MicroSquirt.com read only forum (Jan.15,2018)

I am running a fuel only microsquirt and had a heck of a time getting a clean tach signal for it. I have purchased an MSD GMR pickup to get the tach signal off the coil. It outputs a 12v square wave. Here is the MSD page- http://www.msdignition.com/2006/06-22.htm I'm not sure exactly how to hook this up to the microsquirt. I am not getting a tach reading on the microsquirt. I hooked the tach output to pin 30 optoin+ and tried the ground of the MSD unit to pin 31 optoin- and also tried straight to ground. I have verified that the MSD is outputting a tach signal. I think this is just a simple mistake of what goes where on my end. Any advice on how to get the microsquirt reading this?

I found an answer with some in depth searching. This really seems like it should have been easier to find or maybe even be in the manual. The tach output from the MSD goes to optoin+ pin 30 and you ground optoin- pin 31 to chassis ground.