Ok guys I need help, and yes I have search but didn't find the answer. I have a 1985 Mercury Capri RS. I installed a msd 6al. Fireup great. Now I'm installing a tach adapter 8920. This is getting me to my limits, before I throw a match to it. The red with a green line was the positive on the stock coil. The green with yellow dashes is the negative. I put the tach adapter, red in a 12v source, the black ground, the white to the msd tach output. The purple I hooked it to the green wire and nothing, put the white one from the box to the green wire, nothing. Anyone has done this?? Is the same as an 85 mustang gt carb. Need help. I'm restoring this and I'm about to burn it to the ground. Frustrating. Any help will be appreciated