Sorry I posted this on another forum and re-reading it I probably didn't make it completely internationally friendly, Holden (GM) have a car here called a commodore which runs a GM DIS so for clarification that's what I'm talking about.
Thanks Metro, I have seen that article but the part I'm stuck on is the MS3 only has one ignition output as fas as I can tell which is why I purchased the expander board as well. However the expander board only has a "logic level" output which is not powerful enough to fire a coil so I was wondering if you are supposed to just use the stock GM ignitor and send the low power signal to that from the MS3X and use that to fire the coils?
I have found this which uses the BIP373 ignitiors (I think thats what you meant by the BIP323) on an MS3 without an expander board: http://www.diyautotune.com/tech_articles/using_bosch_bip373s_with_megasquirt.htm
But that just seems a waste to me, why make an expander board with 8 ignition outputs but not be able to use them to drive multi-coil applications? This is why I'm hoping there's a way to make the 8 ignition outputs on the MS3X high voltage rather than logic level signals.
Does anyone know a way to use the 8 outputs on a MS3X to drive GM coilpacks? Or do you just have to use the basic MS3 ignition output and add more high powered outputs to the board?