Tachometer not working or hanging at 4-5k RPM
 

The tachometer on my 1983 GS does not work from start up, and takes a long extended period of driving to actually turn on. Even when it does, the tachometer will not go above 4.5k RPM, even though I can hear and feel the engine revving beyond that. I disconnected the cables from the coils and reconnected them, and that made the tachometer turn on before doing an extended drive, but it still had the issue of the tachometer not going above 4500 RPM. Does anybody have an idea of what this issue could be?

had this problem on an old S10 Blazer sorry to say a new TAC fixed it I also took out the cable and went to town with some WD-40

Normally tach signal is from trailing ignition. Switch to be from the leading coil and see if it persists. It could be your trailing ignitor or coil is faulty.

Did this just start happening when it became colder?
If it's below 40F mine gets stuck and then doesn't move until it warms up. I think it's the old grease in the mechanism or something like that.

It's the grease. Now that it's getting cold out, the grease gets thick and cause the needle to stick or be sluggish. I have thie slow start issue and it's only about 50F out. Mechanical, not electrical.

Yes - the problem is only when the Tach is cold. Guess that means I only drive it in the summer months.

If you run the heater inside, it will melt the grease sufficiently to let the tach operate correctly. Run heater on Bilevel setting so you get some leg heat which will rise against the firewall and behind the dashboard instruments.

Is the tach re-greaseable? If so, what to use to ensure cold weather performance?

Too bad they're so happy in the cold weather! I swear they run so much better when the air is chilly and the motor isn't fully warmed up. Maybe it's just the nerves kicking in though :biggrin:

Best of luck with the tach! Could always try pulling it apart over winter and seeing if you can get something in there to lubricate the mechanism up.
I also have a spare gauge cluster that I'll be selling if you wanted to tinker with it.