First, I've read the writeup at mazspeed, another writeup somewhere else, and I've looked through several threads. I don't see an answer to what I'm wondering about.

I have a '79 that already has a 81-85 12A distributor. The problem is, the wiring to the igniters is brittle and not well-made. It doesn't look like anything I've seen in writeups. Whoever did it didn't run leads from the igniters directly to the coils. I have yellow/blue, blue/yellow and solid yellow wires coming out of the engine harness near the coils and running over to the distributor. Somewhere in there, the yellow is spliced into two wires. YB and BY wires go the neg. igniter tabs and the spliced wires from the yellow go to the pos. tabs on the igniter. The wires to the coils look unmolested but on the leading coil pos. there's the ring connector with two wires coming off it, one running back to the harness and one just has a bullet connector with nothing attached.

I can either splice the igniter leads I have from a '83 to what's coming out of the harness (replace the ugly wiring that's there) or I can run wiring directly to the coils from the igniters. If I run new wire to the coils, what do I do with the old coil wiring? I'd rather run new wiring, but I'm confused by the existing setup and don't want to rip it out without understanding why it's that way.

 

looking at the left igniter,
black wire = (+) while the other wire = coil's (-)

Get a fog lights relay
30 = main wire from battery/power source
87 (87A) = both coils (+)
86 = ground
85 = Locate a wire that has voltage when the key is "ON". this is now the ON/OFF switch.

the rest, identify which stock wires run the fuel pump and tach.

 

You lost me with the relay. What is the relay for?

 

To run a stand-alone power system to the coils instead of using the stock harness.