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3-Wire PWM IAC Valve
Posted: Thu Mar 16, 2006 6:39 pm
by johnc32779
I am in the process of installing MSII V3 on a BMW engine which uses a 3-wire PWM IAC valve. One wire is connected to 12 volts, the another wire is used to drive the valve open and and the remaing wire to close the valve. I need guidance as how adapt MS to this IAC valve. I found a few references seaching the forms, but could not find a definitive answer. One message indicated a ""circuit is need to drive it correctly", but I could not find a circuit diagram.
Any and all help is appreciated.
Here is a link with some schematics for the additional
Posted: Thu Mar 16, 2006 10:34 pm
by John N
circuitry you'll need.
What type of BMW engine are you planning on using? I'm putting a M20B25 into a 2002
Cheers!
John N
http://www.msefi.com/viewtopic.php?t=67 ... c&start=60
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Posted: Fri Mar 17, 2006 7:37 am
by johnc32779
Thanks John for the reply.
My project is a 1989 735i (E32) engine in a 1971 BMW Bavaria (E3). I have been running with Motronic for several years now and have been waiting for MSII 60-2 timing support.
I can't explain why I didn't find the 3-wire control schematics during my initial search. Subsequently I have had a couple of message exchanges with MOPS and he reports excellent results with this configuration using MSII / V3.0. To reduce current, he recommends adding 1 to 2 ohm resistors in series with the IAC control leads.