tach or something else

[260 z]

When I turn the key on, the tach goes to 8000 and the car is not running. I removed the tach and I get 12 volt on the green wire in the harness, 2 volts in the red with black strip and continuity to ground in the black, green with white strip ,and red with blue strip. On the tach I get 4000 ohms at the single post to the case and 320 ohms between the dual posts and the black wire show continuity to the case. Is my problem with the tach or some were else in the wiring??

Edited March 12, 2011 by 260 z

[260 z]

I spoke with nhspeedometer and they said special meters were needed to test the tach out of the car. I told them that I was getting 12 volts on the green wire and 2 volts on the red with black strip at the wiring harness with the key on. Then when the motor was running, the red with black strip would vary from 4.5 at about 800 RPM to 7.5 volts at about 3000 RPM. They thought that sounded correct and that the tach needed rebuilt or replaced. They will bench test at no charge and if it needs to be rebuilt, the cost would be about $ 185.00 plus freight.