How to repair your ECU ignition part 2

Discussion in 'Electronics' started by grober, Jan 20, 2013.

  1. grober

    grober MB Club Veteran

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    Now you have removed the heatsink clip you can remove the bottom cover to reveal the circuit board to desolder the transistors.

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    I should add that as Dieselman has helpfully reminded us quite frequently these ECU ignition out transistors overheat due to problems with the ignition coils or their low tension supply wiring from the ECU to the coils themselves. This is often due to thermal stress causing wiring insulation breakdown or bad connections in the ECU plug. After you repair the ECU it would be a pity if that work was wasted by the original fault causing a second failure. Have a good look at the wiring and check the coils since they are a very common failure on that engine. On 4 cylinder cars One coil fires 1 and 4 and the other 2 and 3 plugs. If there is evidence of coil failure replace it.

    Once more I should acknowledge Algorithmus contribution to this thread by the use of his pictures.

    So if you have an old VDO W124 ECU with burned out ignition control transistors and you fancy your chances with a soldering iron--------what have got to lose ???????????
     
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  2. Dieselman

    Dieselman Banned

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    I have done this job on a FIAT car and that transistor was a BU931ZT.

    In that instance, the ignition amplifier was made by Magnetti Marelli, which indicates wide use of that transistor for this application.
     
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  3. OP
    OP
    grober

    grober MB Club Veteran

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    I should have added that I tried to PM Algorithmus about this thread but since he hasn't been active on the forum since 2011 and didn't reply it seemed a shame not to include his pics on a HOW TO before they disappeared into cyberspace forever. Any comments singular omissions errors etc welcome.
    If the mods think its worth it they could maybe move it to the HOW TO section
     
    Last edited: Jan 20, 2013
  4. Dec

    Dec Hardcore MB Enthusiast

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    Is there a Part 1 somewhere, got a link?

    Dec
     
  5. OP
    OP
    grober

    grober MB Club Veteran

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    1 person likes this.
  6. kth286

    kth286 Hardcore MB Enthusiast

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    I went out with him in his car last year (or was it the previous year?).

    He was on about going to BMW car next, same as his mate.
     
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