guys

I have been recently having trouble with my speedo needle
its OK from cold but as the car warms up esp on a warm day,the needle has a bad case of the St Vitus dance between zero kph and about 50 kph and starts doing 270s
after that at a steady 50 kph upwards,its quite stable
the speedo has about 24k kms from a NHS rebuild about 8 1/2 years ago
my mechanic has looked at it and can't see anything obviously wrong with the cable and seems to think its a design fault somewhere
does this sound like the cable or the gauge ?
its becoming a bit alarming to see the needle flicker too much

over to the experts
TIA
Dennis

I think the cable is a more likely suspect than the gauge. It's also cheaper to replace generally than the gauge is, so that's a bit convenient.

I'd suggest testing, but it's hard to note the speed of revolution of the cable end while you're driving. Even having someone else watching it wouldn't make it easy, since it's hard to judge more than "fast".

If you have access to another speedometer, I'd suggest swapping that in and seeing if it does the same thing. The 911 speedo will work for testing; it may not show the speed accurately but it will show the "dance" if the cable is truly at fault.

--DD

When this happened to me, it eventually started squealing and then finally the cable broke. I'd go with a failing/bad/dry cable. You could try pulling the gauge out and shooting/dripping some lube into the cable and see if that helps.

double post

My speedometer did the same thing. It was the cable, not the speedometer. Make sure the cable housing has no sharp curves or bends in it, and that the cable has plenty of lubricant. I discovered that my cable was very sensitive as to how much it was bending coming out of the central transmission tunnel and up to the dash and speedometer. If it wasn't "just right", the speedometer needle would jump all over the place at lower speeds.

thanks All

I have a minor service due soon and I will get the cable checked out
thanks again

cheers
Dennis

I did not know there was anything like “minor service” appointments fir a 40 year old 914.

I would agree that it is the speedo cable. They are cheap, so I replace them when the speedo starts twitching. The factory six is about due to have it replaced.

Has anybody ever found a solution to this jitterbug speedo needle issue? My car had a new speedo cable, but it didn’t fix the jitters.

Check the cable routing. If it is bent too tightly, sometimes it results in this behavior.

The gauge or the angle drive on the transmission end of the cable are also possible suspects. Harder to check, though. If you have access to another speedo, you can at least swap that and see if the behavior changes.

--DD