Speed sensor Z3 Torsen Diff

[RKB]

Hi all,

Hope you're all keeping well!

I need to resolve an issue with my Speedo.

The diff I've got my E30 is a Z3 Torsen Diff so non M, and has the smaller ring? Than a 188 E30 one so question is what speed sensor do I need and that'll work?

Cheers!

[flybynite]

The diff I've got my E30 is a Z3 Torsen Diff so non M, and has the smaller ring? Than a 188 E30 one so question is what speed sensor do I need and that'll work?

I was just planning to use the Z3 sensor that it came with but I will be using Z3 radius wheels on the back anyway. Worst case it is only around 3% out (on the safe side)

The Z3 has the same part number (62168357020) for the 3.0 and the 1.9 but the rear wheels on the 3.0 are larger radius

I may be wrong but I think the ring is larger on the Z3 because the Z3 sensors are shorter (62168355008 (E30) vs 62168357020 (Z3)

[RKB]

Thanks for the part numbers.

Do you know if the wiring is the same, so they plug in the same?

I guess I'll try both and see otherwise it's diff out job...

[flybynite]

Not sure to be honest, have not got round to doing that yet. but they have the same plug and only 2 wires so can't see it being that different.

[RKB]

Reviving this one.

Tried the E36 shorter sensor and no joy(bit obvious)

Would a Z3 rear back plate do the trick?

Any suggestions as I don't want to have to take the diff out...

Cheers

[flybynite]

Does the Z3/E36 sensor not work in the E30 back plate?

The Z3 pickup may be shorter but the sensor trigger point is further out to match the smaller wheel.

pulsegen-3.jpg

The Z3 back plate should fit, although it is a different part number they look identical.

Still don't see why the Z3 3.0i sensor will not work in the E30 back plate. Use the sensor that is meant for the diff. Are you sure it is a Z3 diff

If it is not working have you checked the wiring?

[RKB]

Does the Z3/E36 sensor not work in the E30 back plate?

Does fit perfectly.

The Z3 pickup may be shorter but the sensor trigger point is further out to match the smaller wheel.

The shorter trigger wheel and its a Torsen Diff as well makes me think it has to be a Z3 diff.

The wires have been tested.

I've had two working clusters put in and still the same, I might just test the cables again and cluster.

Pita

[flybynite]

Have you tested the sensor? I think it should make/break contact when the wheel is rotated.

Brown should be earth and the red/brown should be pulsed with wheel rotation, I would also check this at the white plug on the cluster.

is everything else working? Haven't got a blown fuse on the instruments?

If it is a torsen then AFAIK it can only be a Z3 and the 62168357020 sensor should plug in and work

Otherwise I'm at a bit of a loss TBH

[RKB]

Brown should be earth and the red/brown should be pulsed with wheel rotation, I would also check this at the white plug on the cluster.

What would you use to test? I've only had someone else test the cable at the diff end.

is everything else working? Haven't got a blown fuse on the instruments?

I'm going to change the fuses for rev and Speedo and see if that makes a difference, got to be the easiest thing to do first..

The rev counter has become intermittent.

is everything else working? Haven't got a blown fuse on the instruments?

Going to get it out and check.

[flybynite]

Brown should be earth and the red/brown should be pulsed with wheel rotation, I would also check this at the white plug on the cluster.

What would you use to test? I've only had someone else test the cable at the diff end.

I have not done this myself and can't get at either of mine to test but I would use a multimeter on continuity and it should break/make/break/make continuity as you turn the wheels. AFAIK it is a reed switch not a hall-effect sensor like the ABS sensors

I would test it at the plug and then at the cluster between the brown and brown/red wire on the white plug

is everything else working? Haven't got a blown fuse on the instruments?

I'm going to change the fuses for rev and Speedo and see if that makes a difference, got to be the easiest thing to do first..
The rev counter has become intermittent.
Going to get it out and check.

Look at fuse 10, then maybe 12 and 21, 7.5a

[RKB]

Just swapped a couple 7.5a around and the revs are back...

Noticed the mpg indicator isn't working either.

Maybe the SI batteries according to some googling...?

[flybynite]

Just swapped a couple 7.5a around and the revs are back...
Noticed the mpg indicator isn't working either.
Maybe the SI batteries according to some googling...?

If changing the fuses around did something then I might be tempted to go at them with some contact cleaner and a scotchbrite pad to make sure you have a good connection

Did you say you had another working cluster to swap?

Out of interest what size/ET are the compomotives and what size tyres are you running on them?

[RKB]

I've just grabbed some cleaner so will give that a go, got some new fuses as well.

No other cluster but I did swap my working one for another working one...

Wheels are et35 I believe 17 inch and 215 40 tyres. Will be for sale soon if you fancy them

Edit: if I can make the wheels I've bought fit...

[flybynite]

I would test the wire again first and test you get the pulse on the red/brown wire at the white plug on the cluster before doing too much more diagnosis. The speed sensor wires are known for getting brittle and breaking.

