engine idle problem - Benzworld.org - Mercedes-Benz Discussion Forum

auras1 · 09-22-2009, 04:25 AM

Hi,
I am owner a B200 Turbo (second hand) with CVT of 2 months and I am following problem:
Engine idle is not constant ( up and down between ~ 750 RPM and ~800 RPM).
I went to Mercedes dealer and they rewrote the parameters of computer, but without effect.
I read on a german forum that is normal to do so because of the automatic transmission.
It is possible?
Any suggestion is welcome!
Thank you!

kdbcom · 09-22-2009, 02:34 PM

Hi auras1 & welcome to the forum, I think this has been posted before on this forum possibly a couple of years ago & also possibly within the past 6 months. You will probably need to trawl through the posts to get an answer unless one of the members that had the problem notices your new thread.

Where are you located by the way ?

jeffplastow · 09-22-2009, 06:47 PM

Do you think the idle is fluctuating a lot, or do you just think it's rough?

Even for a 4 cylinder, the B200 Turbo is not a smooth engine at idle - pretty decent when cruising and overtaking (in my opinion).

My idle has been "rough" since new and 33,000 km later is no better or worse. I've decided to find it a charming quirk of the car.

Jeff

auras1 · 09-23-2009, 05:31 AM

Hi Kdbcom,
I am from Romania.

Hi Jeff,
You described very well my observation relating my idle. Yes, it is "rough".
This happens because is a turbo engine?
The same engine but without the turbo ( only B200 model) not has this "rough" idle?

Thank very much!
Auras

B200Turbo · 09-23-2009, 11:55 AM

Is your A/C compressor running?
Try it without it.
And yes CVT can give the engine fluctuation you describe but it should
not be rough idle.

vanctour · 09-23-2009, 01:35 PM

I have a 2006 B Turbo and it idles a little rough. Not as refined as the larger Benz's. It's quiet and drives smooth, but when it sits there, regardless of gear selection, you can just visibly see the steering wheel tremble and feel it in the car. It's not that bad, but I think it is more than a Benz should have. My 2 cents.

Derek Lecours · 09-23-2009, 01:47 PM

My B200 holds steady.

kdbcom · 09-23-2009, 02:12 PM

Possibly just a problem with the turbo cars then ?

Members have complained of vibration through the pedals of the diesel cars but I think this is a different issue.

vanctour · 09-23-2009, 02:26 PM

My old Ford shook like an earthquake hit! Put it in neutral, and it was like the engine was off. With my B, the shakes are like a new top loading washing machine, regardless of Neutral gear or Drive gear. Nothing to run back to MB about, but I would have thought that MB's would be next to flawless in this department.

jeffplastow · 09-23-2009, 06:02 PM

Quote:

Originally Posted by vanctour

I have a 2006 B Turbo and it idles a little rough. Not as refined as the larger Benz's. It's quiet and drives smooth, but when it sits there, regardless of gear selection, you can just visibly see the steering wheel tremble and feel it in the car. It's not that bad, but I think it is more than a Benz should have. My 2 cents.

That is a exactly like my car. The RPM can fluctuate a bit at idle, but overall it is fairly steady. It's the vibrations through the steering wheel I find slightly annoying. I'm assuming it has something to do with stiff engine mounts and it's location.

I have a feeling the turbos are affected more. I've driven a number of non-turbo loaners and they do seem smoother.