My mistake, the yellow wire is for manual transmission. On the blue plug on the ignition switch, the purple wire coming out is the one that needs to run to the small post on starter. That is the wire that should show voltage only when the key is in the "Crank" position. I would just run a new wire from that point through the firewall and to the small post on the starter to eliminate that pieced together hack job wiring you described to me over the phone. Since that original wire is all spliced and pieced together half assed that throws up a big red flag to me. Also the fact that the 2 extra feed wires the go to the big post on the starter are missing also confuses me and points to even more customization by the previous owner. You also mention only getting any voltage readings showing 11+ volts? That should be plenty of voltage to crank that starter. Are you sure the red cable from the battery to the starter is in good condition? There could be corrosion in that cable at the ends hurting the amperage being pumped through the cable, even though it is showing good voltage at the other end.