I recently added a late model si Discovery ignition system in my 81 RR. During the conversion I disconnected the ignition module from the supplied coil. I had absolutely no idea which terminal ran to the +ve or –ve of the coil after doing so and took a stab & I believe I got it the wrong way.

Surprisingly the vehicle ran for a short time before fading out. I reversed the wires on the coil and have been running for a few weeks but the idle is extremely erratic with a big miss now and then.

I purchased a new ignition module but do not wish to make the same mistake this time and get it right. (not a cheap item). I asked for advice from the parts supplier but they pleaded ignorant.

The new module part number is IG-D1913, apparently a three pin module even though I am only running two(2) leads from the module to coil. The loom that came with the Discovery ignition has 1 white and 1 white black wire from the module to the coil.

Can anyone assist with my wiring dilemma ?