ottawacivicgsr

I have a 93 civic with a b18c. I am using my stock tach. When the car is idling it does not work The needle does not move but when I rev the engine it goes up really fast and does not work right until 6500 rpm but it work up to 8200. Can any one help me I would like to get my tach to work again. It has done this before when I had my 1.6 was in the car!