99clk320

Hi All. I have a violent shaking problem with my 05 E500 4matic, and its been approx 2 weeks now. Took it to an indy, no codes and nothing wrong with the sparkplugs, the cats, no leaking valves, the motor mounts, etc.

The car only shakes when idle, regardless if I'm in Park, Drive, or Neutral. Once i'm on the highway and the rpm is >1,000, not problems whatsoever.

I just tried following Pancho's excellent write-up on cleaning the MAF with the CRC MAF cleaner but to no avail. Short of springing for a new MAF, does anyone see a problem with swapping out the part that houses the MAF wire element (not the entire outer tube) from my 05 E500 4matic with an old one that I had replaced prematurely on my 99 clk 320? (I saw that they both had PBT-GF30 stamped on it but it turns out, that just means its made of the same material http://www.air-mass-meter.com/2009/g...airflow-meter/.) I already assembled everything back together so can't compare part numbers at the moment, but they seem to be exactly the same size and dimension.

Even though its an older part, its definitely in better shape... Any issues?

Benz-O-Rama

Shaking at low RPMs is a common problem on the W211s. Many times it ends up being the fluid filled engine mounts have failed.

99clk320

Thanks Benz-O-Rama, the mounts don't look collapsed via visual inspection, and there's definitely a problem as you can hear the car chugging from the exhaust, instead of flowing smoothly. The indy shop checked the emissions and they looked fine though. There's also sometimes (not often, sometimes) an egg smell which has me thinking its some kind of fuel/air mixture related problem.

Problem is that its not thrown up a CEL or any codes so I'm confused as heck. What's all this coil pack and wire stuff that I've read about. Would any of those cause the shaking and that smell?

I've got 78k miles on the odometer so I've gotta figure out fast if this is a catalytic converter issue since that's covered under warranty only until 80k miles I think. I put on 3k miles a month so only have two weeks before i'm out of luck...

Thanks!
(btw, for your comedic enjoyment, my extended warranty just ended last month. Prior to that, I had no issues. It's always funny how well this stuff is timed.)

Benz-O-Rama

Hmmmmm, egg smell.....

First thought is Cats. Doubtful that it's spark related, as the car smooths out above idle. Any black smoke out of the tails? If it was MAF, it could be running a bit rich, which could cause rough idle, but usually is accompanied by a bit of black smoke. Also check your rear bumper, near the exhaust tips for black film/soot.

99clk320

Hmmm, just checked again and not really. There's a tiny bit of soot there, but not much. Prob just enough to represent 5 years of driving.

I do appreciate the feedback about the sparks, as that will save me quite a few troubleshooting steps. I understand now that because it's smoothing out above idle, that means I can skip new spark plugs, new coil packs, and new wires.

Any sense on whether a cracked hose or vacuum leak or bad engine mount symptoms would also disappear after picking up the revs?

ohlord

insert is not going to be scaled to the outputs for the 500.
You could have a partially blocked cat causing the issues
Why not get it into the dealer and have them get it on the sds and a scope and do a cat eff test. If they are bad they gladly replace no sweat off their backs they charge it back to Benz. Either way it seems like it is beyond your indies ability esp if they don't have an SDS. If it is not a cat issue at least you find out what it is before it becomes a cat issue which it will shorty if not taken care of.

99clk320

Thanks for that @ohlord. Guess I have no choice so will head there first thing in the morning. Should I just ask for the "Cat Eff Test" by name in addition to the Star Diags? Not sure if they "charge by the test".

One more bit of data to throw in the mix,... when I was cleaning the MAF earlier, I had accidentally started the car up without reconnecting it to drive down my driveway. The car was still sputtering so I suppose the MAF was definitely never the issue.

Will post my SDS results tomorrow. Thanks!

99clk320

OK, mb just called and said that the problem is with the eGR valve, $721 for parts and labor. Is this is a DIY item or is that a fair price from the dealer (considering that its inclusive of the $210 diagnostics charge, so its really like $500 more).

Benz-O-Rama

If you're in NYC, call Bruce at TT Motorsports and see what he can do for you.

Check parts.com or autohausaz.com for the part.