In dash tach works problems

I put a Petronix Flamethrower II and a matching coil in my M-code. The tach hasn't worked quite right. I never had the tach hooked up to the distributor with points, so I am not sure what my problem is. Sometimes it appears to be working correctly up to about 2,500 rpms and other times it just doesn't work. I am not sure if I have a wiring problem or if it is something I need to change to match the new electronics in the distributor. Any suggestions or experiences would be appreciated.

Check the wiring first.
With an indash Tach the wire from the ignition switch should run through the Tach and then to the coil.

1970twisterspecial wrote:

Check the wiring first.
With an indash Tach the wire from the ignition switch should run through the Tach and then to the coil.

Yah, I looked at my wiring diagram and it looks like there is a "keyed live" wire that comes from the fuse box to the tach (red w/yellow tracer). I had an earlier problem with the car starting but not running with lack of current through the tach wire (ran another "keyed live" wire that was already in the wiring harness to the coil in addition to the tach wire). I think this probably explains my problem - somewhere I have a dead wire or bad connection. The reverse wire loop, which is on the same connection, works and appears to be on the same ignition plug. I'll have to check my wiring with a continuity light. Thanks.