Tachometer pegging at on and running
 

Hey guys, ever since I owned this car, the tach pegs out when I turn the key to on, starting and running the car. When I turn if off, she goes back to zero. I have an old 911 gauge that does the same thing when it comes on so I thought maybe it is the wiring.

However, I hooked up a new VDO gauge from another car and it works great. Does all the things a tach should do. So the issue is in the tach.

Any diy guides on taking about the tachs and finding the issues to look for. It can't be that hard. I pretty good a soldering and replacing components. Thought I would try fixing myself before trying to send it off.

Thanks,
Jason

I was able to get into the tach pretty easily. There are about 12-15 resistors that need to be checked. Odds are, it is one of them. I figure it has to do with the hot wire so I will trace those first and go from there.