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Thread: Ignition coil resistors?

  1. #1
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    Default Ignition coil resistors?

    OK, guys, today I wanted to check out the spark plugs and discovered that those rubber "dildos" (I don't know the correct term so I'll just use this one ) that connect the coils with the spark plugs have different kOhm ratings?! Wtf?

    Two of my coils are original BMW (BREMI) and have 1.8k Ohm dildo attached to it, and 4 of them are Bosch which have 1k Ohm dildos. I also noticed that those parts have different part numbers. I suppose this isn't right, ay?

    I also noticed that those original BREMI coils are starting to develop some candy underneath - not much, just a few mm, but still visible. Should I swap them now before they fry my Motronic? Could this be the reason for a slightly lumpy idle and hesitation in lower rpm range?

    Btw., I suspect my valve cover gasket is leaking - I found some oil in one of the spark plug holes and the rubber dildo had oil on it so I guess it's dripping from above?
    BMW E34 528i, M52B28 + M50 manifold, Remus exhaust, ///M Parallel Spoke 18" rims

  2. #2
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    Default

    definetly fix the oil leak, that will lead to coil/dme failure.

    your dildoes are called spark plug boots, they are cheap and you should replace them all, same with the coilpacks, get all at once, save old good ones as spares or give em away on Ebay.

    when I first got my car it had the Nikasil failure miss, wasnt a nice thing. I replaced the coilpacks and plugs, then injectors and still had the proud failing Nikasil miss...finally as a last resort I got the boots to polish up the complete projest and the miss went away, expensive order of replacement.
    95 E34 530I V2.31
    ===========
    Those who make peaceful revolution impossible will make violent revolution inevitable.

    John F. Kennedy

  3. #3
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    Default

    Quote Originally Posted by 632 Regal
    definetly fix the oil leak, that will lead to coil/dme failure.

    your dildoes are called spark plug boots, they are cheap and you should replace them all, same with the coilpacks, get all at once, save old good ones as spares or give em away on Ebay.

    when I first got my car it had the Nikasil failure miss, wasnt a nice thing. I replaced the coilpacks and plugs, then injectors and still had the proud failing Nikasil miss...finally as a last resort I got the boots to polish up the complete projest and the miss went away, expensive order of replacement.
    So the oil is definitely coming from the valve cover gasket? The spark plugs were very tight, I doubt it came from below.

    Should all of those spark plugs boots be the same, or do they depend on the ignition coil (ie., do different ignition coils require different boots, especially resistance-wise)?

    Btw., what coils should I buy - Bosch, Bremi or Meyle? Bosch being the most expensive and Meyle the cheapest.
    Last edited by Interceptor; 11-05-2005 at 11:21 AM.
    BMW E34 528i, M52B28 + M50 manifold, Remus exhaust, ///M Parallel Spoke 18" rims

  4. #4
    Join Date
    Jan 2004
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    4,148

    Default The resistance values you state are correct for

    each of them , bosch is 1k ohms and bremi is 1.8k ohms
    Also bmw recommends that you only use on manufacturer of coils on the engine. Problems can occur otherwise.. Ie . all bosch or all bremi etc...
    I have had very good results with bremi, even better than bosch. I wouldn't use meyle unless i had to.




    Quote Originally Posted by Interceptor
    OK, guys, today I wanted to check out the spark plugs and discovered that those rubber "dildos" (I don't know the correct term so I'll just use this one ) that connect the coils with the spark plugs have different kOhm ratings?! Wtf?

    Two of my coils are original BMW (BREMI) and have 1.8k Ohm dildo attached to it, and 4 of them are Bosch which have 1k Ohm dildos. I also noticed that those parts have different part numbers. I suppose this isn't right, ay?

    I also noticed that those original BREMI coils are starting to develop some candy underneath - not much, just a few mm, but still visible. Should I swap them now before they fry my Motronic? Could this be the reason for a slightly lumpy idle and hesitation in lower rpm range?

    Btw., I suspect my valve cover gasket is leaking - I found some oil in one of the spark plug holes and the rubber dildo had oil on it so I guess it's dripping from above?

  5. #5
    Join Date
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    Default

    Quote Originally Posted by Bill R.
    each of them , bosch is 1k ohms and bremi is 1.8k ohms
    Also bmw recommends that you only use on manufacturer of coils on the engine. Problems can occur otherwise.. Ie . all bosch or all bremi etc...
    I have had very good results with bremi, even better than bosch. I wouldn't use meyle unless i had to.
    OK, so Bremi it is - they're even $12 cheaper a piece. Do they already come with plug boots on them? BMA online catalog has the picture of it and it's shown with the boot already installed.
    BMW E34 528i, M52B28 + M50 manifold, Remus exhaust, ///M Parallel Spoke 18" rims

  6. #6

    Default

    Then that's what you should get. As 632 said, fix the leak. If you found oil at the bottom of the plug tube you may have some seepage in to the cylinder(s) themselves. If you are coming up on plug replacement you might as well go ahead and do it now with everything else. Otheriwse if the plugs are fairly new and not nasty clean them up real good and reuse them. So while on line w/BMA get your self the valve cover gasket set, spend the extra dollars and get the bolt gaskets as well. Use a little dilectic tune up grease and wipe aoround the inside of the boot to get a nice moisture proof seal beween the boot and plug. Apply it around the lip of the coil cap where it seals around the plug tube itself as well.

  7. #7
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    Default

    Quote Originally Posted by peterllo
    Then that's what you should get. As 632 said, fix the leak. If you found oil at the bottom of the plug tube you may have some seepage in to the cylinder(s) themselves. If you are coming up on plug replacement you might as well go ahead and do it now with everything else. Otheriwse if the plugs are fairly new and not nasty clean them up real good and reuse them. So while on line w/BMA get your self the valve cover gasket set, spend the extra dollars and get the bolt gaskets as well. Use a little dilectic tune up grease and wipe aoround the inside of the boot to get a nice moisture proof seal beween the boot and plug. Apply it around the lip of the coil cap where it seals around the plug tube itself as well.
    I was planning on getting the valve cover gasket set + some intake tubes/boots. My plugs are Denso Iridium Power and are only a couple of months old so I'll just clean them and reuse them. Thanks for the advice on the dilectic grease, I didn't know that!
    BMW E34 528i, M52B28 + M50 manifold, Remus exhaust, ///M Parallel Spoke 18" rims

  8. #8
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    Wichita, KS
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    Default oil in coil packs

    The 95 540i I picked up from my dad had all 8 coil packs 50% immersed in oil. Unbelievably, the car was glass smooth when I drove it down to southern IL (350 mi.) from their place. I found it when I began to remove the valve covers to replace the gaskets and redo the original silver paint coating, which had been flaking off over time. The car has not been run since cleaning everything out, as I am putting in a new clutch kit and flywheel, servicing the manual tranny, replacing all the original exhaust hangers and hardware, along with doing general housekeeping under the car from a leaking power steering line out of the reservoir (damn oetiker clamps). Aside from 4 of the 9 flywheel T55 bolts rounding out, this is a really nice car to work on, aside from the obvious fun of driving part. One annoying thing though is why they insisted on using dissimilar metals for things like the heat shield retainers. Obviously these are gonna rust like stink... CAM

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