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Thread: ECU fire, melted coil.

  1. #1
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    ECU fire, melted coil.

    Good morning to all,


    This past weekend while traveling, I had an ignition coil fail while simultaneously encountering an ECU fire on dme #1. Upon closer inspection it appears as though it started at one of the pins on the dme as the connector is melted at one point. The attached pictures tell the story. The coil only had about 3000 miles on it.

    Perhaps someone here can chime in on what would cause this to happen on an otherwise perfectly running vehicle?
    20190121_104840.jpg20190121_104837.jpg20190121_104134.jpg20190121_105925.jpg20190121_105922.jpg
    Last edited by rotomoto712; 01-21-2019 at 11:00 AM.

  2. #2
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    Wow only 3k miles, That's scary! Sorry to see this, The coils are a very important maintenance item, Should be replaced every 40 to 75K in my opinion, They are the culprit of your DME damage usually, That yellow snot looking crap usually poors out of them. FWIW i would try MSD coils next round, I haven't seen them fail yet, I'm going on 4 years with them now.
    Attached Images Attached Images
    Last edited by 8eights; 01-21-2019 at 11:52 AM.

  3. #3
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    Quote Originally Posted by 8eights View Post
    Wow only 3k miles, That's scary! Sorry to see this, The coils are a very important maintenance item, Should be replaced every 40 to 75K in my opinion, They are the culprit of your DME damage, That yellow snot looking crap usually poors out of them. FWIW i would try MSD coils next round, I haven't seen them fail yet, I'm going on 4 years with them now.
    Thanks for the info. I've already ordered a new replacement coil, but I think I may have to seriously consider the MSD coils once I replace the DME and check out the wiring harness.
    Last edited by rotomoto712; 01-21-2019 at 12:06 PM.

  4. #4
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    Just be sure not to test another DME with that bad coil, It will take out as many as you put over there.

  5. #5
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    It is difficult to say what happened first - either the coil failed and caused the FET output stage of the DME to self-destruct; or, the FET failed short-circuit (they do that) and burned the coil out.

    Whatever it was, both the coil and the DME needs to be replaced. When this happened on my 740i (which has 8 x output FET's and 8 x coils) I replaced the FET and the coil and all was good again - but your FET failure does seem to have caused quite a lot of damage to the DME:

    https://www.meeknet.co.uk/E32/ECU/Index.htm
    Last edited by Timm; 01-21-2019 at 03:14 PM.
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  6. #6
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    I installed the MSD Blaster coils 8207 a couple of months ago along with NGK platinum plugs and car is running fine. The coil wire on the car will need a 'clamp' style connector to fit the MSD primary terminal. You will need to make some adapter plates to mount the coils to OEM mounts. I owe credit to someone on here because I used his design for the adapter plates but I dont remember who it was that came up with the design.
    IMG_20190121_143152661.jpg
    IMG_20190121_143140619.jpg
    msd mounts.png

  7. #7
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    Can you make more for $$

  8. #8
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    Quote Originally Posted by 8eights View Post
    Can you make more for $$
    If I had some sophisticated equipment I would but I just used a scroll saw, files, and sander so it takes too much time making them by hand. If anyone uses the drawings in photo be sure to measure the mounting holes so that you can enlarge the drawings to the correct size.

  9. #9
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    I did pretty much the same but yours look a tad better, Good job!

  10. #10
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    Quote Originally Posted by 8eights View Post
    I did pretty much the same but yours look a tad better, Good job!
    Thanks! I printed up the drawings and then used some spray adhesive on paper to stick drawings to 3/16" alum plate. That was the easiest way for me to transfer the pattern to material without going to extra work. Just wish I could remember who came up with the original design on here.

  11. #11
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    Maybe this was the thread you speak of:

    https://www.bimmerforums.com/forum/s...&highlight=MSD
    Attached Images Attached Images

  12. #12
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    Here is a billet MSD coil mount but I called them when I needed mounts and the spacing on theirs was not close enough to fit the OEM bracket. And, there's not enough material to slot the holes to make them work.
    https://shop.speedunlimited.com/p-10...8207-coil.aspx

  13. #13
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    ^^^After reading through that thread and conducting a bit of extra research, it seems reasonable to conclude that the dme transistor is what actually killed my 3K mile coil. Is there any preventative maintenance that can be performed to mitigate the potential for this happen again in the future, i.e. DME rebuild service with newer components?

