I use the VR circuit on the output of the dizzy, so you need that to interface with the optical sensor with the appropriate pull up resistor. When checking everything, make sure everything works before you try to fire it up. Use the output test mode to check the fuel pump, coil, and injector outputs before trying to crank the engine. When checking the injector outputs, use a mutlimeter and check just the plug so you don't dump fuel in your motor. I didn't use the relay board either, just did it the way Nissan does all there cars, with relays along side the engine harness. Wish I could help more, but ms3 has a few setup differences. From what it looks like, MS3 is more like a factory Nissan ECU. Good luck!