Question about my idle control valve

Jon k · Post by **Jon k** » Tue May 23, 2006 9:55 pm

I have a '92 BMW 525i that I am still trying to set up properly for MS-1 v3 MSnS-W 029Q2. I purchased DIYAutotune PWM Idle circuit kit.

My IAC valve is a Bosch model part num BSH046578 which seems is shared also with the E30 325i's with M20 motor...

Question is, in my service manual the stock ECU pin out says Pin 2 on engine harness is Idle Valve "pulsed ground - close signal" and Pin 29 is "pulsed ground - open signal". Is this valve compatible with the DIY Autotune kit?

The DIYAutotune kit utilizes "a simple two-part kit with a 1/4w 620ohm resistor to replace R19 and a ZTX688b to replace Q4" and only mentions wiring +12v for valve to switched +12v (done by default) and "wire the negative wire from the idle valve directly to pin 30 on the MegaSquirt DB37" but this valve is a 3 pole valve... so... am I screwed?

Post by **jsmcortina** » Wed May 24, 2006 3:24 am

Check the MS1/Extra site. There is a diagram.

James

Jon k · Post by **Jon k** » Wed May 24, 2006 7:16 am

jsmcortina wrote:Check the MS1/Extra site. There is a diagram.

James

Yeah - I just received different info from E30Tech.com.

Petercip said "Can't be done at this point. Valve uses two "motors".. one to open and one to close. MS can only control one."

scirturbo · Post by **scirturbo** » Wed May 24, 2006 9:37 am

In the past i've posted a circuit to drive the three wire valve. Some members use it on there cars with succes. Do a search for it...

SFC

----- Original Message -----
From: Jon k (jkensy@comcast.net)
To: megasquirt-mss@msefi.com (megasquirt-mss@msefi.com)
Sent: Wednesday, May 24, 2006 6:55 AM
Subject: Question about my idle control valve

I have a '92 BMW 525i that I am still trying to set up properly for MS-1 v3 MSnS-W 029Q2. I purchased DIYAutotune PWM Idle circuit kit.

My IAC valve is a Bosch model part num BSH046578 which seems is shared also with the E30 325i's with M20 motor...

Question is, in my service manual the stock ECU pin out says Pin 2 on engine harness is Idle Valve "pulsed ground - close signal" and Pin 29 is "pulsed ground - open signal". Is this valve compatible with the DIY Autotune kit?

The DIYAutotune kit utilizes "a simple two-part kit with a 1/4w 620ohm resistor to replace R19 and a ZTX688b to replace Q4" and only mentions wiring +12v for valve to switched +12v (done by default) and "wire the negative wire from the idle valve directly to pin 30 on the MegaSquirt DB37" but this valve is a 3 pole valve... so... am I screwed?

This post is at: http://www.msefi.com/viewtopic.php?p=121844#121844

Posted by email.

Jon k · Post by **Jon k** » Wed May 24, 2006 10:44 am

I guess my real question is what do I do since DIY Autotune provided a 1/4w 620ohm resistor to replace R19 and a ZTX688b to replace Q4? Build the circuit as per MSnS-E site and use my parts? Or what?

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