Are you running the Opto or going direct to the processer? But a pullup is needed since the dizzy is just a switch. I get +5V from within the VR conditioning area to install a 450 Ohm 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.