tach problem

[Boydskyking]

I have a 1980 911 that has a problem thats driving me nuts. When I turn the key on the tach moves uo to about 1100 to 1500 rpms and the engine is not running. I have unpluged the ignition box and it goes away. I have checked the ground for the box(its good) Changed the box( I have a new rebuilt box) still the same thing. Does anybody have any ideas what is the problem. I appricate any suggestions. Thanks guys

[Bob Kontak]

Check the ground for the tach. On the gauge and then where it terminates.

[Reiver]

^^^
The vast majority of gauge issues are simply mild corrosion at the connections...it's 35 years old.