OK the keyswitch was bad in my RX-7 so I picked up an aftermarket ignition switch. I got the battery, starter and ignition wired right. I'm reasonably sure I got the fuel pump wired right too. I have a wire that (according to Chilton wiring diagram) goes to the voltage regulator? It is a heavy gauge wire... and IIRC it's black/yellow or black/white. I hooked it up to the ignition switch in the "run" position.



Also is it normal that my tach reads at about 4-5krpm when the engine is not running but the key is on? I see there is a voltage gauge in the tach, is that how it measures RPM is by how many volts the alternator is putting out? That seems extremely unreliable...

 

That is your voltage guage. The early sevens didn't have a dedicated voltage indicator, so it shows you before you start the car... it is normal. It has nothing to do with rpm (before the car is started).