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Mercedes S Class 2005: Problems with black smoke development, engine performance and idling function

Hello everyone, I have a strange problem with my Mercedes S Class, model year 2005, gasoline engine. When I accelerate, black smoke comes out of the exhaust, the engine light comes on, the engine shuts down and loses power. Also, the engine runs rough, the car jerks when accelerating, starts poorly, stalls while idling and shudders when idling. I'm not sure, but could a fault in the idle control be the cause? Has anyone had similar experiences and can give me some troubleshooting tips? How was the problem fixed at the garage? Thanks in advance for your experience reports and advice!

(Translated from German)

4 comment(s)

Hi there, I had a fairly similar situation with my 2003 Mercedes E Class. I'm not a master mechanic, but I do have a bit of experience with cars. I took the car to my regular garage, they always know what to do. They then discovered that the cable/plug on the idle control valve was defective. That cost me 155 euros. One request: Can you please tell me how many kilometers your car has run? That could help me to tell you more precisely which parts are probably affected. Hope that helps!

(Translated from German)

Moin Moin, thanks for the info. My car now has 134061 km on the clock, the last service was a good 50 km ago. Is it possible that the cable/connector on the idle control valve is broken so early? Thanks for the tip anyway! Best regards!

(Translated from German)

Well, well, damage to the cable/connector of the idle control valve could theoretically occur at any time, depending on many factors such as material fatigue or mechanical stress. In my E-Class, this was the case at around 1450 km. However, your problem is more in line with a damage symptom, which indicates that the mass air flow sensor or the exhaust valve could be defective. An engine control unit (ECU) malfunction could also be possible. As the Check Engine Light is active, a scanner could be connected to read the fault codes - this can provide really helpful info! Whatever it is, I recommend you get it checked as soon as possible as it's likely to put a lot of strain on your engine system and could also cause other faults. Have a good trip and cheer up, you'll be fine!

(Translated from German)

Hello, thank you very much for your detailed advice and help. I will take your advice to heart and take my car to the garage as soon as possible. An ECU error and possibly defective parts such as the mass air flow sensor sound pretty serious. This also explains the rough idling and the strange behavior when accelerating. It's a bit reassuring to know that I can at least narrow down some possible causes now. I'll keep you posted as soon as I know more. Thanks again and all the best!

(Translated from German)

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