Need help with IAC wiring and adding more

[asumsatlil]

I have a VW MK2 Golf 16V that currently runs on MS2 V3.57. I want to add a few more things to the car, such as a PWM/IAC/stepper(something to control my idle when cold, since i have to wait for car to warm up to idle) and Boost control. But i have all of my heat sinks filled, and im confused on the wiring for helping my car have warm up idle of some sort. I've been reading over this information on it but i still find my self confused and would like some help. http://www.megamanual.com/ms2/IAC.htm#fidle.

[dontz125]

If you use a stepper IAC, then you can just use the stepper chip on the MS2 card. If you go with PWM, you'll need something a little more robust. Actually, the FIDLE circuit on a V3.57 is solid enough to do PWM IAC control, so you're already set.

Not sure what you have on the heat sink right now, but R37 & R38 can usually be removed and a heavy link thrown across the 2 holes. The HS positions can then be used for TIP122 or other suitably heavy-duty devices for boost control and any other function you might have in mind. The actual boost control mod is in the manual; the main link is at the top of the page. Don't use the MegaManual (except for theory and background info); it's a different firmware, and you'll just get confused.

[asumsatlil]

Oh so I'd only have to add the stepper iac to the harness on pin 30 and add the jumpers and id be good to go?

(1A)JS0 (under the processor socket) to IAC1A (near the DB37 connector) - this goes to Coil 1, lead A on DB37 pin 25
(1B)JS1 (under the processor socket) to IAC1B (near the DB37 connector) - this goes to Coil 1, lead B on DB37 pin 27
(2A)JS2 (under the processor socket) to IAC2A (near the DB37 connector) - this goes to Coil 2, lead A on DB37 pin 29
(2B)JS3 (under the processor socket) to IAC2B (near the DB37 connector) - this goes to Coil 2, lead B on DB37 pin 31
Install a jumper from the hole marked S12C to the hole marked JS9 (+12C)

Here is an iac I have. https://www.ecstuning.com/b-mtc-parts/i ... 6457e~mtc/ and http://www.pelicanparts.com/More_Info/0 ... 40-509-INT
They are basically the same except ones 2 pin and other is 3 pin.

[dontz125]

Well - yes, that's how you'd add stepper control, but that's not a stepper valve. If you open a few pics on the link you just posted, you'll see that it's a 2-wire PWM valve. Connect 12v from the FP relay to one wire, run the other wire back to FIDLE on the DB37. Done.

[asumsatlil]

so just a 12v power and a signal wire.

[dontz125]

" ... and a medium-current switching ground," yes.

(Sorry if I sound like an ass, and I know it's used the way you said, but any time I see someone mentioning a "signal," my brain tries to insist we're discussing something in the 5v, mA range.

Stupid brain ... )

[asumsatlil]

its all good, thanks for the help, sounds easy enough.

[asumsatlil]

does anyone have any information on adding a knock sensor? i looked in the manuals and found some one page with a on/off mode. I have a 3 pin knock sensor like this one: https://www.ecstuning.com/b-bosch-parts ... 1231036sj/
if i use that sensor i would have to give it power, ground with the signal wire to the GM ESC module it talks about, the from the module to pin 13 on the megasquirt?

Megasquirt supports knock sensing with an external interface to the knock sensor. Do not connect a sensor
directly to the Megasquirt - it will not work.
Two configurations are available - on/off or analogue.
The on/off mode can be used with a GM ESC module (16022621, 16052401)
The connection to the Megasquirt is on JS4 or JS5.
Then has a diagram for using a 1k ohm resistor from SPR3 to JS4, JS4 connected after resistor to 4.7v zener, 4.7V zener to ground.