Symptoms
- during cool mornings ...
- the tacho would jump between rpm readings
- when changing gear, the rpm readings would drop in sharp staggered steps
- when cruising the rpm guage would stick at the same rpm even with minor speed changes

Potential Solution/Background Info
In this thread, someone had a similar problem and Indycam suggested:
- the movement is sticky.
- foreign matter or gummed up lube.
- new lube for the movement bearings would not hurt.
- tachometer just needs a little oil.

In this thread, it was quoted that "asked North Hollywood about cold weather and "sticky" gearing. The man said that it's all electric, at least the later tachs. Nothing to lube."

In this thread, there is some relevant info and tips.

Tacho Removal / Disassembly
Steps to remove tacho rpm guage with my car that had the non-airbag steering wheel:
1. remove horn pad
2. unbolt steering wheel & remove
3. remove top indicator surround cover
4. pull out tach guage with fingers (use spoons if stuck)
5. Disconnect wire connection
6. The black aluminium surround is crimped over the edge of the plastic. Use a screwdriver to squeeze open the aluminium around the complete circular edge. A few tips are here.
7. Remove 3 screws on back & open
8. Remove needle by turning & pulling
9. Remove 2 black screws on printed guage backing
10. Peel off the printed guage backing
11. Remove 2 screws on clear plastic plate
12. Remove clear plastic plate

Result ...
The photos below show the internals.
I could not see anything to lube.
My guess would be the spring had a little contamination and was a bit sticky, so I put the needle back on, gave it a few spins, blew some air across the spring in case there were some small particles or dust.
I wasn't sure what to do, so I reassembled and installed.
My first quick drive seemed to indicate the problem was resolved but more testing is required to confirm.

Having done it once, it is easy to pull back out, so if I should have lubed somewhere, or done something different, any tips would be appreciated!





Just a few key words in case someone is searching for this problem in the years ahead ...
rpm guage tachometer stick sticky jump jumpy tach

 

The shaft you pulled the pointer from will be running in a bearing hole .
The bearing takes a very small amount of lube .

http://www.norkro.com/store/index.ph...products_id=84

http://www.ofrei.com/page247.html

http://www.grobetusa.com/new_products/quicken.html

 

Thanks Indycam

Lucky I didn't apply a drop of motor oil!

I'll see how it goes this week, otherwise it will be a quick job to pull back out a second time.

 

Does the mount for the pointer have a slot, spline ot similar, or could you just remount it wherever you liked? My speedo has a nice linear 4mph error and I've been wondering whether I could simply relocate the pointer to make it spot on. Unlikely, I know.

 

Hmm... looking at your 'how to' reference, it looks like it could be possible.

 

For the tacho needle, there is no alignment slot/spline. It just pushes on anywhere you like. Based on the speedo link that I posted above, and the method described to remove the needle, it appears the speedo needle is similarly mounted.

I had to google some photos to try to work out where the tacho needle should be located when the engine was off. Not sure if I got it right because the car now idles slightly higher than before!

BTW for the tacho, I would definitely recommend removing the needle by twisting anti-clockwise. When you twist clockwise it seems to overstretch the spring.

 

My guess would definitely be yes - but someone else might be able to confirm.