1995 J30 Tachometer gone wild?

[croat]

Hoping someone can give me some advice. The Tach on my J30 seems to have a problem. It just seems to jump all over the place and show that I am running at 5-6K for the first 20 min. of driving and then usually drops down to about 4K for the rest but the whole time it keeps "flickering" up and down (+/-1-2K). The car definitvely doesn't seem to be revving as high as it indicates so I'm thinking it's an electrical problem....but why does it usually drop down after driving around for a while?

[MattB]

The same problem happened to my '95 G20. The electromechanical tachometer just goes bad. Either replace it with a tach from a junked J30 or get a new one from the dealer.

[elwesso]

Thats what I was thinking too, if the car indeed drives normally than id replace your instrument cluster..

They can be had for around $60

[MattB]

Thats what I was thinking too, if the car indeed drives normally than id replace your instrument cluster..

They can be had for around $60

If you replace the whole instrument cluster you need to swap speedometers to keep the proper odometer reading.

[Lanny_J30]

My 1997 J30 tach has a similar problem were it is either dead or swings wildly between zero and its max reading. As some have suggested in other threads, I have removed the instrumant cluster, unplugged all of the electrical connections, and plugged them back in to correct a pissible bad connection. No change in the tach's behavior.

There are several J30 instrument clusters on eBay for about $60. My only concern is whether I can maintain my odomer reading. I asked one of the cluster sellers if the tach is removable so I could swap them between clusters. He said it was not. However, MattB below suggested that it was possible.

Does anyone know for sure?

[driverdriver]

Sometimes cleaning out the contacts with rubbing alcohol, solves the problem.

[Lanny_J30]

I was able to answer my own question: Yes, individual gauges can be swapped between clusters.

In my case I swapped my broken tach for one in another cluster that I got from an eBay seller. That way I kept my odometer mileage. Moreover, I reused my own cluster that was in better shape than the weathered one from the recycle yard. And I have spare speedometer and fuel/temp gauges should I ever need them.

Each gauge is held on the cluster's circuit board by screws that both hold it in place and provide an electrical connection. First, remove the clear panel on the front of the cluster, then remove the screws from the gauge and it will come out from the front.

It's nice to have a working tach again and I hope this post helps others with tach problems.

Note to driverdriver: I did try your alcohol cleaning suggestion first, but it was the gauge itself that was the problem.