[Swank911]

Looking for a little diagnostics help. Over the last few days my tach needle has been floating around, would drop to zero rpm, then bounce back up to around the correct rpm for a but never stay there, it would float and bounce around. Yesterday the needle dropped to zero and did not return.

The engine sounds fine, runs fine and I have not other issues.

The tach is original to the car, 73, 2.4L MFI, but was modified by Palo Alto when we swapped the engine for a 3.0 CIS to get signal from the CDI.

I am wondering how to make sure it is getting signal and determine if it is CDI output, wiring or an issue with the tach itself.