E30 M3 faulty speedo help...

[busterm3e30]

Hi,
I have 1990 E30 M3 2.3 215bhp version. The car has a faulty speedo. I have tried quite a few fixes but none of them have worked. I think I am at the stage now where I will just have to buy a new speedo. I will list what I have done to try solve the issue. If anyone has any other suggestions which might work I would be very grateful.

Initially the speedo would flicker and work after the car had been running for 20mins or so then it would work fine for the rest of the journey. The mileage and trip do not change when the speedo isnt working.

-Firstly I replaced the speed sensor on the diff as well as the 1st foot or so of wire from the sensor. I believe this is a common issue. This made no difference.

-After that I removed the cluster took the cluster apart making sure the everything looked ok. Checked the connections etc everything looked mint. Put it back together nothing improved.

-Next step was I took the cluster apart again and warmed all the circuit boards with a heat gun. Then I reassembled the cluster, refitted it and everything worked great. The speedo worked straight away. The it stopped working with no flickering, the radio stopped working with it and the illumination for the computer went out as well. And It kept blowing no.12 fuse

-Then a process of a elimination began disconnecting the radio seeing if the fuse blew etc .Then I found that disconnecting an amplifier for the radio fixed the radio issue and the computer. And the fuse blowing.

-After this the speedo has not moved at all no flickering. So I got the soldering iron out and when over some of the joints which I had heard about/read about on the forum. This made no difference and the speedo needle dropped to a lower position that it normally sat at.

-I have also check the si batterys with a multimeter and there reading 3.2v pretty good for 24 year old batteries!

This is the point Im at now ill attach some images of the speedo position its in. The rest of the cluster works great.

[busterm3e30]

sorry cant get pics to upload Ive put them in my photobucket here are the links:

http://s965.photobucket.com/user/jmwall ... 6.jpg.html

http://s965.photobucket.com/user/jmwall ... 9.jpg.html

[busterm3e30]

Fixed pics, you need to use the direct link provided in photobucket and wrap in tags.

Check this thread, http://www.e30zone.net/modules.php?name ... c&t=242685 and do the check with the multimeter to see if you are getting the pulse at the cluster plug.

Thanks for sorting the photos willnz. Forgot to mention this in the blurb which is quite important but ive tried another cluster and the speedo worked fine. So guessing there will be a pulse. Just for reference is the Speedo cluster plug the white plug between the fuel gauge and the speedo.
cheers

[bigbird76]

Well I did this job on my M3 about 6 weeks ago..

I had the exact same symptoms as you and replaced the diff sensor and about 400mm of wiring from the diff with no joy..

Anyway I removed the speedo from the clocks cluster and re-flowed all the solder on the small clock board. Even though all of the joints looked good one of them must of been dry because it worked for me heating the board up with a heat gun will not do it, You need a decent soldering iron and add some new solder as you go along.

Read this guide
http://www.unofficialbmw.com/speedo/speedo.htm

It worked for me..

Cheers

Leigh