3-Wire PWM IAC with MS2 PCB3.57

[tomeric914]

I have searched through the megamanual and am still confused on how to wire the 3-wire IAC valve on my Porsche 3.2 Motronic to MS conversion.

I plan on using "MegaSquirt-II EMS System - SMD PCB3.57 Assembled ECU" from DIYAutoTune and read that:

"Pulse-Width Modulated (PWM) Idle Valves are now natively supported by the PCBv3.57 hardware without the need for modification. This is one of the coolest features as this was a very common modification that will no longer be needed. The circuitry on the PCBv3.57 will control a standard on/off fast idle valve, or a 2/3 wire PWM Idle valve! "

However, when reviewing the megamanual at http://www.megamanual.com/ms2/IAC.htm I read that:

"Note that if you are using a PWM Idle valve, such as those used in some Ford products, the standard transistor is not sufficient to power the valve directly..." and it continues on with the modification.

Do I need to perform the modification with the SMD PCB3.57?

[Matt Cramer]

However, when reviewing the megamanual at http://www.megamanual.com/ms2/IAC.htm I read that:

"Note that if you are using a PWM Idle valve, such as those used in some Ford products, the standard transistor is not sufficient to power the valve directly..." and it continues on with the modification.

Do I need to perform the modification with the SMD PCB3.57?

That text is for the V3.0; V3.57s have a beefier transistor.

[tomeric914]

Thanks Matt. How do I wire it up? Does anything need to be jumpered?

I found a diagram that shows the 3 wire IAC with 12 volts to the center connection, FIdle to one of the outer connections and a resistor of some variety on the other connection but am not sure if that is how it gets wired to the 3.57 board or not.

3.57 board information isn't that easy to find. Is there a link to 3.57 information?

[Bernard Fife]

There's a whole section of the manual table of contents on the 3.57 board here: http://www.megamanual.com/mtabcon.htm#357