Started my car the other day and I heard a clunk. Looked down at the starter ant the casing around the gear was cracked. I replaced the starter with a new unit. Once wired in the starter would only turn the gear and not engage the solenoid. Tried wiring it the other way and nothing happened. Brought it back to the store and it worked on the bench. So I wired both leads to the S terminal and the car will start and only run will the key is in the start position. I think there maybe an electrical problem somewhere else in the system?

Need to put the wires back the way they were. Purple = S, Yellow = R.
Do you still have a points ignition? Any voltage on the coil + wires when the key is turned to ON?