M113 shaking at idle
 

Hello everyone,

I am having some problem with my CLK 500 MY 2005 with 7G. When idle, I can feel some vibrations inside the car. I can feel them through the car body and not through the steering wheel. No codes on SD, I have replaced all sparks and ignition coils, cleaned MAF and nothing has changed. Mechanic has checked the engine and transmission mounts (they are ok), checked the engine compression (its ok). The car has no oil leaks exept one small on oil filter. I am using Motul 5w40, I change it every year (every 5k). I tried engine flush from liquy and molly but it didnt work.

I also can hear some knocking sound in the engine on Passenger side, but I have read many threads about it.

It seems like a missfire every 2sec, but the ignition system is ok and there are no codes. Any ideas? EGR Valve? I can post a video of engine running.

Greetings

My guess will be misfires caused by ignition or fuel injection. I have never seen it written anywhere, but from my reverse engineering of Mercedes it's obvious that they use leaky bucket algorithm to trigger check engine light and throw the codes. In other words you can be misfiring at certain frequency which will not show any errors. I've also found a simple way to troubleshoot it - you need the Star system or someone who has one. Go to the Fault Counter for Engine Control Unit. Display in real time "Specified value" and "Actual Value" for all of the cylinders. If the actual values are not 0 but get set and cleared in a few seconds (never accumulate enough to trigger errors), you have a misfire the computers don't notify you about. Good luck and let us know what you find out.

And just because you replaced something, it does not mean that the replacement is good. The worst troubleshooting I ever had was when the replacement ignition part was faulty and I never gave it a second look until I checked everything else. Check to make sure that all the connections are good as well

I have this problem on my C55 as well. Exact same issue, no codes, but something is definitely off about idle. Next thing I'm going to replace is the CPS (crankshaft position sensor) as they are known to be problematic. If you do this, make sure you get OEM Bosch, I've read that other ones from local parts stores don't work correctly. I'll follow this thread closely

For me CPS was usually accompanied by hard starting as well, but keep us posted what you discover

Would changing the camshaft cam adjuster magnets and/or camshaft position sensors make any difference for this issue?

Not unless you are getting codes indicating they are bad.

Unfortunately I havent found the solution yet. The car has also less power (around 2 sec slower between 100 and 200 km/h). I changed MAF ( no code, but I was told that the voltage was high in the old one), changed all breather hoses, checked all vacuum hoses (they are ok). I also sprayed deodorant around the running engine to check if there is any leak in intake manifold, but I found nothing. Any ideas?

You all should have your motor mounts checked... :) Ask me how I know.

I did. Motor mounts are 100% ok. I know the feeling of bad mounts and its different.

Now, you don't state the milege on the car, but being a 2005, you probably have done 120K miles.

From the above description, I would say, that you have a problem in the fuel system, probably injectors. You can try injector cleaner, in the petrol. If that don't help, have the fuel pressure checked, and if that is okay, have the injectors tested, cleaned and calibrated if necessary, or replaced.

When did you last have the fuel filter changed ?

I dont event remember. Ok, good advice, I will replace fuel filter and check fuel pressure. I added something MB approved to my fuel to clean injectors, but nothing has changed.

I can hear that all fuel injectors are working. I do not have any problems with starting the engine, so I dont think its the fuel pressure. Any other ideas? I can also hear knocking noise (lifter probaly) but I don't think it could cause this problem.

I guess I have something same or similar. M113 with 7-speed. I can feel the vibration on the whole vehicle especially when I put the car in D. Even mirrors are shaking or some plastic components coming into the resonance.
I checked the for vacuum leaks with a smoke machine, didn’t find anything. I was disconnecting the coils one by one to find it actually swas starting to misfire when disconnected.
Also no codes, no CEL.
At first I was suspecting engine mounts, but changing the gears is smooth.
Want to check if disconnecting the MAF and putting the engine into the LIMP mode will change anything.

Motor mounts, motor mounts, motor mounts.
Can't repeat it enough. They fool even experienced professional eyes during inspection.

I've replaced mine along with several others for relatives and friends. Cars had mileage between 98k to 130k. Vibrations were 100% gone after all mounts were done. The difference was like night and day. No excessive engine movement or leaks on any of them prior to replacement. The only thing I noticed was a bit of a height difference compared to new ones. Pretty difficult to see that while it's in the car.

I changed mine only after finally a friend got in the car and asked why everything was vibrating. I got used to it over time.

All of the above is assuming everything else mentioned in this thread has been checked. I would also add a bad crankshaft pulley to the list of items that can cause vibrations on M113.

Most people are running on bad motor mounts and don't even realize it!

Ordered a set of motor and transmission mounts today :)

while the new engine mounts are still in the trunk I guess I probably found a cause of the vibration:
https://cimg6.ibsrv.net/gimg/www.mbw...2636be071.jpeg

Excuse my ignorance, but what exactly is the problem depicted? Is there degraded rubber in the pulley?

The picture show the Harmonic Damper, fitted to the crankshaft. Besides pulling the belt, it has the function of dampening the torsional harmonics from the crankshaft, preventing fatigue failure of the crank.
The vibrations you are experiencing could very well come from the faulty damper, since the missing rubber has changed the tune of the damper, that it is now out of tune with the harmonics it's supposed to dampen.
Normally, in such a case, you would expect to see the rubber torn apart, instead of the bond between rubber and steel failing. This indicated a manufacturing error.
The rust in the grove indicates that it has been going on over some time, and the alignment of the inner and outher part is still in order, so the damper has not failed yet.
I suggest you exchange it with a new MB original, not a used one from the scrap yard.
These vibrations you feel, if they come from the crankshaft, they are very harmful, increasing fatigue load and premature crankshaft failure.

I placed an order for the new pulley, bolt, belt few moments ago :) Decided to roll the dice and purchased Corteco pulley, since original cost 25% of what I paid for the whole vehicle :) If the Corteco HB gonna fail - it's covered with FCP euro warranty :)
Found it accidentally - was rinsing the cooling system and noticed something was wobbling while engine was on. Took a better look and saw this guy with a half of rubber missing.

It's a good thing to change the seal as well, to avoid an potential oil leakage after fitting the new damper.
The Tune of the new damper is critical, so you will instant feel if it's right, after you fitted it.
Some of those aftermarket parts are only close by, not exactly tuned.

Correct, front seal is on the order too. We'll figure it out shortly - how good or bad the new pulley is balanced! Thanks for the advises!

Chaned the harmonic balancer using this new official holding tool. But after replacement the vibration is still there (may be a bit less).. When I took a pic onto the engine while I was shifting between the PRND - it’s standing still- doesn’t shake a tiny bit. I’m not sure if it is a sign of a good or bad motor mounts. It looked like the motor was solid to the chassis. I thought it should move a tiny bit when switching the gears.

https://cimg7.ibsrv.net/gimg/www.mbw...687c29ca3.jpeg
https://cimg8.ibsrv.net/gimg/www.mbw...698767314.jpeg

Bugger, would have been nice if it had been the damper.

To check the motor mounts, open the hood, get in the car, turn on the engine, press the brake pedal firm, and engage transmission in D
Press the throttle a bit, and you can observe the engine movement from inside the car.
The engine should not lift more than half an inch in the left side, then the this side is okay.
Now engage transmission in R and repeat. The right side should not lift more than half an inch as well.
Worn out engine mounts can let the engine lift up to 2 inch, in either side, usually the left, since it is under lift load when driving in P