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528e Speedo Woes

Discussion in 'E28 (1982-1988)' started by 123779, Apr 17, 2008.

    • Member

    123779

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    Hi,

    My daughters 1984 528e has an erratic speedo. Sometimes is works, but mostly not. Can anyone tell me where to start diagnosing?

    Thanks,

    Dave

    Autohaus guest

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    Sounds like the printed circuit board and/or the batteries behind the board. I have a 1987 528e that although the speedo works, the tachometer doesn't work 90% of the time. Removal of the steering wheel is necessary and remove the cluster and check voltage of the batteries. Hope this helps.

    Chris

    87 528e
    01 525i
    03 325xi
    • Member

    az3579

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    I don't think the clearances would be all that different from an E30. In my car, you don't have to remove the steering wheel to get the cluster out. You just have to be careful in not scratching the hell out of the window.


    When my batteries AND board were bad, the fuel gauge would always register full and the tachometer would sometimes just stick or not register anything. The temp gauge was somewhat OK, but the speedometer always worked perfectly. I think the speedometer may be separate from the board. But, if this was the case, then would the service indicator lights work at all?

    I think the speedometer's functionality is separate from the SI board/batteries, but I may be wrong about that...

    Autohaus guest

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    az3579, you may be right. I failed to mention that once I had a problem with the speedo not working (ie no miles being registered) and the fault was a blown fuse. I forget which fuse it was that kept blowing, but I had the problem fixed. The service indicator lights still work on my E28, though when the tach isn't working, the green lights stay on. Had this car for almost 12 years and still haven't gotten a new SI board/batteries...........
    • Member

    az3579

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    If the fuse was bad, then I don't think his daughter's speedometer would work at all. He says that the speedometer "Sometimes is works, but mostly not."

    I would check the connections on the back to see if it's a tight fit. If it is a tight fit, clean the connections to ensure proper conductivity. While back there, might as well take the thing apart and test the voltage of the batteries if there are problems with the other gauges. Just for laughs, check it anyway even if there aren't problems with the other gauges. It might just be related and we don't know about it!
    • Member

    MGarrison

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    If you go to the effort of pulling the instrument cluster, replace all your bulbs while you have it out. I can't speak for e28's, but I've been told on e34's, to pull the cluster, you have to pull it through the top half of the steering wheel, and turn the wheel as you pull it through for the necessary clearance. Place a clean, soft, (thick?) 100% cotton towel over your steering column and through the spokes over the front of the steering wheel to protect the cluster, as it goes through w/ the clear plastic face down (all that is assuming the e34 method may work w/ the e28).

    E30 tachs notoriously fail eventually - there are these plastic gears that give up the ghost. There is a guy who makes replacement gears who was at O'fest last year.... I think his website may be odogears.com or something like that -(not checking at the moment), or google BMW odometer gear and see if you find it.

    He may also have insight into speedo problems, possibly.
    • Member

    az3579

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    I just wanted to clarify - do you mean odometer?
    • Member

    jimoreno

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    I've heard stories of people having this kind of problems and it turns out that their sender in the differential is full of water. You'll need to either lift the car or put it on ramps in order to get access to it. You'll see the plug in the top of the differential, pull it out and clean the connections. If this doesn't help it you have to check the sender itself.
    • Member

    MGarrison

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    Yes, odometer - the odo gears fail - apologies for the lack of specificity.
    • Member

    BMWCCA1

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    If you do decide you need to pull the cluster, there's no need to pull the steering wheel to remove the it on an E28. You do know the car has a telescopic steering column, right? Make sure it's fully extended. Removing the cluster requires removing the two screws at the top and tilting the cluster with the wheel in the right position. Use a towel on the column to protect the cluster "glass" from scratches. You'll need to remove several wires and connectors to pull it out. Releasing the plugs for wiring requires lifting the black plastic bale on each and pulling the colored plugs from the board. Carefully note where each bulb and single-contact plug were connected 'cause it can get a bit confusing.

    There's no better source for E28 information than MyE28.com. Lots of good folks and information there.

    tackett37 guest

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    528 speedo

    I had the same problem on my 86 535i and my 88 528e at the time ihad a parts car so i swapped the clusters ,then found out the gears in cluster sometimes break,if all else fails I have a spare cluter you can have for shipping. I live in Upper NY 30 miles from the glen.
    • Member

    az3579

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    I once took out my speedometer gauge to see how complicated it would be to replace the gear(s) and found it to look a lot more complicated than it was worth.


    Besides, I found a complete cluster on eBay for less than they wanted for the single gear! Easy fix; swap fuel gauge, speedometer, and tach, and all gauges work perfectly now. :D

    Russianblue guest

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    if re-habbing your cluster doesn't help, i would take a look at all of your power and ground connections as well. Battery to chassis AND motor to chassis.

    Furthermore, i am a big believer in what is known as the 'big three' upgrade in car stereo circles.

    Definition: the "Big Three" upgrade means improving the current capacity of three cables: 1) alternator positive to battery positive, 2) battery negative to chassis, and 3) engine ground to chassis. Some people replace the factory wiring; others add additional cables to the factory wiring.

    of these, for the 528, #1 and #2 are the most important. The stock engine grounds are pretty darn good as long as they are attached to clean, bare metal. refer to your specific year Electrical Diagram for further info. Get it here: http://www.e28planet.com/etm.php

    There is likely no direct alt to batt (+) cable right now. At least there wasn't one in my 88 SuperETA, but that model is a tad different. Add one. BIG help all around in keeping the power flowing and the battery at peak charge.
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    • Technical Service Advisor

    mooseheadm5

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    Most common causes for this that I have found:
    Accumulation of metal shavings on the sensor in the diff (may not be your problem.)
    Bad solder joint on board or speedo (the board on the actual speedometer.)
    Bad batteries in the cluster have corroded some of the circuit board traces on the board or are just bad enough to cause problems.

    Pull the cluster and inspect all the larger solder joints, especially the ones that plugs attach to. Inspect the batteries for leakage. Inspect the speedo board for bad solder joints. Or, just buy a working cluster.

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