My tach is off

[brianl]

My 71 has the dash with the tachometer, and the tach is reading incorrectly. It's reading high. I hooked up a cheap tach from Autozone and as I suspected, it reads correctly. What could cause my factory tach to be showing high RPMs? And how would I fix it?

FYI- My dash tach reads around 3800 RPM at 65 mph with a 3.23 rear axle gear ratio.

[odzking]

Could be the tach is simply going bad. Did you try some sort of lubrication. Can't hurt, as you said it isn't working properly now.
Someone here can give you an idea of what to use.
Otherwise I'd send it to be repaired/overhauled. I am sure one of the gauge place out there can make it right.

[Tom]

Usually the tach board goes bad. Replacements are available
www.ebay.com/itm/Mopar-Replacement-Tachometer-board-RT-ENG-/161119693854?hash=item25837b6c1e:m:mWiV8Y-0cAzwKbQ9KdauSdA&vxp=mtr
I bought and installed on of these with good success.

The tach boards are adjustable, so if you are a little off....you might be able to adjust.
If way off, probably a bad part.

And....if I had the cluster out to replace the tach board, I'd put one of their solid state IVR's in too
www.ebay.com/itm/Solid-State-Mopar-Limiter-IVR3-bolt-on-Challenger-Cuda-B-body-Rallye-/161833600194?hash=item25ae08c4c2:m:mZzmJF35UaeN46o-DfLg9sA

[brianl]

Thanks guys.