Mu9enx

Check my car too, lol.

splinter

Late to this one; been offline for two days.

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.

Glyn M Ruck

O2 sensors have a design life of about 80,000 miles before they go out of spec & their cycle times become too long. Symptom is stuttering on pick up when you initially load the engine.

TemjinX2

i remember i changed my 02 sensor at 175k on my integra even though i didnt have a ceil. It actually improved my mpg by 2mpg.

Glyn M Ruck

Yeah Mike - half the cars on the road run around with O2 sensors that are out of spec.

FrankW

good idea glyn. I'll look into that. won't hurt to replace'em anyway.

Glyn M Ruck

splinter is also pretty much on the mark. Battery & alternator might be just fine - could be connections. Check the earth straps. We don't want the car to be trying to achieve earth via gearbox bearings etc due to a shot earth strap. This does bearings & the like no good.

FrankW

will check it out.

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.

Glyn M Ruck

Frank - I dont think it matters what manufacturer's arms you get - just make sure you get the new bushes.

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.

FrankW

got a CEL today on the way to pick up new exhaust. read it with code scanner and yup, P0304 misfire code. The car idles rough and exhaust smells like un-burn fuel. talked to MJ, Splinter, and a local MB tech on some idea and possible causes.

-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.

Glyn M Ruck

Frank - uncleared code should make no difference to proper behavior of Cyl 4. Put 2 new plugs on that cyl with your sister's coil pack & wires. See what happens.

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?

FrankW

no idea why the plug would be loose. might be from taking on and off the wires from dealing with the header issue.

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.

Glyn M Ruck

I suspect you have licked it - hope so.

FrankW

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.

nlpamg

the letting off the brake and vibrate or going gently on the brake and vibrate sounds kind of like my problem with the TB. have you checked yours?

FrankW

TB was replaced with a 113 part # not long ago, so i didn't check that...maybe i should.

what to check about it tho? was there rpm surge on yours? when that happened? I didn't notice any change in rpm behavior.

nlpamg

I had an rpm surge/vibration.

check if the TB is vibrating.

FrankW

did a visual check while not having the airboxes on. the TB seems fine. no rpm surges either.

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.

Glyn M Ruck

Frank - It could be many things - If it's the main CAT on one side it should throw a code & would not cause the exhaust to pulse - could make a noise though - I'm sure you heard PAPete's Cat. You must do a compression or leak down test to check for valves/rings. Even if it's only to eliminate the possibility. If the exhaust is pulsing it's either no spark, no fuel, burnt valve or broken valve spring. (Worse case scenario is broken ring but it would smoke & tick loudly - I doubt a ring)

Good luck

FrankW

broken valve spring sounds like a major possibility right now.

FrankW

well, went to a local MB specialist that I always do my oil changes with. he doesn't think it's the valves causing the rough idle/misfire. He thinks the wires might be cooked since other than the misfire code for #4 there was also a pending code on #6 which means it's misfiring, but not yet triggering the CEL.

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

Glyn M Ruck

Frank - If there is any suspicion of wires - toss the lot first - cheapest option. Just be careful & get wires that are known to behave on the Benz - Some aftermarket wires cause misfires. I thought your sisters wires/coils were known good. You might be heading for coils as well.

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.

FrankW

the misfire code on #4 went away after clearing the code couple time, so I think the new plugs did "that" trick, but the other wires might still be bad.

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.

Glyn M Ruck

Good - sounds like you have a good experienced guy on the spot. I don't know Magnecor wires but if you C32 guys have good experience with them - Great! It's hard to diagnose at a distance & one can only really stick to basics without being able to drive & listen. I agree with your guy - the engines are tough. Let us know how it goes. I must go to bed. Assen MotoGP in a few hours time.

splinter

Dang, Frank.

Sincerely hope those new wires solve it for you. *fingers crossed*