





Frank's C32 Obsidian Obsession
checked all the ignition wires and found the third wire from the back on the passenger side is loose. fixed that and started the car and the rough idle is fixed, so it was just a misfire from the ignition coil being loose. cleaned the air-filter while I'm at it as well.
will test out the alternator and battery again for the light dimming issue on start up again. Have the uptima red top for about two year only. if anything this thing should be life time warranty by the company. hope it's not the alternator giving out. looks to be a pain in the a$$ DIY. lol
02 sensor is pretty old. no issue with it tho.
engine mount was replaced under warranty few years back and I believe it was replaced with a newer engine mount design. took a look peek at it and they look as new as they can be.
oh yea, I checked the price on the control arms. the new design with the updated part number is about $420 with my hook up. I might just get the ones from the ebay with the older design for $260.
Pleased you solved the misfire. I think Glyn is right on the mark with his battery/alternator load test recommendation. Could be a faulty connection. When they quit, they’ll usually die real fast. Have it checked ASAP. Good luck.
Don’t want to hear of you getting stranded outside the gentlemen’s club after midnight.


Pleased you solved the misfire. I think Glyn is right on the mark with his battery/alternator load test recommendation. Could be a faulty connection. When they quit, they’ll usually die real fast. Have it checked ASAP. Good luck.
Don’t want to hear of you getting stranded outside the gentlemen’s club after midnight.




btw, i'm looking at 02 sensors. can you post the exhaust diagram for me? need to know if this 0015405017 is the right part number. also there are lots of them for cheap on ebay, but all seems require you to splice wires. one with oem part number are around $60 each.

i also sent the ebay control arm guy a email regarding some questions. would it make a whole lot of difference who makes these control arms? on http://www.rmeuropean.com/search.asp...ord=2038300918 parts came out to have two manufacturer for upper. one is LEMFOERDER and the other is KARLYN and a whopping 3 manufacturer for the lower.
Last edited by FrankW; May 21, 2009 at 05:04 AM.
The Best of Mercedes & AMG

btw, i'm looking at 02 sensors. can you post the exhaust diagram for me? need to know if this 0015405017 is the right part number. also there are lots of them for cheap on ebay, but all seems require you to splice wires. one with oem part number are around $60 each.

i also sent the ebay control arm guy a email regarding some questions. would it make a whole lot of difference who makes these control arms? on http://www.rmeuropean.com/search.asp...ord=2038300918 parts came out to have two manufacturer for upper. one is LEMFOERDER and the other is KARLYN and a whopping 3 manufacturer for the lower.
Here are the O2 sensor part numbers I have for the C32 - note diff upstream left & right & diff downstream. Please use genuine heated sensors - no generics. Just get the proper ones at the right price or you will forever have ****.
300 0015400717 001 L OXYGEN SENSOR LEFT,UPSTREAM CATALYTIC CONVERTER
300 0015408717 001 R OXYGEN SENSOR LEFT,UPSTREAM CATALYTIC CONVERTER
300 0015405017 001 OXYGEN SENSOR RIGHT,UPSTREAM CATALYTIC CONVERTER
300 0015404617 001 OXYGEN SENSOR LEFT,DOWNSTREAM CATALYTIC CONVERTER
300 0015404617 001 OXYGEN SENSOR RIGHT,DOWNSTREAM CATALYTIC CONVERTER

Curse this text editor. Let me know if you can't make sense of the O2 sensors. Those part numbers have an "A" ahead of them. Good luck, Let me know how they improve driveability.
Last edited by Glyn M Ruck; May 21, 2009 at 02:20 PM.




-checked the iginition wires on #4 and went
why is B plug wire has room to be wiggled when it's tight clipped to the plug.-removed the coil pack, wires, and found the B plug "loose" with 3/4 to 1 turn away from being tight. tightened it and re-installed the wires and coil. restart the car. idle still rough.
-removed coil pack, wires, and decide to take out the plugs to check. found oil leaked out all over the B plug. cleaned and did a visual check the plug "seems" ok. re-installed everything. start the car...idle still rough.
-called John/splinter for some advise and decided to test out the coil pack, but swapping the #4 coil with my sister's CLK320's coil pack. the coil works fine on the CLK's m112. installed the clk's coil along with wires onto the m112k and rough idle continues, but not as bad.
---leads me to think the plug is cooked even tho visually it seemed ok. will buy a couple new plugs tomorrow to test it out.
another question which me and john are not sure about is that IF the CEL is not reset even with the plugs, wires, and coil pack are now working properly, would the ECU be still compensating for #4 and somehow not allowing #4 to fire normally until that code is cleared? I know it's pretty far fetched, but still plausible.
Last edited by FrankW; Jun 25, 2009 at 07:23 AM.

