Tach question

[Dave Binkley <dbinkley@argotech.com>]

My tach works fine at the local repair shop on their bench, but when
installed in the car it has no signs of intelligent life.  It will
occasionally flicker a bit under hard acceleration.  This is
particularly frustrating since the wiring is pretty simple in the car
and it seems to check out ok.  Any helpful suggestions would be greatly
appreciated.

Dave Binkley
B9471930