So I bought a large tach and small clock from a guy down here in LA. Its face is a darker black than the rest of my cluster so I guess that means its from the 80s.

I put the tach and clock in without difficulty. But when I turn the key to KP II without starting the car the tach jumps to 3500 RPM. If I let the car sit this way the tach climbs slowly.

When I start the car and it idles, the tach reads somewhere over 4000. I drove the car a little and after twenty minutes of driving the tach read 5000 at idle.

Interestingly the needle still jumps to 3500 with key in KP II even if I've unplugged both the tach and the clock. Also still does its slow climb. I understand that it's powered by the pins on the cluster.

Thoughts anyone? I know I can get my money back on this one if necessary. Is the tach bad?

Thanks,
Spencer

PS the clock runs fine.