I have a 92 camaro rs, automatic, 305 tbi. I just bought the car from someone and the tachometer runs almost wide open at normal operating speed. I tried disconnecting wires to distributor, and it would drop back to zero. When reconnecting it jumps back up to 2500 rpms at idle. Any suggestions would be appreciated. Thanks!

 

It's a fairly common problem, especiall with the 90-92 "half-moon" style gauges. My tach reads 1500 RPM at idle . The problem is in the printed circuit board and/or a capacitor for the tachometer. Most people who have the faulty tach readings with their gauges either try to fix it themselves (by installing a new capacitor, printed circuit board, or a used gauge cluster from another car, but there is no guarantee that the used one will work right), send it to a gauge specialty shop for repairs, or just install an aftermarket tach. If you want it fixed, I would search the internet or your local phone book for a specialty shop that deals with gauge cluster repairs.

Just keep in mind that GM never intended the tach in these cars to really be used for accurate tuning, it was really just a trim piece.

But, it would be a good idea to make absolutely sure that the tach is truly off by hooking your car up to a scan tool or datalog and monitor the actual RPMs that the computer is seeing, just to make sure.

 

ya know. it might have settings on the back to switch from 4,6, or 8 cylinders...if its an aftermarket tach..

 

Go to this link and it will get yours running like a brand new tach.
https://www.thirdgen.org/forums/electronics/357893-90-92-tachometer-fix.html

 

I think you may have mistakenly posted the wrong link here. This one just goes right back to this same thread!

 

Link fixed

 

Fixed it in the text but not the actual link. For anyone else needing the link, here it is!

https://www.thirdgen.org/forums/elec...meter-fix.html