Clear the damn code just to make sure that ECU brain fade is not shutting down that injector. Ignition on/off reboot should do it but who knows?????? - you also say smells of unburnt fuel so injector unlikely shut down.
If all that fails - compression test - leakdown test - possible burnt valve but you would feel that popping down the exhaust - hand over tailpipe. With misfire this could be confusing.
Where did the oil come from?? Any idea why plug was loose or just an oversight?
Last edited by Glyn M Ruck; Jun 25, 2009 at 08:58 AM.




went and bought couple NGK iridium plugs. They didn't have the OE laser iridium, so I bought the cheaper iridium IX for the time being.
after installing the new plugs the rough idle is gone, but verdict will be out after driving etc later today.
also looked at the denso I took out again. the tip on the plug was fine, but the rest was burnt compare to the one that wasn't loose. I found the loose plug also on the contact end was bent. maybe this was the culprit?
smelled the exhaust also, no excess fuel smell.
Last edited by FrankW; Jun 25, 2009 at 04:49 PM.






took it out for a spin. still vibrate like crap. vibration at idle is tolerable, but when i'm in Drive holding the brakes if I ease off the brake the whole car vibrates. It isn't a random vibration either. It definitely has a rhythm to it.
The exhaust still emitting a more notable pulsating sound that wasn't there before. The back and forth vibration when i let off the brakes and let it coast forward has the same pulse as the exhaust note OR it feels that way.
could a bad primary catalytic converter cause this? OR a bad valve? the valve tick is pretty loud, but then again it has always been pretty loud. I certainly hope it isn't the valves which is the most costly to replace out of all what could be wrong.
Last edited by FrankW; Jun 26, 2009 at 12:53 AM.




what to check about it tho? was there rpm surge on yours? when that happened? I didn't notice any change in rpm behavior.
Last edited by FrankW; Jun 26, 2009 at 02:24 AM.





now excuse me that i need to go to the corner and

I seriously want to unbolt the exhaust right now and see what happens. I'll have a set of LET headers I may swap on to see.



took it out for a spin. still vibrate like crap. vibration at idle is tolerable, but when i'm in Drive holding the brakes if I ease off the brake the whole car vibrates. It isn't a random vibration either. It definitely has a rhythm to it.
The exhaust still emitting a more notable pulsating sound that wasn't there before. The back and forth vibration when i let off the brakes and let it coast forward has the same pulse as the exhaust note OR it feels that way.
could a bad primary catalytic converter cause this? OR a bad valve? the valve tick is pretty loud, but then again it has always been pretty loud. I certainly hope it isn't the valves which is the most costly to replace out of all what could be wrong.
Good luck
Last edited by Glyn M Ruck; Jun 26, 2009 at 08:40 AM.




so he suggest getting performance wires that has better heat resistance. now looking to get magnecore

I really hope for your sake it's electrical. That's easy & cheap. If the nonesense persists after wires please at least do a compression test. That costs nothing and it will put your mind at rest.




yup, that's why I'm looking into magnecore. C32 crowd has run them all these years and none had report back issues.
oh yea...definitely compression test if problem persists after the wires. What is assuring right now is that the head tech at the MB shop I go to has been working on MBs for 15-16 yr. from his experience he said after the introduction of the M112 he has never needed/seen a M112 with internal damage and says that if it was the valves/valve springs the car would've been running on 5 cylinder and vibrate to whole other level. He checked out the car and said the symptom is most likely from the wires and because of any kind of headers the temp is higher vs manifold heat that the wire was designed for.

yup, that's why I'm looking into magnecore. C32 crowd has run them all these years and none had report back issues.
oh yea...definitely compression test if problem persists after the wires. What is assuring right now is that the head tech at the MB shop I go to has been working on MBs for 15-16 yr. from his experience he said after the introduction of the M112 he has never needed/seen a M112 with internal damage and says that if it was the valves/valve springs the car would've been running on 5 cylinder and vibrate to whole other level. He checked out the car and said the symptom is most likely from the wires and because of any kind of headers the temp is higher vs manifold heat that the wire was designed for.



