Coil/Tachometer Issue

[TVollnogle]

I'm in the process of wringing out the wiring on my '70 240Z during restoration. Previously someone jumpered a wire between the BW wire at the ignition switch and the BW wire just before the coil thus bypassing all of the wiring in dash. I suspect this was because they were not getting power to the coil. The way it looks to me on the wiring diagram, the coil gets power from the BW wire at the ignition by (from the ignition switch) going to the BW wire at the resistor, thru the resistor to the GW wire, then to the tach, thru the tach and then via the BW wire from the tach to the coil. All wires have wrung out correctly.

The tachometer did not work when I dismantled the car, and this is where I suspect the problem lies. Does anyone have a working tach on their bench that they can check continuity on the tach connector between the two white wire terminals (BW and GW coming into the connector)? When I check mine, I have no continuity which would seem to leave an open in the circuit between the ignition and the coil. Not sure what happens inside the tach so maybe my thinking is flawed. Can any of you electrical experts help me out?

Thanks for the help.

Terry

Grand Rapids, MI

'70 240Z #3212

[LanceM]

I think you are right, I have a spare tach around but it is "in a box" somewhere. When I put in a ZX dizzy I had to jumper the BW to the GW at the resistor area to make the tach work. I do believe if the tach opens up you will not have power to the coil.