Odometer not working, gears are good

[andre75]

I recently bought a 1993 E30 325i convertible. The odometer doesn't work. It is a Motometer type.
Armed with the combined knowledge of the internet, i confidently ordered gears and set out to repair it, but when I had removed it, I saw that someone had already replaced all the gears.
Now I am not so confident anymore that I can find out what is wrong. I turned the gears by hand and the odometer does increment but it didn't work in the car.

The connectors were in the usual places, but I am having a hard time figuring out the connectors for the green plug. I have had two plugs on it, unlike the video i saw for the VDO kind that "only" had one (see picture 1 below).

I am wondering if there is a way I can test the instrument cluster outside of the car and see if the gears spin when proper electrical signals are present and then go on to test the wiring harness to see if the proper signals exist. The latter will be much harder as the car may need to be in motion to record signals for odometer, but maybe i can test continuity.

In any case, I am wondering if the folks on this forum could provide me with direction of things to examine next.

Thanks!

A.

[superj]

If I remember right, that green plug is cruise control or something not needed for the odometer. Are the gear teeth all lined up properly? Sometimes people push one on to far and they no longer align, like one of the small ones under the top big one.

It's been many many years but I remember it always being one of the small gears that people would mess up aligning so take that apart and recheck all of them. Google should find you some instructions for replacing the gears

[andre75]

If I remember right, that green plug is cruise control or something not needed for the odometer. Are the gear teeth all lined up properly? Sometimes people push one on to far and they no longer align, like one of the small ones under the top big one.

It's been many many years but I remember it always being one of the small gears that people would mess up aligning so take that apart and recheck all of them. Google should find you some instructions for replacing the gears

Thanks for your reply. I have checked the gears and they seem to be done ok. I even removed and replaced them again. When I turn the small one from the drive, the odometer updates so I doubt it has anything to do with the gears.
Current theory is that the motor turning the little gear is out for some reason. To that effect my plan will be to get a signal generator and hook up the speedo to see if the gears turn or not.
According to this information:
https://www.r3vlimited.com/board/for...tach-fuel-temp
there is only one input signal (31b). Thus since the speedo works and the odo doesn't i can at least narrow it down to the instrument itself which is already a big plus (not looking forward to fixing broken wiring harness).

A.

[82eye]

Thanks for your reply. I have checked the gears and they seem to be done ok. I even removed and replaced them again. When I turn the small one from the drive, the odometer updates so I doubt it has anything to do with the gears.
Current theory is that the motor turning the little gear is out for some reason. To that effect my plan will be to get a signal generator and hook up the speedo to see if the gears turn or not.
According to this information:
https://www.r3vlimited.com/board/for...tach-fuel-temp
there is only one input signal (31b). Thus since the speedo works and the odo doesn't i can at least narrow it down to the instrument itself which is already a big plus (not looking forward to fixing broken wiring harness).

A.

if you need to send it away for fixing bavrest is a small based home electronics biz that specializes in bmw cluster repair. pretty sure they're e30 centric too. that's where mine is going when i need.

not saying you can't diy a fix. just an option.

[andre75]

if you need to send it away for fixing bavrest is a small based home electronics biz that specializes in bmw cluster repair. pretty sure they're e30 centric too. that's where mine is going when i need.

not saying you can't diy a fix. just an option.

Nice. Thanks for the tip.

[andre75]

After some idle time getting the correct signal generator I set it up and ran the Speedo on my desk for a bit:
https://youtu.be/w-Nlu6JV_50
As you can see I can control the speed easily, but the gears for the odometer are not spinning.
I pulled the first large gear to see if the motor was spinning on its own, and what do you know it is:
https://youtu.be/XfNvkedO-bI

It is kind of hard to tell from the preliminary test if the motor shaft is turning and the small wheel is slipping or if the resistance on the large wheels is too much for the motor torque to overcome. I was thinking of gluing the small wheel in with superglue. Thoughts on that?

Edit: I marked the shaft and can see that it doesn't turn when the wheels are in. The gears turn over pretty hard. I will try installing the new set I have and might have to take the odometer itself apart if the torque required is still too high.

Edit2: replaced the gears with a new set i had ordered and the thing works perfectly now. what do you know, the person before me had ordered inferior parts

A.

[82eye]

nice fix.

[nhep23]

After some idle time getting the correct signal generator I set it up and ran the Speedo on my desk for a bit:
https://youtu.be/w-Nlu6JV_50
As you can see I can control the speed easily, but the gears for the odometer are not spinning.
I pulled the first large gear to see if the motor was spinning on its own, and what do you know it is:
https://youtu.be/XfNvkedO-bI

It is kind of hard to tell from the preliminary test if the motor shaft is turning and the small wheel is slipping or if the resistance on the large wheels is too much for the motor torque to overcome. I was thinking of gluing the small wheel in with superglue. Thoughts on that?

Edit: I marked the shaft and can see that it doesn't turn when the wheels are in. The gears turn over pretty hard. I will try installing the new set I have and might have to take the odometer itself apart if the torque required is still too high.

Edit2: replaced the gears with a new set i had ordered and the thing works perfectly now. what do you know, the person before me had ordered inferior parts

A.

Just so I know what not to do. My odometer just stopped working, I ordered a set of gears from Garagistic and want to know where you ordered your gears from?
I haven't taken it apart yet.

[nick325xit 5spd]

What likely happened is that someone missed a spacer. I had that issue in a cluster that I got. One of the gears didn't mesh properly.

[richardodn]

The connectors were in the usual places, but I am having a hard time figuring out the connectors for the green plug. I have had two plugs on it, unlike the video i saw for the VDO kind that "only" had one (see picture 1 below).

A quick follow up on one of your initial questions. Those 3 positions along the side where 2 are filled in your picture are speed output signal. All 3 are identical.