wire IAC conversion
 

i guess i didn't understand the question or dilema. i thought he was saying he had a y7 and was putting a y8 IM onto it but the y8 had a two wire IACV so he had to convert it. thats why i was saying use the auto y8 IM because all the sensors are the same and it has the 3 wire IACV on the TB.

Re:3 wire to 2 wire IAC conversion
 

I converted so I can use an ODBI computer. OBDI cars only had a 2 wire IAC.

Re:3 wire to 2 wire IAC conversion
 

if we were staying obd2 we can either:
1. keep the 3 wire iacv using the y7 tb
2. use y8 auto that has 3 wire iacv

the thing is, since we converted to obd1 to be able to run programmable engine management we have to use an obd1 5sp ecu that only supports 2 wire iacv. that's why the 2 wire conversion is necessary.

Re:3 wire to 2 wire IAC conversion
 

cool, learn something new everyday. ;D