engine/vibration problems - PeachParts Mercedes-Benz Forum

Hocky · #1 07-25-2003, 07:13 PM

When I cold start, the steering wheel vibrates a bit and the rev counter fluctuates around 900 rpm + / - say 5 or even less, but you can see the movement of the needle . That is very little fluctuation, but the engine sound varies with the peaks. The usual RRrrrr has the ERrrr, ERrr, ERrr whenever the peaks come on every second. Does this sound very familiar to any of you guys out there

Otherwise the car is ok. When it is warm after a good run, this sound and vibration seems to go away or I get used to it or because the doors and windows are closed anyway and I can't hear it.
The only other thing I am still baffled about is the sharp jerk from 1st to 2nd, or is it 2nd to 3rd? Mine starts from 1st with the "S" selected, or 2nd with the "E" selected. I know everyone tells me it was designed to be that way, but it just does not explain why other makers got away without it and why Benz couldn't find the more user friendly way at that time(around the Cat system) instead of this rude jerk which is very annoying and embarassing with friends/passengers more used to other makes without this HICCUP. My car is a 1994 Euro C180 auto.

suginami · #2 07-25-2003, 07:14 PM

Have you inspected your motor mounts?

psfred · #3 07-25-2003, 08:08 PM

Check for a vacuum leak, too -- this will account for the hard shift, and when you fix the vac leak, the tranny will shift smoother.

Peter

#4 07-25-2003, 10:34 PM

My '94 C220 shifts hard too.Also when the car is on drive and my foot is on the brake it vibrates terribly.When you say check for vacuum leak do you mean a general vacuum leak or should I check for a part of the the transmission with a vacuum.I don't know much about transmissions.Thanx.EDE

hocky1 · #5 07-26-2003, 06:37 AM

I still reckon that the famous jerk in the transmission from 2 to 3 or was it 1 to 2 was not a design feature. Maybe the pre-heating of the Cat was what the designers wished for, but I still think that the bad jerk was unexpected and they did not know how to get rid of it. I still think it was a design mistake thats why other car manufacturers didn't produce the same effect although they also had Cats in the cars they made. So why all the bull and crap about it being a design feature? Who in his right mind would create such a hiccup when a normally thinking car designer would create machines which are smooth and have no baffling bugs in it? Luckily they didn't design it to jerk badly all the way from 1 to 4. Obviously it was a mistake(the jerk, not the pre-heating) because they finally got rid of this in later models and realized their mistake. There should be a class action for replacement of the transmission as we have to suffer this for the rest of our days with the car having paid so much for it.

psfred · #6 07-26-2003, 12:21 PM

Any air leaking into the intake manifold that does not go through the mass air flow sensor is a vac leak.

The AC system, the transmission shift harshness control, and engine controls are all vacuum powered, along with the brakes, so a leak in any of them will give you out of control lean mixture at idle (rough running) and low vac in the manifold. This will produce the hard shifts (and remember, MB trannys don't slop form gear to gear like a GM slushpump -- that's why they go 300,000 miles rather than 90,000). The AC vents will close under acceleration if the leak is pretty bad, or the mixture is too lean.

Peter

trueog · #7 02-10-2005, 04:03 PM

I had the same problem with my car, c220. Turned out the engine mounts were the cause. In my case, one was worn and the other had collapsed, which led to unbearable vibration. I think you also need engine mounts.

I'll be honest be prepared to spend lots of money on repairs for your car.
My C220 has taken over $15 000 IN REPAIRS! in the last 5 years, and now i have a tranny malfunction beggining to happen.

My '98 BMW 528i in the mean time, has only needed 500 dollars in repairs, and that repair was a water pump. Rest has been regular maintenance.

This is my second bad experiance with mercedes, I'm starting to wonder how reliable most of there cars still are. Or do is my BMW just lucky....

benzboy87 · #8 02-11-2005, 08:51 AM

That's a shame. I had my C220 for several years and only had to do typical maintenance to it until i totaled it. I had it rebuilt but then the airbag light was on (which was not on until the MB dealer took the bumper covers off to repair them) so I got fed up with the dealer and bought an ML (big mistake). I sold it to a friend that was well aware of the rebuild and he has had no problems since.
Do a search with "tranny piston failure" and you will find several threads with info for you.

benzboy87 · #9 02-11-2005, 08:54 AM

Sorry. Got your thread and another thread mixed up. Maybe the vacuum modulator on the side of the transmission is faulty? This would cause hard shifting but usually through all of the gears. Adjust Bowden cable?

G-Benz · #10 02-11-2005, 10:09 AM

As most folks have already diagnosed, you have two distinct issues. The vacuum leak if causing your idle to surge as you described, and your worn motor mounts are the culprit to your vibration issues.

The vacuum leak is usually traced to one of the myriad of hoses throughout your engine.

After 4 1/2 years of enduring the idle surge, my indie solved the vacuum leak on my W124 and the surging has stopped. Now I have to bring it in for new motor mounts later as the vibration is now prevalent since the engine stopped surging...