Blk/Org wire - fuse blown..

Discussion in 'Diagnostic & Repair Tech' started by ZLR32, Jul 29, 2018.

  1. ZLR32

    ZLR32 New Member

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    Hi guys, I'm really new to the 1UZFE, and have one installed in an old 1986 Merc G-Wagen. The install was done some 10-12 years ago, not by me. So I am trying to work out what is Merc wiring and what is 1UZ wiring inside the car.

    Anyhow on to the problem. Car was driving along fine and suddenly just lost all engine power. Can crank the engine, but does not even attempt to fire.
    I found a fuse blown which feeds to a BLK/ORG wire.. that is a black wire with orange trace.
    Looking up various diagrams I see that this more or less goes to ignitors, coils, and injectors! So there is a bit to check by the look..

    My question is, before I go poking around all over the place - does anyone know if there is a 'common issue' that I should look for first? Replacing the fuse blows instantly and multi meter reads only about 25o ohms on that wire when measured to ground.

    thanks !
     
  2. gloverman

    gloverman Well-Known Member

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    I see wiring looms that fall apart and short internally quite a bit. Also rubbing from cables not being secured correctly, like the loom that runs along rhs head falling onto exhaust and burning through.

    Apply fault finding techniques for any ground situation and hopefully its not to serious. Good luck.
     
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  3. Zuffen

    Zuffen Super Moderator Staff Member

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    I've found a good way to search for a short is to replace the fuse with a low wattage light globe. This will save you a heap on replacing fuses.

    When the short is in place the bulb lights up.

    Once the bulb extinguishes you've removed the short which should tell you roughly where to look in the spaghetti bunch to pinpoint eh short and make a proper fix.
     
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  4. ZLR32

    ZLR32 New Member

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    Thanks for the replies guys. Looks like I am just going to have to work through it as you say... the idea of a short "somewhere in the wiring loom" scares me a little..
    Great idea about the bulb for helping locate it.. I've been using a multi-meter - but a constant light while I go moving, shaking and bending the loom just might show something up..

    thanks, I'll report back if and when I find something.
     
  5. Zuffen

    Zuffen Super Moderator Staff Member

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    Another option is to have the bulb on the end of long lead wires so you can see it whilst in the engine bay.
     
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  6. ZLR32

    ZLR32 New Member

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    Hello again, guys. I haven't had the time I'd like to spend on this - but anyway - I managed to get the engine to start now. Probably just by luck to be honest, whereever that short was - it seems to have just magically disappeared - I probably just moved something that has made it go away (which means it could return....).

    But!! now that it starts it has an idling problem I have not had before.
    It starts and holds high revs (I am guessing 2000-2500rpm - no tach) and after about 20 seconds, it begins to surge in a regular pattern. Falling to say 1000rpm and surging back up to 2000rpm every second or so..

    I made a youtube of it here:



    Any ideas?? unfortunately the audio doesn't show it up nearly as much as it does in person...
     
  7. ZLR32

    ZLR32 New Member

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    This is easier to hear the problem:

     
  8. Zuffen

    Zuffen Super Moderator Staff Member

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    I'd suspect the TPS needs adjusting or the throttle plate isn't closing completly.

    Both are easy to check.
     
  9. ZLR32

    ZLR32 New Member

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    Thanks for continually trying to help me with this, I really appreciate it.
    This afternoon I found that if I blocked off the air supply to the IAC valve, that it idles perfectly- so I have been googling this.
    I will dismantle and clean and report back and that - and also follow your advice to check TPS.

    Cheers!
     

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