Tach jumpy?

[JRust]

I am just putting my gages back in after paint job. I noticed my tach wich I had forgot works sort of? When reving the engine it moves kinda close to the rpm but is real bouncy(jumps about 3000 rpm randomly). Anyone have this problem & how do you fix it?

[JmuRiz]

I'm in the same boat too, sorry but I can't help you out. I'm going to play around with it some before the season. I'll let you know if I fnd anything out. Kindda nerve racking when you see that needle bounce...just hope it's not really revving that fast, or high some times!

Nathan

[philinjax]

Jamie,
I think you are stuck with the bouncing tach needle. The damping circuit is defective. Your best bet may be to find a used tach that works. You could also send it the N. Hollywood Speedo for repair but, that might cost a lot more than a good used unit.
Phil

[Dave at Pelican Parts]

Check the points and condensor--those "feed" the signal to the tach. If they're a bit wonky, you'll get a poor tach reading. Also check the wiring from there through the relay board to the tach. Make sure the tach is getting good power and ground.

And if that all checks out and you're still having problems, have the tach rebuilt.

--DD

[Mark Howard]

Same thing happened to me after my repaint. Recheck your wiring with the PP flow diagram. Print all pages of the diagram and tape them together for the full effect. My problem was just a bad ground (misplaced brown wire).

Good luck.