well my other topic seems to be locked for some reason so i will start another. I was told i need an IAC to start and idle smoothly. I purchased a neon 420a kit from symtech and it came with IAC1-a, IAC2-a, IAC1-b, and IAC2-b. From the diagram at the bottom of this page http://www.symtechlabs.com/support/docs/MSOptionCircuitGuide.pdf it shows that these wires are used for the IAC. I recieved this same form with my kit. But i also recieved a form that hand handwriting on the order info spot that said one of the wires had IAC listed as tach output, and one of them for operating the coil. I contacted symtech but wiht my experience i wont recieve an answer for about a week. What are my options? do i need to have the controller sent back, and have to rewire my entire car so i can power my coil and the IAC??? If i run without an IAC what am i going to see for problems? Is it used at all once the vehicle is warmed up?

I locked your previous topic as you were asking the same questions over and over without doing your homework. As I said in your other thread, you need to read the MSExtra manual as the information you are asking about is already covered.

Just because there are 4 wires labeled IAC does not mean they are wired internally to function with the processor as idle air controller signals. The IAC stepper motor is not a Fast Idle valve used only during cold starts. It continually receives pulses to open or close the valve to appropriately adjust the idle speed. Instead of emailing symtech and expecting a delay, why not call them if the issue demands haste? If your MSII unit was not equipped for idle control, the board needs modification. You said that a couple of the IAC wires are already dedicated for ignition output and tacho output, so it will take some rewiring and configuration if you wish to have 4-wire stepper motor control.

You ask what will be the result without an IAC? Well, if you remove it, you are going to have a gaping vacuum leak and your motor will not function correctly.

Again the MS project and concepts are all about DIY - the manuals are available and everything is available through searching here and over at http://msextra.com/forums/index.php and reading the manual.

I will even throw you a bone.

http://msextra.com/doc/ms2extra/MS2-Extra_Conversion.htm#idle

http://msextra.com/doc/ms2extra/MS2-Extra_Conversion.htm#start_idle

No one is going to hold your hand on this, you need to be proactive and do the research yourself, especially since you mentioned no one in the immediate area is able to tune for you.

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2012 2500HD LML

i do have a f-idle wire in my harness. I have been reading msextra about fast idle valve, and was wondering if anybody has used it to take place of an IAC successfully? and how did you do it?

Also what if i plug the iac and adjust it manually with something like this

http://www.modernperformance.com/manual-adjuster-9505-neon-with-cams-p-2004.html