Hi everyone - welcome to my first post!

I've just bought a nice 325i touring with a knackered speedo.  I've read loads about the problem here and on the net, but just wanted to double check I have it all right:

I check the diff sender first for visual signs on the wiring. (can I check it 'electrically'??)

Check the head for cracking on the soldered joints (I'm a bit bemused by this but presume it will be obvious once it's in front of me with my magnifying glass)

The SI lights seem to be working ok, all 5 green on just now on start-up (I used to have a 318iS, so know how they work) The MPG-ometer or whatever it's called just swings from one side to the other occasionally and I wondered if this is linked with the speedo problem or even points to a possible cause?

All help greatly appreciated, look out for my next questions - I can think of loads more already!!!

dan

All the points you mention seem to be right, but the usual is the diff sensor as you mention, not sure how to test it electrically though.

The swingometer is related to the speedo problem, once that's sorted normal service will be resumed!

The speedo sensor itself can be at fault. Mine was (and also had same symptoms as you), and cost £14.50 from BMW. To check wiring the best I can suggest (which I did) wast to put a wire across the two connectors, remove the instrument cluster and check resistance across the two wires on the plug (should be about 1ohm). Cant remember off hand what pins they are, but will look in Haynes manual at home and let you know. Was told by the dealer that its normally the sensor that goes. If you need a new speedo head, I have one here with 79,000 miles which was I was going to use for my E28 but pins wrong. Let me know if you want it.

Paul

Thanks guys, after getting a new sensor from the breakers for £2 I got home to realise that my car had different connectors anyway!

Serves me right for not checking before I left as the problem was actually only a broken wire at the dif plug......

2 butt connectors and half an hour later everything (including swingometer) is working fine!!

Hi Dan6v.

I have the exact same problem with my E30. I bought the car a

awhile ago but i've spent the last 2 months trying to fix water leaks

and get the bloody thing started!! Anyway road tested it and its

awesome apart from the speedo and MPG-ometer thing. When I

bought the car I was given a part from the guy that was supposed to

 fix it. I think its the sensor thing your talking about but I cant for the

 life of me find it on the car, so a liitle help would be very much

appreciated.

Cheers Geo1400