Probably got too many wheels already considering the car is not on the road yet, curious what size you managed to fit. What width are the wheels? are you using any spacers?

[RKB]

Does the car need to be on and wheels turning in order to check the wire?

17x8 et35 no spacers.

Going 16x8 et23 soon depending on fitment, I know they clear the brakes and strut.

Not sure on tyre sizes yet.

[flybynite]

As far as I can work out it is earth going to the sensor and pulsed earth going back. Check between the Brown and Brown/red for pulsing continuity as you turn the wheel. First at the sensor, then at the cluster.

Is all I would do is jack the car up (in neutral) and spin the wheel by hand to turn the segmented wheel. AFAICR it turns with the crown wheel so make sure you are turning the prop. You will only need to turn it half a turn or so

Whether you need one or both wheels up depends on if you have a working LSD.

[RKB]

Right so I've checked both the sensor at the diff and the wiring at the cluster both returned back with a signal.

Replaced all 7.5a fuses which I don't think needed changing.

So it narrows it all down to the cluster.

What can I check here?

I've had it apart but can't see anything really to fault.

[flybynite]

Bit beyond me really, never had need to have a cluster apart.

I would have a search through some old threads done by others with the same problem like this one.....

viewtopic.php?f=2&t=279606&p=2965358&hi ... r#p2965358

[Brianmoooore]

So it narrows it all down to the cluster.

What can I check here?

Open it up (all the screws around the edge on the back), then remove the screws on the back, behind the speedo, and pull the speedo assembly out.
There are four pins for the electrical connections to it, which fit into a socket on the main circuit board.
Check the soldering of the pins on the speedo's circuit board, as these can crack, causing problems.
Might also be worth checking the soldering of the blue and white sockets to the main board. These are not a weak point as such, but can be damaged if some muppet in the past doesn't realise how to release the plugs when removing the cluster.

[RKB]

IMG_20200723_191734.jpg

Cant see any breaks?

[flybynite]

Looks like someone has been there before and re-flowed some of the joints. Really hard to tell from the photo but couple of them look like there might be a gap between the solder and the pin, re-flowing not done that well.

IMG_20200723_191734.jpg

Best guess from me anyway

[RKB]

There is a little gap in both of those and the two lower ones.

I'll get some solder on them although it'll look like a child's been at it!

[flybynite]

There is a little gap in both of those and the two lower ones.

I'll get some solder on them although it'll look like a child's been at it!

If it was me I would take off most of the solder that is around those dodgy looking ones with a de-soldering tool (solder sucker)

then put a tiny bit of flux on the pin track and solder with fresh

[RKB]

There is a little gap in both of those and the two lower ones.

I'll get some solder on them although it'll look like a child's been at it!

If it was me I would take off most of the solder that is around those dodgy looking ones with a de-soldering tool (solder sucker)

then put a tiny bit of flux on the pin track and solder with fresh

Finally managed to sort it with the above!

What it means to have a Speedo and not to use Waze!!

[Brianmoooore]

Looks like someone has been there before and re-flowed some of the joints. Really hard to tell from the photo but couple of them look like there might be a gap between the solder and the pin, re-flowing not done that well.


IMG_20200723_191734.jpg


Best guess from me anyway

You, sir, have bloody good eyesight!
As with many faults, the solution turns out to be something very simple, with zero cost.

[RKB]

I won't say how long it's not been working for!

Did need a multimeter and soldering iron but that's nothing in comparison to having it shipped out for repair or a new cluster.

[flybynite]

You, sir, have bloody good eyesight!
As with many faults, the solution turns out to be something very simple, with zero cost.

Too many years of the solution staring me in the face has taught me to look at it better!

Finally managed to sort it with the above!
What it means to have a Speedo and not to use Waze!!

Glad you got there in the end

No excuses for getting done by plod for speeding now

[RKB]

The cluster strikes again...

The odometer has stopped working and the mpg hasn't worked at all.

Anyone have any ideas to why this could be?

[Brianmoooore]

I'm assuming the speedo. is still working? Check the soldered connections to the stepper motor that drives the odometer gears, and check to see if it is turning when the car is moving. The gears themselves are known to fail in hot climates, becoming soft and jelly like.
The MPG gauge in the tacho. housing has most of its circuitry on the SI board, although it takes a speed signal from the speedo. board. A long time ago, while investigating a MPG gauge failure, I found a burnt resistor on the speedo board , and a transistor on the SI board which had split in half. At the time, clusters were cheap, so at that point the whole lot was binned, and the investigation taken no further.
Is the MPG gauge completely dead, or does it move from one extreme to the other?

[RKB]

The speedometer is still working and oddly the tach has stopped as well, which initially it was the think that always worked.

Mpg moved randomly on my drive yesterday, could it just be dead SI batteries as well?.

Will take the cluster out again to check today.