tachometer works intermitently
 

I was wondering if anyone could help me. I have a 1990 convertible and the tachometer would not work when i started it up . After about 10 minutes of driving it suddenly turned on and ran fine and then a day later it suddenly stopped working again. Any ideas as to why this is happening and how do i fix it? Any help would be appreciated.

Check to see that your trailing coil pack is sufficiently grounded, and that the wiring harness to/from it is in good condition. The tach works from a signal off the trailing coil. The trailing coil just grounds by contact with the body of the car. This is a very common problem, and there is a great thread where HAILERS tells a guy how to get it working by jumping the female bullet connector on the coil pack to a wire behind the tac, I just can't remember which wire. . Search, search, search