Bouncing Speedo Pointer

[Aussie9000cse94]

Hi all, my 94 CSE Turbo Auto 9K (190K) km has now a problem with the speedo pointer. It's erratic when you drive the car.
It started to happen directly after driving over some rough roads in a country trip.

I haven't had a chance to have a look at it as yet so I was wondering if anyone has had this same/similar problem and what was the cause/fix.

(I have seached previous posts but could not find enough info.)

Your help is appreciated.

[tristan_the_trout]

Not entirely sure here of what i speak; so take this with a grain of salt.
I recall hearing that in some cars the speedo runs off a sensor on the ABS. if that got messed up, it might be throwing off your speedo.. Can anyone else back me up / dispell my theory?

sorry for the lack of certainty

Tristan

[LondonCSE]

I have a similar problem (not in my saab tho). It bounces up to about 30mph, right, then smoothes out? Basically, there are two types of speedo sensor - electric and mechanical. Not sure where the electric one is, but the mechanical one runs off the gearbox. Basically, something has worked loose and/or possibly snapped, I seem to remember there is a little plastic wheel with teeth on. Anyway, its not too bad a fix, I am no mechanic and the guy that fixed mine took about 1/2 an hour.

They tried telling me it was a gearbox failure indication, bad speedo etc. I had the speedo replaced, the cable replaced and then the sensor replaced - it worked for about a week and broke again (Rover based, under warranty at the time....). I just live with it now.

So, if its mechanical in a 9000, shouldn't be too hard to get fixed (but get a quote!), if its electric then tristan the trout is probably right....I hope this is of help (at least to diagnose the problem) but best wait for someone to shoot me down in flames before you start tearing the gearbox to pieces....!

[Aussie9000cse94]

Thanks for the advice guys.

There is no speedo cable on mine. I will have a good look at it when I get a chance.

I would assume that something had come loose or broken near the wheels as that is where most of the road shock takes place.

[Shaft]

Hey dude, check your connection to the ABS control unit under your hood. My 900 had the same problem, it was corrosion on the connection to the ABS control Unit.

Good luck.

[Aussie9000cse94]

Hi all,

thought I would post a solution to my problem.

Finally had a chance to fix this annoying problem.

I took the front wheels off (L&R) and disconnected the ABS wheel sensors.
They were a bit dirty but all looked intact, so I cleaned them with brake cleaner and put them back.

Next I checked the speedo sending unit on the transmission box and "blow me over" the damm thing was actually loose.

I cleaned around it, took it out, cleaned it some more, and put it back.

Problemo...........Solved.

Cheers

[Stefano]

The mechanical speedo was used only in the first year of the 9000, the 86. In 87 the speedo is already electric.

[Aussie9000cse94]

Damm It! (oops I swore)
Bugger! (Oh Sh*t, swore again. Oh No and again)


Yep, the problem is still here.

Will have to look at the sensor again as I remember that the actual unit in the transmission was a little losse as well. When I tightened the sensor on it, it all seemed tight, but not sure now.

A job for the weekend.

Any suggestions where else to look?

[Stefano]

I'd say that the problem must be either at the connector you already found, or, less likely, behind the speedo itself. Let alone the ABS system, it has nothing to do with the speedo.
It could be also that the plastic gear in the gearbox that drives the sensor is starting to wear out, in the case it would be necessary to pull out the tranny to replace it I hope for you it's not the case.

[Aussie9000cse94]

I hope thats it not a gearbox out.