Tachometer error after full cluster restoration

Post here for mechanical and engine topics such as fuel issues, transmission problems, rough idle, exhaust, electrical issues, etc

Moderators: GRNSHRK, ron, bfons

Post Reply
mark22
Posts: 32
Joined: Mon Dec 19, 2011 6:58 pm
Location: Dallas, TX

Tachometer error after full cluster restoration

Post by mark22 »

Hello to all and thanks for the advice in advance. I just had my E24 M6 cluster completely overhauled (tach was completely inoperative)by Bavarian Restoration, and while it looks beautiful, the tachometer is reading about 500 RPM lower than it did before and is not a fluid when climbing through the RPM range. It is better than it was (not working at all), but it still is not reading properly. As instructed, I changed all the fuses with new ones that pertain to the cluster, and still, no change. I have also reset the Service indicator lights using the reset tool by plugging it in to the port under the hood.

After reading, I have really gotten confused with everything that may be related which included DME computer, "voltage stacking" and also the possibility of weak batteries in the board, even though these were reportedly replaced. I was also told driving the car may help correct it. Any thoughts?

Also, I found a light that was behind the cluster that is always illuminated and I cannot determine where it goes. It is one of three bulbs that come out of the wiring harness and is fed by two wires, one Green wire, one combination Black/White wire. The only conceivable place I see it going is to ABS or the check engine light. I looked up the schematics on the electrical diagram, and was unable to locate it. The other two bulbs fit in the bulb receptacles that illuminate the headlight and fog light symbols on the plastic panel below the cluster when the headlight switch is turned on.

Any help would be very much appreciated. Thanks again.
1987 M6 pre 6/87
baders
Platinum Member
Platinum Member
Posts: 1084
Joined: Sun Nov 23, 2014 7:38 am
Location: Perth Australia

Re: Tachometer error after full cluster restoration

Post by baders »

It helps if you put your car model/year in your signature.
1986 635csi LOCUTUS / Arktis Blau Metallic / Pearl Beige / S38B36/ Close ratio dogleg 5sp
2002 E46 M3 / Topaz Blau Metallic / Black Nappa / 6 speed SMG software tuned / Bilstein PSS10 Coilovers / CMP RACP reinforcement
baders
Platinum Member
Platinum Member
Posts: 1084
Joined: Sun Nov 23, 2014 7:38 am
Location: Perth Australia

Re: Tachometer error after full cluster restoration

Post by baders »

Did they install the same (or correct) instrument coding plug after the overhaul ? You can see the coding plug here in this Programa sheet;

http://www.programainc.com/info/094/Doc ... ch-tip.pdf
1986 635csi LOCUTUS / Arktis Blau Metallic / Pearl Beige / S38B36/ Close ratio dogleg 5sp
2002 E46 M3 / Topaz Blau Metallic / Black Nappa / 6 speed SMG software tuned / Bilstein PSS10 Coilovers / CMP RACP reinforcement
mark22
Posts: 32
Joined: Mon Dec 19, 2011 6:58 pm
Location: Dallas, TX

Re: Tachometer error after full cluster restoration

Post by mark22 »

It is a 1987 pre 6/87 M6. The coding plug was in it's proper place. Is it possible it is faulty or got switched? Any ideas on where to confirm it is the rigt one or obtain a new one?
1987 M6 pre 6/87
baders
Platinum Member
Platinum Member
Posts: 1084
Joined: Sun Nov 23, 2014 7:38 am
Location: Perth Australia

Re: Tachometer error after full cluster restoration

Post by baders »

It is possible that they have installed the wrong coding plug. Would have thought they would test all functions before taking your $ though.

RealOEM shows this part number for the pre 6/87 M6;

http://www.realoem.com/bmw/enUS/part?id ... 2111377664
1986 635csi LOCUTUS / Arktis Blau Metallic / Pearl Beige / S38B36/ Close ratio dogleg 5sp
2002 E46 M3 / Topaz Blau Metallic / Black Nappa / 6 speed SMG software tuned / Bilstein PSS10 Coilovers / CMP RACP reinforcement
mark22
Posts: 32
Joined: Mon Dec 19, 2011 6:58 pm
Location: Dallas, TX

Re: Tachometer error after full cluster restoration

Post by mark22 »

Yes, I agree with you. The thought of removing the cluster again and shipping it back to California does not sound appealing. I ordered a coding plug from BMW today and report back once it arrives. Nothing like starting a fire with 100 dollar bills.
1987 M6 pre 6/87
GazM3
Posts: 1791
Joined: Wed Oct 26, 2011 12:55 pm
Location: Melbourne, Australia

Re: Tachometer error after full cluster restoration

Post by GazM3 »

I needed up installing a Dakota digital tacho adjuster as mine was doing same. I think this phenomenon can be caused by the check control oil reset thingy.

Btw it fixed the lower reading tacho perfectly.
BMW’s
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody

OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
Post Reply