speedos

Post Wed Apr 06, 2016 4:31 am

hi guys again my speedo in my 323i auto has shit itself so I was wondering can you put a speedo out of an 325e into a 323i? and would it work or would it be out of calabration?

Post Wed Apr 06, 2016 9:36 am

All interchangeable. Speedo counts rotations of a rear wheel, and is not intended to be accurate anyway.
The purpose of a speedo. in a car is to ensure that you do not inadvertently break any speed limits, so all indicate that you are going faster than you actually are.

Post Wed Apr 06, 2016 11:33 am

Brianmoooore wrote:All interchangeable. Speedo counts rotations of a rear wheel, and is not intended to be accurate anyway.
The purpose of a speedo. in a car is to ensure that you do not inadvertently break any speed limits, so all indicate that you are going faster than you actually are.

thanks a million!
I have checked the-
-fuse 12(fine but cleaned her up)
-diff sensor(so clean it looks brand new)
I also checked green plug and wire goes to the dash cluster and speedo and the wire had some play from the plug! could this be my problem?

Post Wed Apr 06, 2016 1:35 pm

If you disconnect the white plug from the instrument cluster, and connect a meter on its 'continuity' setting to pins 8 and 12 of the plug, it should indicate continuity and open circuit, in succession, several times for each turn of the rear wheels. Use short pieces of bare thin wire to push into the plug, and connect the meter probes to these.

By far the most common cause of an E30 speedo. not working is failure of the copper wire inside the loom leading to the diff. as a result of the copper becoming brittle with vibration from the diff.
Gently pull the individual wires near the diff., and if one of them stretches, you've found the problem. A length of the wire, complete with plug, must be replaced, not repaired.

Post Wed Apr 06, 2016 1:50 pm

Brianmoooore wrote:If you disconnect the white plug from the instrument cluster, and connect a meter on its 'continuity' setting to pins 8 and 12 of the plug, it should indicate continuity and open circuit, in succession, several times for each turn of the rear wheels. Use short pieces of bare thin wire to push into the plug, and connect the meter probes to these.

By far the most common cause of an E30 speedo. not working is failure of the copper wire inside the loom leading to the diff. as a result of the copper becoming brittle with vibration from the diff.
Gently pull the individual wires near the diff., and if one of them stretches, you've found the problem. A length of the wire, complete with plug, must be replaced, not repaired.

thanks ive had the dash cluster out heaps of times so thats piss easy to do.
how far back with that wire should I search?

Post Thu Apr 07, 2016 2:02 am

Brianmoooore wrote:If you disconnect the white plug from the instrument cluster, and connect a meter on its 'continuity' setting to pins 8 and 12 of the plug, it should indicate continuity and open circuit, in succession, several times for each turn of the rear wheels. Use short pieces of bare thin wire to push into the plug, and connect the meter probes to these.

By far the most common cause of an E30 speedo. not working is failure of the copper wire inside the loom leading to the diff. as a result of the copper becoming brittle with vibration from the diff.
Gently pull the individual wires near the diff., and if one of them stretches, you've found the problem. A length of the wire, complete with plug, must be replaced, not repaired.

I ckecked the wire on the diff and it realy stiff and hard like you were saying it should be so whats next? could it be that single green wire and plug that goes to the back of the speedo in the cluster?