4 wire IAC on MS3x

[glowryder]

420a

Current setup MS2
4wire IAC running on:
SPR1>JS0
SPR2>JS1
SPR3>JS2
SPR4>JS3

I am currently running MS2 and Im switching to MS3x. I am also currently running the 4 wire IAC. I plan to keep the 4 wire IAC wired to the SPR ports(pins 3,4,5,6) as id still like the IAC on the main harness of MS3. In the MS3X documentation, it says to jumper IAC>JS#. Instead i have jumpered it just like my MS2 with the SPR#>jso#. I was poking around Tuner studio, how do I tell the new MS3X that the SPR1-4 are to control the 4 wire IAC?

[dontz125]

Unless I'm out to lunch, the IAC pins are the same.

[jsmcortina]

Current setup MS2
4wire IAC running on:
SPR1>JS0
SPR2>JS1
SPR3>JS2
SPR4>JS3

Are you sure you did that and why?

No manual has ever suggested to wire it that way!

James

[glowryder]

i had work done on the MS2 long ago. the paper I got back states that was done (spr#>js# for 4wire stepper). I opened MS2 up last night to verify, and thats whats going on. Im running sequential on the MS2 (p/h BOARD AND CAM SYNC), so thats taking up ports as well, which is why I think symtech did that. The reason I thought id keep it that way on the MS3 is because i want to just swap ECUs with as little repining as possible.

[glowryder]

Heres what they sent me.



Attached the wiring diagram as well.

[jsmcortina]

There's no need to change your wiring as it will continue to work fine, but that's not a recommended way to arrange it.

The MS2 manuals from day 1 have always said to use the IAC1A,1B,2A,2B pins for four wire stepper idle and never SPRR1,2,3,4.

James

[seb209726]

how do I tell the new MS3X that the SPR1-4 are to control the 4 wire IAC?

No need to, the connection from the JS0-3 to the "main" DB37 (be it SPR or IAC) is done through jumpers. As long as the wiring is taking this into account (and it will if your setup currently uses it) then there is no issue.

[glowryder]

Ok thanks for the help. the main reason i didnt jumper js# to IAC's is also because R37's middle leg is going to IAC2B. I will be using the spark control off the expansion board, but I was nervous to remove this connection. If its safe to remove this connection ( I think it is because I will use my expansion card to drive sequential spark to my 905 511 audi coils), then Id rather do that, and wire it up more conventionally.

[racingmini_mtl]

This is simply the second ignition channel. You can just remove the whole thing or just the wire to IAC2B; that will free up the pin for your IAC valve. Nothing bad will happen from removing this either completely or partially.

Jean

[glowryder]

sweet, ill remove it. it will open the SPRs up for a knock sensor. thx!