Take a look here for wiring the Opto, MS2X
There is a diagram for wiring V3.0 board to get a signal from the dizzy.
These diagrams are for a 24V engine but the circuit is the same.

They show adding a 150R to the existing 390R, generally get the 390 out and just use a 450R for the pullup.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.