M271 issues

[C200kamh]

Hi guys I have recently baught a c200k
And I've noticed that after 100miles or so the eml light comes on and brings
A code p2058 upstream control fault.

What can cause this issue.

Is it the sensor or a vacuum leak. How would I perform a smoke test to prove its not a leak.

And also when I start the car from cold sometimes it's sound really rough and after 1 min or so runs smooth.

Do they have a cold start valve on these engines.

Thanks

 

[alecmascot]

Have a read :

The Complete M271 Engine thread. ( Revised and Updated ) | Engine

The Complete M271 Engine thread. ( Revised and Updated ) People are forever asking about how to mod their M271 C180 Kompressor so I thought some work was required to help guide us all! Hope this helps someone. The Complete M271 Engine thread. As you know a number of people regularly...

forums.mbclub.co.uk

 

[Stocious]

Sounds like an open loop issue, apart from the stored code

 

[C200kamh]

Hi thanks for the reply.
What is a closed loop and how can I fix it.

Also my mpg is very poor low 20s at best

 

[Stocious]

There’s open and closed loop on modern fuel injected cars, open loop is achieved on cold start , and runs on a set map stored within the ecu, such things as cold start enrichment, closed loop is when the engine relies on inputs, such as oxygen sensor, maf and coolant temp, closed loop is achieved by the oxygen sensor getting to a certain temperature so it can function, then the ecu can fine tune fueling to be at its best, your car is not running right in open loop

 

[C200kamh]

So how do I go about fixing the issue.
What are the causes for this to happen.

Any help would be much appreciated

Thanks

 

[BlackC55]

It sounds like a faulty o2 sensor. Usually they fail on this engine due to oil ingress in the engine wiring loom that comes from a cam magnet. Take the o2 sensor connectors off (there are two of them) and see if there is any oil in there.