igoben

So just ran accross your thread. I have a '77. I did the 280zx alternator upgrade with no complications a year ago. A couple of weeks ago I Did the 280zx dizzy upgrade and am now experiencing the same problem you are having with your tach. Last weekend the 280zx alternator fried (internal voltage regulator failed). Well the minute it fried my tacH worked perfect.... Replaced alternator and tact is back to not working under 1200 RPMS. I haven't figured out what the problem is but it's obviously related to to much voltage coming from the signal wire. So an inline restistor in theory should fix the issue. Hope this helps. Let me know if you figured out the problem on your end, I'm curious