6 pin CDI question
 

OK, so I've put a 3.0 into my 72/911. The 6 pin CDI is taking care of ignition with no problem but I'm not getting the SC tach to work. My Bentley manual shows a black & violet lead to the "engine control" and a black lead to the "engine control". Other sources just mention the blk&vio lead from the TD pin to the TD terminal on the tach. If there is a second black lead from the gage, where does it go or is there just the blk&vio lead? Any clues? Thanks
chasv:confused: