Instrument Cluster disassembly - SI board & odometer gea

Post Thu Oct 12, 2006 5:45 am

Hello everyone!
Just started posting here - currently has a 2dr 1984 323i, M20B23 with manual tranny. First headache was the non-working odometer issue, and with the info from this forum, I managed to sort it out!
I'm enclosing some pics, in case anyone needs visual references...

This is mine (had 140k kms) already removed from the dashboard and speedo ripped out...

Mine was the Motometer version. Discovered much to my dismay upon ordering the odometer gears that there were two versions - Motometer and VDO (guess which one I paid for...

)

Post Thu Oct 12, 2006 5:49 am

Pulling out the Service Interval (SI) board gave me grief....

Battery had leaked/went boom and caused damage. The slots for the pins had blue furry gunk in them...

Post Thu Oct 12, 2006 5:58 am

Closer inspection using high powered micron-level microscope available at your local supermarket, found further bad news....

and these...

Post Thu Oct 12, 2006 6:03 am

Oh yeah, if anyone needs a visual guide to getting the cluster out, I read it here: http://www.lehrmangroup.com/rickard/318SIbattery.html

Seems my options are pretty limited (plus I don't have soldering skills) - Brian Moore, easier to buy from the dealers or try cleaning up the furry gunk?

Post Thu Oct 12, 2006 6:09 am

So...SI board inspected and probably chucked into dustbin. On to the odometer gears...

Pulling it out and seeing more blue furry gunk nearly drove me nuts...

Anywhoo...I've to remove the clear plastic cover which holds the black gear set, and remove them with the proper ones...

Closeup view...

Post Thu Oct 12, 2006 6:12 am

With the clear plastic cover off, one can see the inner workings of a devious mind...er, wrong forum

Anyway, the shafts with brown/cocoa colored stuff is rust/sludge. Cleaning them up meant the shafts (which also hold the odometer rolling numbers) could rotate freely instead of ker-lunk, ker-lick, ker-pow...

Post Thu Oct 12, 2006 6:16 am

Pulling off them black gears showed no damage...

Post Thu Oct 12, 2006 6:19 am

Carefully laid across a sterile environment for inspection (i.e. my pants)...

I suspected that previous owner used a VDO gear set in a Motometer cluster, cause them gears ain't turnin' nuthin'...

Post Thu Oct 12, 2006 6:21 am

For reference:

Motometer odometer gear replacement - 62 129 377 343

Post Thu Oct 12, 2006 9:24 am

OK, sorry for the poor pic quality. It's a free digicam that can't do macro shots...

Anyways..

You'll get to put the three replacement gears onto the shafts. It is at this point that the VDO and Motometer gears differ (the number of teeth and the diameter of one of the two large gears). I still have the spare VDO replacement gear set in my tool box, if anyone's interested.

Gears sorted, and the odometer now works flawlessly, and can be reset with the reset button. However, discovering that I got 6km per liter was an eyeopener

but after servicing the engine, got it up to 9km per liter....

Post Thu Oct 12, 2006 9:31 am

PiperZero wrote:Carefully laid across a sterile environment for inspection (i.e. my pants)...

I like that - welcome to the 'zone by the way.

Are you then not from the UK by any chance? (You can put your location in your profile if you wish)

Good luck with the clean-up.

Post Thu Oct 12, 2006 9:52 am

Orangecurry - thanks for the heads-up. This forum had been a good source of info since it's RHD (went to e30tech.com, but they are more US-centric).

I'm in Kuala Lumpur, Malaysia (GMT +8)...where the haze is making everyone cough and ask for sick leave...

Post Thu Oct 12, 2006 10:08 am

Blimey - well are you going to find it hard to find E30s in the scrapyard? Or are dealer prices ok there anyway?

Post Thu Oct 12, 2006 10:16 am

You do get some gems in the scrappies (15" BBS, etc), but you'd have to be really in-the-loop when something nice comes up. Halfcuts of E30s and E36s can be found, but as in any scrappie, it's a 50-50 affair esp for mechanical items.

Dealer prices depends on the item. Motometer gear replacement (3pcs of plastic) went for GBP16, OEM BMW gearknob was at GBP21 brand new.

Some shops sell Eibach lowering springs for GBP177, AC-1 replica rims for GBP325...

Looking at the stuff you guys get there (Alpina rims, ellipsoids, etc) - if only I could afford the shipping rates

Post Thu Oct 12, 2006 4:09 pm

Hmm, i'v been looking for info on how to get this bloody board out for a while. So i went out a got new batteries for it, then took the cluster out then got the board out (no blue furry stuff) but apparently my LEDs are missing

Any ideas where i can get hold of some?

I thought it looked like something was missing

Post Thu Oct 12, 2006 4:30 pm

Dingbat - when I read 'missing LEDs', that got me scratching me head, and quickly scrolled up to my pic..

I believe those LEDs will be lighted on the Service Interval 'screen' on the front of the instrument cluster - the bunch of green and red colored tiny squares. I've read that those light up based on how many times the ignition is switched on, and there's some calculation involved to tell when the next service is due. Plus with a wire and alligator clip, you can short out the connection at the diagnostic port (mine looks like a pacman with measles) instead of being done by the dealer.

Hmmm, long writeup and I still haven't answered your query! I couldn't find it on realoem.com, but maybe some kind soul here has access to the ETK CD, and look if that LED section can be bought?

Post Thu Oct 12, 2006 5:09 pm

Nope, absolutly nothing in there that remotely resembles and LED.

I guess as the car hasnt been serviced by BMW for quite a few years, the row of LED's has been removed at some point to turn the inspection lights off. Kinda drastic but i suppose it works.

Post Thu Oct 12, 2006 8:55 pm

thedingbat wrote:, the row of LED's has been removed at some point to turn the inspection lights off. Kinda drastic but i suppose it works.

Very common! Always worth looking for in scrapyards.

Post Thu Oct 12, 2006 9:23 pm

Post Fri Oct 13, 2006 3:09 am

Rang up the dealers and asked whether they have the SI boards in stock, but was politely told to search in the scrappies. Don't mind that (it'll be much cheaper), but the local scrappies I went to didn't want to separate the SI from the whole instrument cluster, so have to pay for the whole thing...

Figure I have to drive to the scrappies with a disassembled cluster, swap and test the boards if they work properly....Will update soon!

Post Fri Oct 13, 2006 9:26 am

If you have a choice of boards in a scrapyard, go for one which has much shorter batteries than the one in your pic.
The shorter batteries are 3V lithium non-rechargeable batteries, instead of the rechargeable (once!) NiCds on your old board. This later modified board is much more reliable than the older type.

Post Fri Oct 13, 2006 9:54 am

makes me want to replace my batteries before they leak .

think i will hang on to my spare clocks after this tread too

Post Fri Nov 03, 2006 6:48 am

Hello all!
With Brian's advice, managed to source an SI board with the shorter batteries. Had to try 4 different instrument clusters before finding the one that was OK. The new SI board solved my dead Service Interval LED problems, along with getting the temp gauge to work properly.

Notice the green PCB in the middle of the cluster (beneath the 'Check' icon)? The older version has a hole in the middle.
The other thing is the blue pins on the left side - those are totally new to me.

Sorry for the hairy legs....

Post Fri Nov 03, 2006 6:56 am

This is the old SI board with the green PCB with a hole in the middle...

I found out that I can't plug in the new SI into my existing cluster, due to the screw hole right smack in the middle of that green PCB (which powers the LEDs)...

The top is my old cluster, and notice the cylinder into which a screw is used to hold the SI tight. (The tube beneath the 'Hazard' icon)

Post Fri Nov 03, 2006 7:01 am

This is the front view of old (top) and new clusters.

