emcon5

I want to check the timing of my 82 SC, as it is pinging a bit under hard acceleration. The instructions for the tach feature of my multimeter say to connect it to the negative side of the coil, and to ground.

I looked at my coil, and can't figure out which is the negative side. One side has an arrow, ant the other has what appears to be an "A". There is also a picture on the coil showing a test meter of some kind wired to both coil connections, indicating that this is Verboten. The Haynes manual says to follow the manufacturer's instructions, the Bentley doesn't mention it at all.

How do I connect this thing?

Tom
82 911 SC Coupe