E30 Zone

Right then, what do i look for???

I could do with having the speedo working, due to the amount of speed cameras i drive through going to/from work!!

Is it likely to be the instrument cluster? (everything else works)

Is there a connection on the autobox i should check??

Any other causes???

The speedo in my 316i is temperamental, I'm pretty sure its the connector onto the back of the instruments as a sharp slap on the dashboard brings it back to life. I'm just too lazy to pull it all apart to have a look yet.

90% of speedo not working faults are as a result of an internal break in the wire leading to the sensor on the diff, caused by vibration.
The remaining 10% are mainly caused by a duff sensor in the diff, or by cracked solder joints on the speedo unit inside the cluster.

Brian.. In your experience, how much loom needs replacing when the wire is broken?

Change the last foot, and you'll be sure.
Get a piece of wire, complete with plug, from the headlamps of a scrap E30, or, IIRC, a repair lead is available from BMW.

Check the fuses as well...

My old m10 had a duff speedo - turned out to be the fuse!

Just dragging this one up again now the car drives straight!!!

I reckon a fuse would be far too easy - any idea which one?? Surely it would affect other stuff too though??

Am i right in assuming you mean the break is most likely under the car near the diff?? If so, i'll crawl under and change it for a headlamp wire!!!

Looks like the scrap on my drive is finally coming in usefull!!

Ok, have had a little poke about under the car - although i haven't replaced the cable, i did wiggle it about and reseat the connector. There was no corrosion on the plug and the cable looked ok, but obviously i wouldn't see if it was breaking down under the insulation.

I have realised that the mile meter is still working and ticking over as i drive!!! Would this indicate the cable is ok?? Surely it must use the same signal/connection??

Everything works fine except the speedo - am i really gonna have to crawl about on the floor to replace this cable, or would it more likely be something breaking down in the dash cluster??

If the odometer is still working, then the problem is on the speedo unit itself!

Coolio - saves crawling around to change that cable - would be a piece of cake on ramps, but on the kerb it's just a pita!!

Will swap the unit tomorrow morning (if i'm not too hungover!!) and see what happens!!

In my '84 320i the speedo works only when it wants.

I noticed that it works properly when the cluster is hot (when the car is exposed to the sun, during summer for example), and sometimes for a few moments when the car is very cold.
The odometer does the same.

I think the wiring is ok...

Maybe the SI batteries?