Thread: Wobbly speedo

Originally Posted by tangiers

My speedo on my SIII (Holden 202 Red Engine) fluctuates by as much as 30-40km when driving. The odometer works fine.

I have had the speedo cable replaced but it still does the same thing (in fact, it seemed to get worse).

I'm told a new speedo costs $380(!). I'm sourcing a second-hand one but I am worried that the problem may still be with the cable (I've read stories on the internet of dud cables and all reports of wobbly speedos blame the cable).

I don't want to spend the money getting a new speedo and find I still have a problem.

Has anyone else had a speedo that didn't work regardless of the new cable?

Is there any other remedy other than replacing it? I read somewhere about a voltage regulator being a possible cause?

It doesn't sound like the voltage stabiliser. It sounds like a poor magnet in the gauge or the speedo drive slipping. You could take off your rear tailshaft at the back of the gearbox and ensure the output nut on the gearbox is torqued up correctly, it clamps the speedo drive and if it is loose it will slip. Mind you I'm definately not an expert. If you're in WA, I have a few spare speedos.

Another possibility is a worn out output where the cable connects into on the side of the gearbox. This happened to one of mine http://www.aulro.com/afvb/series-3/7...ml#post1105665

ooh, I'll take you up on the offer of speedos ....and yes, I do mean the car part.

My SIII is a shocker when it comes to speedo bounce ...oh the puns are endless.

Originally Posted by TJWA

It sounds like a poor magnet in the gauge

If oil works it's way up the cable, it can get into the speedo head & cause a problem like this.

Also check that the cable is routed nice & smoothly too.

It is almost certainly the drive slipping. Follow TJWA's advice. Disconnect the front of the rear prop shaft and tighten the big nut.

John

Thanks for the tips. I'll have a look at the weekend and see if I can fix it.