Last night at 12:15 I started up the 83 GL and the tach was very slow to respond... it read way too low at first, then went to what I think was right, but wouldn't move for about 2 seconds after the RPM changed. Tonight it stayed at about 300 for 4 minutes or so and was reading normal by the time I'd scraped all the ice off my windows. It works fine when the car is fully warm and driving. ?????

I had a 92 Geo Storm with that exact problem... only it'd move when I turned the car on, and then stick at the highest location that I had revved it to, usually about 1500. Best guess I can do is something to do with the bushings/bearings in the tach itself. If there's any grease in there, as there should be, it might get gummy when it's cold, and gel up.

actually no grease in there, as it is jewled like a watch. i suspect the coil that makes the needle w swing is starting to go bad (and can sty like this till the wheels fall off the car). Once the coil heats up everything is fine. ONe of those learn to live with it or fix it things.

 

 

 

nipper

bad ground? between battery/body/dash? once everything warms up and expands it complete's the circuit?

My '83 does that, and has been doing that for years. In the wintertime, the tach rarely moves from zero until warmed up (sometimes longer), and in the summertime the tach works right from startup, but sticks at about 4000 sometimes. Hasn't affected performance, not really worth the effort to fix.

Most of my gauges stop responding at -40. Actually, they don't stop, but they respond extremely slowly. The tach acts fine, though.