Speedo Issues

[kiesh]

Hi there, i was on my way back from wales the other day, and my speedo starting flickering between 0 and my actual speed, then stopped working all together... is there a common fault with these (1989 e30 320i)? i checked the fuses, and theyre all ok, so i dont really know what to do now! all the other clocks work fine too..HELP!!

[kam-325i]

It might be worth cheecking the wiring from the speedo sensor on the diff.

[kiesh]

yeah i thought that, the plug is nicely located, and isnt loose at all. do these suffer from dodgey speed sensors in the diff, or any other known issue that would affect it? dont want to start rep[lacing random things to try and solve the problem that way, starts getting expensive then!

[e30-unit-soldier]

I had same problem! i bought a new sender that goes in the diff,went to replace it then found that one of the wires had come of the plug! replaced the wire and it works perfect now!
Let me know if you need the sender as i have one brand new still packed from BMW main stealers!!

[woodysjw]

Im after a sender unit for my 325 how much u looking for mate

[E30BeemerLad]

Kiesh - check the wires running to the diff sensor plug, they usually become brittle and break, either just as they enter the plug or some distance from it. You may need to scavenge a plug & decent wires from a breaker.

I am told the front foglight connecors are the same. Make sure whatever vehicle you scavenge such a part from that you get as much wire as possible, 12" at least. Then cut n splice making sure you have a good connection.

If that don't work then you may have problems with the instrument cluster, but start with the easy stuff.

[kiesh]

Ok guys thanks for the help, sorry i havent replied, ive had other problems with the car now!! (did a throtle body conversion and its idling at 3k rpm!!) the things we do for speed eh! just been guessing what speed im doing! ( i reckon 1500rpm in 5th gear is about 30...who knows!) ive checked the plug in the diff, it seemed ok, i'm thinking of jacking the back of the car up and spinning the wheels with a multi meter on the sender in the diff...any idea what sort of reading i should check for?

[kam-325i]

If its any help, my old 320i was doing 40 @ 2000Rpm in forth.

[Brianmoooore]

Unlikely to be the sensor in the diff.
Stretch the individual wires from the diff sensor, and you will probably find that one will stretch because of an internal break in the wire.
It's a very common fault, and is caused by the copper wire becoming work hardened and brittle by vibration, so replace a good length of the wire as E30BeemerLad says.

[kiesh]

Cheers Kam-325, i'll keep that in mind next time the rozzers are following me around sunderland! (its scary when youve no idea what speed your doin!) Sorry to hear about your Mayo issues... i used to have head gasket problems every week with my old 5turbo, not fun.

I just scrapped my old diff that had a sensor on it, so im hoping it isnt that, thanks for the advice on changing the cable, i'll get onto that along with the other million things that are goin wrong with it at the mo!!

[kiesh]

As suggested, turned out to be a section of knackered wire, thanks for your help once again guys!