Tach bouncing all over the place

[Joe8915]

90 with 91,000. The last few weeks I notice my Tach bouncing all over the place, but after the car warms up, then its operates just fine. Could this be a ground wire?

Need some advice.

Thanks

 

[gmjunkie]

90 with 91,000. The last few weeks I notice my Tach bouncing all over the place, but after the car warms up, then its operates just fine. Could this be a ground wire?

Need some advice.

Thanks

Yep,It's possible!! But it's probly the tach filter going bad!!

 

[Joe8915]

I guess i should did the search before I posted. Now is the Tach located in front or rear of block. Not a real wrench here, but what is the level of difficulty of doing this on my own. Starting to make some calls for estimate this morning.

thanks

 

[vetteoz]

'90's commonly have tacho problems. Generally a cluster problem not fixed by replacing the filter.:ugh

Filter location here
Tachometer Filter Replacement - 1990 Vert - Corvette Forum

90-92 Tachometer fix.... - Third Generation F-Body Message Boards

 

[G Winter]

The tach. in my 90 is off shows about 15 % to 20 % to high. I bypassed the filter and had no effect good or bad,did not bounce.Is as if the filter doesn't really do anything.
There are many links in how to repair the tachs like we have both in F bodies and the Vettes . It isn't easy but can be done... takes trial and error to fix them with a couple of removals of the cluster.

If you have lots of time to repair it I can look up the links.

Glenn

 

[vetteoz]

If you have lots of time to repair it I can look up the links.

Repair links are in my post above