MSD Fast Tach wiring.....only 3 wires ?

Some meters (my little Autometer) "stops" the needle wherever it "is." EG let's say it's working, engine running, and you rev the engine to 2K and shut off the key. The needle on the tach stops there at 2K.

I bet you are on the right track, tho. black ground, red ignition power, and white the trigger.


What are you using for ignition system? MSD / other CDI may not trigger it.