Tachometer needle problems

[38RAMBLER]

I have a 2004 Holiday Rambler Endeavor with the Cummins "C" diesel engine. My tachometer needle has started to bounce down and then back while driving on the road. Also it will do it sitting in an idle position. When I press the odometer reset button, it will drop off to "0" rpm. When I release the reset button, it goes back to normal reading. It doesn't do this problem all the time, but is getting more frequent. Any suggestions on where to start looking. I have a wiring detail sheet showing the terminals on the back of the cluster gauge. The voltage and the oil pressure works fine on the same gauge. Wondering if a loose wire or something on the engine where the signal is coming from? Any help will be appreciated. Thank you.

[DriVer]

Originally Posted by 38RAMBLER

Any help will be appreciated. Thank you.

38RAMBLER, I'm hoping that one of your fellow owners will chime in on your concers real soon.



Please come back and visit us often!

[deandec]

I would first check for a bad ground or loose wire connection.

Your comment that other readings are ok imply that all are on one gauge?

If that is the case, then the problem could be at the engine end of the tach wire. I cannot help with that side of things.

My boat tach does a similar thing after bouncing across some bumpy water. It is connected to the distributor cap, which your DP does not have.

[caymann]

You have a bad battery connection.
Clean your engine battery terminals as well as battery cables and you will be fine.

[38RAMBLER]

Thanks to all for the imput. I checked out all connections and found the signal wire on the back of the cluster gauge was loose and hardly making contact. Tightened up the nut and all is fine again. Again, thanks for the responses, much appreciated. Bye.