I have a 1986 190E 2.3 8 Valve M102. I have Bosch Plug wires and all Bosch for the ignition system as it is supposed to be. I tested all four plug wires, only a few months old, and got readings of 1.4Kohm on each except one! I replaced the 1 with a wire that I had put a new connector on before and that wire was 1 KOhm as the spec states it should be. I tested all the other old ones I still have and they were all 1.4 K as well, they are all marked 1 KOhm on the plug end. Now my question is why are all the Boxed ones at a higher rating than the one I replaced the end on? Do I need to go out and buy three more ends and hope they all test to 1 Kohm when I put them on? I am at a loss here as to why all test high and the same value and the one I replaced the end on tests to where it should be? Could this be what causes my shaky idle? Motor mounts have been replaced as well as all Idle related parts cleaned. Mixture is also an issue as it wanders after set so I ordered a new Hex Key set for it. Not sure why the hex key would cause it to wander as the spring still seems good in it and it does come up after set but I ordered it anyhow. Any ideas as to why I can see my hood shaking and the idle seems to stay steady but still cause roughness I am open to try other things....

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

verify your spark plugs are the original model as ORIGINALLY specified for your car and as specified in your owners manual. Mercedes dealerships or the local parts store often have substitutions for part numbers for the plugs. They get the model or the resistance wrong and MB will substitute an inferior and incorrect plug to simplify dealership inventory while wreaking havoc on these older cars. This was the case for my 1984 380sl by substituting the w9dc0 for the correct w9dc or the local parts store incorrectly specifying, in their parts feeds, plug model numbers.

They are the correct ones and copper. The plug wires were measured from end to end with no plugs in them.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

Jamie:

One of the pro techs who participates here once commented on the variation in quality of the Bosch line as a whole. It seems they make a Grade A, Grade B; Grade C and this applies to what you might purchase from an MB dealer as well. The Bosch stuff that Auto Zone carries is in my mind, Grade C.

They're hard to find, but it's my impression from searching here, that Beru makes much better plug wires than Bosch.

Makes sense since I bought the one end at the dealer and the wires from European Automotive. Although I did just purchase 3 new ends from European Automotive so I am keeping my fingers crossed that they read properly. Since they are just the ends not the whole wire. Only 30 bucks so if all else fails then Beru it is.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....