I have a 1988 Cougar (V8). Recently I purchased an MSD 6A, Blaster Coil and adapter harness. The car starts and runs fine, but the tach does not work. Does anyone know how to resolve this?
Doesn't note #2 on page 33 in the Installation Instructions manual explain it clearly enough?
The darkgreen/yellow wire that goes to the coil should be disconnected, and plugged into the "tach output" terminal on the end of the MSD box.
There's a few "branches" to that wire though... one branch goes to the TFI module on the distributor, one to the self-test connector, and one that goes inside to (okay, from) the tach. You cut the branch coming from the tach, and connect it to the MSD.