124 engine trouble ??stumped?? - Page 3 - PeachParts Mercedes-Benz Forum

cjlipps · #31 01-02-2007, 05:23 PM

It took about 8-10K miles after the new cap and rotor for the problem to show up. It got worse over the next several hundred miles (I kept driving it-see thread). I guess it took that long for the internal arcing to degrade the function of the contacts inside the cap. I had lots of green crud around the terminals and the center post inside the cap was charred and crumbly. I bet you've found your problem. What threw me off was the different color and appearance of the new o-ring that I ordered. I now realize that it was the same dimensions as the black one and was supposed to replace, not supplement the black one.
Chuck.

land sea air · #32 01-02-2007, 10:42 PM

AHA!!! llol that does sound like the same thing, just slightly different symptoms, however there is the same green crud and the same missing tip in the center, so how much and where should i use the dilectric grease? i just got the parts tonight so i want to try to put it together over the weekend. also is there anything else i should know about how tight this should all be and that there is only one o ring? i dont want to mess this up again

cjlipps · #33 01-03-2007, 10:10 AM

Oooo, don't know about the dielectric grease. And there is, to my limited knowledge, one o-ring that goes around the base of the "backing plate" (or whatever it's called) that seals the dist. cap to the backing plate. Just get the old black o-ring out and put the new (orange?) one in it's place. Or, if you bought a new backing plate, mine had the o-ring already installed.
It's funny how our situations are so similar. And I resisted the thought that it could be the cap and rotor. I believe it was gmercoleza that pegged my problem from the beginning but only after chasing a couple of other things did I check that out. Of course, it could have been several things and I did learn a lot about the car in my quest.
Good luck.
Chuck.

land sea air · #34 01-04-2007, 07:25 PM

well i think that did it, put the cap and rotor on this morning and havent had a miss yet, it idles a little rougher than it used to but i think the plugs may be a little rough so im going to replace them again and maybe some seals as well, thanks to everyone in here whos given me advice!!

david s poole · #35 01-05-2007, 10:41 AM

just a thought,vacuum leaks are much more pronounced at idle and tend to dissapear as the revs rise.while it's true that these cars suffer from marginal ign coils as they age i think your prob could be vac leak.find indie who can perform smoke test and ask to be there when it's performed.i think you will be amazed at all the places where the smoke is coming from.

land sea air · #36 01-05-2007, 04:38 PM

possible but since it never idled rough before all this mess i think its because of carbon build up, im definately going to check that out though if i decide to keep the car thanks!