Ok, today I removed the Capacitive Discharge system I install 37 years ago. (1972 240Z) Re-established the stock wiring on the coil etc. Car started ok! yea. BUT The tach doesn't work well. It works to about 3,000rpm, but jumps around above that. Also, when throttle is closed the tach drops to zero immediately and bounces up and down before settling down. The CD system had a wire coil behind the tach that replaced the stock wire, that of course was removed. When removing the CD system I reinstalled the white wire loop back on the tach. So what do you think is the problem?