The speedo is now 20kmh higher, the slots into which the SI board pin plug into are slightly different (there's a gap in the old cluster, whereas the newer one is a continous strip) and the tacho meter is different internally.

Post Fri Nov 03, 2006 7:08 am

After hooking up the SI board, pluggin everything back into the dash, and starting the ignition, I have -
Working fuel gauge
Working speedo and odometer
Working Service Interval LEDs
Dead tacho
Working temp gauge

Thus, comparing the two tachos showed this:

Left is the new tacho (which doesn't work) and the older is to the right. Notice the 2-piece assembly of the older version. There is a black pin which holds everything together.

Post Fri Nov 03, 2006 7:12 am

Here's a closeup of the black pin in the old tacho.

Post Fri Nov 03, 2006 7:21 am

This is how it looks like before pulling it apart...

And this is the top half (RPM).

This is the bottom half - the economy gauge/meter.

Post Fri Nov 03, 2006 7:26 am

Comparing the internals of the old (2-pc) tacho vs the new version:

This is the old version (top half)...

...and this is the new 1-pc version.

Post Fri Nov 03, 2006 7:33 am

I'm bummed...

Sorted out some problems (temp gauge, SI lights) but created new ones (dead tacho).

I followed Brian's advice to verify if the temp gauge was working (ground the wire to the coolant temp sensor, and the needle moved all the way to red), but I don't know where to start troubleshooting for a dead tacho. Oh yeah, the entire right halve of the instrument panel has no lights at night (i.e. only the fuel gauge and speedo gets lit up).

Couldn't swap the tachos as they are physically built differently. The old one worked fine, though.

Anyone with guidance?

Thanks a bunch folks...

P/S: this is the unknown blue interface.

Post Fri Nov 03, 2006 8:45 am

The blue interface is the socket for a coding plug without which you'll have no tacho.

The unlit right half of the cluster is just down to a single bulb which needs to be replaced - there's one for each half, accessible from the back of the cluster.

Post Fri Nov 03, 2006 11:30 am

Chris, thanks a bunch for clearing that blue interface part and I'll check out which bulb needs replacing.

The coding plug you mentioned - where can I look for it, scrapyards, dealers...?

Is there a specific type to look for (i.e. related to engine capacity, ECU, etc)...

Thanks!
piperzero

Post Fri Nov 03, 2006 12:39 pm

Coding plugs are set up for either 4 or 6 cylider engines, because of the different 'pulses per rev' for the tach.

Scrapies are a good place to look, someone knowlegeable will no doubt log on soon and tell you how much they are from the dealers.

Did you not have one in your old cluster though?

Post Mon Nov 06, 2006 12:35 am

Hi Dingbat!

My old cluster didn't have this coding plug. Was scratching my head comparing the two SI boards upon seeing that blue interface plug at the far corner

Since mine is the L-Jet ECU, would that mean only newer Motronic ones come with this coding plug?

Thus far, my two options would be
1) search for the correct 6-cylinder coding plug or
2) get my old cluster working (i.e. temp gauge and SI LEDs) again by troubleshooting the SI board traces.

Option 1 is easier once I get the details. Option 2 would be a great long-term project since I now have two instrument clusters on hand. There's a chap on e30tech who has very good descriptions of how the SI board works with the instrument cluster, so I'll try and follow his recommendations.

Post Tue Nov 07, 2006 4:29 pm

i had to do the same opperation last night, because my rev counter wasnt working, seems my batteries were ok, however some herbert had replaced the dash bulbs sometime in the past and rather cleverly replaced them with 5 watt instead of 3! melted through the orange plastic caps over the bulbs, set fire to the pcb and burnt through the meltal contacts to the rev counter!!
guess thats why it dont work,

anyone got any suggestions as to why my on bosrd computer doesnt work though?

oh and i would also like to thank chris for in directly helping me out,
cheque is in the post mate. lol