  14. #14
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    Good info from Hella with pics, more in the link:

    INTERNAL SHORT CIRCUITS
    Overheating of the coil caused by the aging process, a faulty ignition module, or a faulty output stage in the electronic control unit.

    FAULT IN THE VOLTAGE SUPPLY
    The coil charging time increases on account of the voltage supply being too low, this can lead to premature wear or overload on the ignition control unit or the output stages in the electronic control unit. This can be caused by faulty wiring or a weak battery.

    MECHANICAL DAMAGE
    Damage to the ignition cables caused by marten bites. A faulty valve cover gasket and resulting engine oil leaks can damage the insulation of plug slot coils. Both of these causes lead to sparkover, and thus premature wear.

    CONTACT FAULT
    Contact resistance in the wiring due to humidity penetrating in the primary and secondary area, also frequently caused by engine washing or the use of grit in winter.

    3 SYMPTOMS OF A FAULTY IGNITION COIL: SYMPTOMS
    •Engine does not start
    •Vehicle misfires
    •Poor acceleration or loss of power
    •Engine control unit switches to limp-home mode
    •Engine warning lamp lights up
    •Fault code is stored

    4 MEASURING THE IGNITION COIL: BASIC PRINCIPLES
    Dismantled state
    There are different ways of checking the ignition coil:
    Testing the resistance values of the coils using the ohmmeter.
    Depending on the ignition system and ignition coil design, the following reference values apply: (observe the manufacturer's specifications)

    Cylinder ignition coil (transistor ignition system)
    Primary: 0.5 Ω–2.0 Ω/Secondary: 8.0 kΩ–19.0 kΩ

    Cylinder ignition coil (electronic ignition system with map-controlled ignition)
    Primary: 0.5 Ω–2.0 Ω/Secondary: 8.0 kΩ–19.0 kΩ

    Single-spark or dual-spark ignition coil (fully electronic ignition system)
    Primary: 0.3 Ω–1.0 Ω/Secondary: 8.0 kΩ–15.0 kΩ

    PRACTICAL TIP
    Note:
    If a high-voltage diode is built into an ignition coil to suppress sparks, it is not possible to measure the resistance of the secondary coil.

    In this case, the following method is helpful:
    Connect a voltmeter in series between the secondary winding of the ignition coil and a battery. If the battery is connected in the diode's conducting direction, the voltmeter must display a voltage. After reversing the polarity of the connections in the blocking direction of the diode, no voltage must be displayed. If no voltage is indicated in either direction, it can be assumed that there is an interruption in the secondary circuit. If a voltage is indicated in both directions, the high-voltage diode is faulty

    Installed state
    The following checks can be used:
    Visual inspection
    •Check the ignition coil for mechanical damage
    •Check the housing for hairline cracks and sealant leaks.
    •Check the electrical wiring and plug connections for damage and oxidation.

    Check the electrics using a multimeter or oscilloscope
    •Check the voltage supply to the ignition coil
    •Check the triggering signal from the ignition distributor, ignition control unit, or engine control unit
    •Illustration of the high-voltage curve using an oscilloscope or ignition oscilloscope

    Testing with the diagnostic unit
    •Read out the fault memory of the ignition system or engine control
    •Read out parameters

    During all testing work on the ignition system, please note that faults established during tests with the oscilloscope are not necessarily faults caused by the electronic system; they can also be caused by a mechanical problem in the engine. This may be the case, for example, if compression is too low in one cylinder, which means the oscilloscope shows the ignition voltage for this cylinder to be lower than that of the other cylinders.

    NOTE
    Although "diagnosable engine management systems" are installed in today's vehicles, a multimeter or oscilloscope must be used when checking ignition systems. In order to interpret the displayed measuring results and figures correctly, additional employee training is usually required. One important pre-requisite for successful diagnostics is a careful visual inspection at the beginning of the troubleshooting process.

    https://www.hella.com/techworld/us/T...ion-coil-2886/
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