C200 Kompressor shuddering when idle

[zmz]

Hi if anyone's got any info. If i've been driving for a while then come to a stop my car starts shuddering and the fuel injection light comes on and it's hard to accelerate, so i have to turn off engine and restart then its ok. been quoted £3500 to investigate prob and possibly replace a cylinder on a car thats now 3 years old. by the way prob started as warranty finished!!!

 

[BlackC55]

Have you had the car looked at already?

If it has a missfire (i suspect you have) this missfire needs to be highlighted and diagnosed properly.

Take it to a good independent specialist near where you live.

You can't replace a "cylinder" as you have said. Do you mean cylinder head?

 

[zmz]

Thanks for the advice. It has already been looked at but all they do is run a computer diagnostic and reset the amber fuel injection light. They MB have told me they need to do further investigations by taking it apart. Also this problem seems to happen when i've been on the motorway and then come to a halt......Will take it to an independent.
thanks

 

[jberks]

Highly unlikely to be anything serious.
The £3500 was a bad taste joke I suspect. The light, judder and poor acceleration are a manifestation of "safe mode". This is where the computer has a problem and gives up, and instead of running the engine itself, drops to default settings. Switching off and on again resets it (like on your PC) - hence the problem appears to go away..
This indicates that whatever the problem is, is minor and so has gone away. A major expensive mechanical problem won't do this. A dodgy sensor will.

Pound to a penny, it will be the MAS sensor which is around £200-£250 from the dealer, an easy 10 min DIY job to fit. Many can also be bought for considerably less too. Post back if you want more details.

As I suspect you're not too mechanically minded, the above advice is good. Find an indie and I suspect you'll be on your way for around £300.

 

[zmz]

Thanks for the advice have it booked in next week at an indi who will run yet another diagnostic will keep you guys informed of outcome. official dealer really did quote me somewhere in the region of between 3-4K and said it was prob cylinder head but not sure. does a diagnostic give you an accurate reading of what is going on with the car?:-?

 

[BlackC55]

If the dealer recomends a cylinder head replacement is suspect it has low compression on one cylinder. It was a common problem when the 271 engine came out. The valves do not seat properly in the head allowing poor compression and therefore a warning light illuminates.

You need a compression test as well as a interrogation of the stored fault code. A simple diag test shows briefly what the problem might be; its just a guide for the technician. It is very unlikely to be an air mass problem as the 271 engine tend not to suffer the same as the others.

I take it you have the 271 engine???

 

[television]

If the dealer recomends a cylinder head replacement is suspect it has low compression on one cylinder. It was a common problem when the 271 engine came out. The valves do not seat properly in the head allowing poor compression and therefore a warning light illuminates.

You need a compression test as well as a interrogation of the stored fault code. A simple diag test shows briefly what the problem might be; its just a guide for the technician. It is very unlikely to be an air mass problem as the 271 engine tend not to suffer the same as the others.

I take it you have the 271 engine???

Was not this the one where the valve seat cracked ?

 

[BlackC55]

They didnt crack. It was just a very poor seal between the seat and valve. I have replaced 3 and repaired one; all with the same problem.

 

[jberks]

If it is the old valve seal issue, then the next port of call should be MB. After all, this was a serious manufacturing defect that MB are fully aware of and should be paying for. I don't see the warrany expiry as being relevant (or I wouldn't if it were mine). The car is a shade over 3 years old and a major engine component has failed from a known manfacturing/ design fault. I would demand that MB fix it FOC. You may not get 100% but you should get a substantial chunk.
I'm just surprised that this manifests itself in this way. I'd have expected it to be present all the time.