Sup.
As I was talking to Matt in the other post and through email.
I should definitely need to turn on the Basic Setting->Codebase and outputs function->Neon/420A decorder to "neon/420A"
(I should have that option on in Megatune, because I connected my Tach pin to the Crank Position Sensor. not to the Tach wire. (I plan to run Spark later on)

But the problem is, whenever I turn on the Neon/420A setting, the engine won't start.
I also tried after the engine started and idling smoothly, then I turn the Neon/420A decoder on and burn it to the ECU, and the car died right away.

But I did the mod in this link: http://megasquirt.sourceforge.net/extra/setup-neon.html for the v3.0 board. and I took out my MS today and double checked.

The ONLY thing I see different is, I don't have the C12 capacitor in there, because the assembly guide said don't put it in. So should I put that capacitor in to work? is there other wiring I should do?

Thanks guys.

Edit: here are the close up pictures of the input mod I made on my MS: