Hot Rods Tachometer

Can anyone tell me how a single wire tach from Westach hooks up?

 

Well, any tach needs the negative coil hookup to determine rpm. So that's my guess as to where to connect the single wire. Negative side of coil has +12v, just with rapid cycling between +12v and zero volts when running. Your tach probably has a capacitor inside to provide a steady voltage for the operating electronics. Grounds through the case/mount. That's my best guess how it works and connections.

 

The single wire tach , was normally used with Diesel engines , it was triggered off stator windings on the alternator

 

And or a sensor on the crank pulley, or on semi trucks, off the flywheel through a hole in the BH.

 

Which tach?

https://www.westach.com/tachometers

They tell you what signal it takes....when you click on the link for that tach.