High CO but normal HC on E200 Kompressor w211

[Peter Calin]

Hi all . I'm only new to the forum so please bear with me.
I have a 2006 E200 Kompressor w211 and I love the car but over the last few months it's been a nightmare for me.
Long story short : I failed the NCT ( I'm in Ireland) due to bad emissions AS it follows:
CO (low idle) : 1.45 ( limit is 0.3)
CO (high revs) : 1.53 ( limit is 0.2)
HC : 73 ( limit is 200)
I have done a lot of work on the car since the first test but it still fails the emission test.
The work done is :
Air filter, spark plugs, MAF, timing kit, catalytic converters, "oil leak stopers" for the camshaft sensor cables, wiring conectors ( at ECU) cleaned of oil contamination, vacuum breather hoses and valve , ECU reflash/remap, self adaptation reset, lambda sensor (pre cat/bank 1).
After all the work the emissions results did change but by only say from CO 1.60 to 1.45. My mechanic told me this is more due to the different values ( revs/ temperature) during the test.
I don't know what to do anymore.
Please , if anyone has any ideas or maybe I am lucky and someone did fix this problem , let me know .
Thanks in advance.

 

[Peter Calin]

I forgot to mention that there is no fault codes coming up.

 

[Oldspanners]

S

Hi all . I'm only new to the forum so please bear with me.
I have a 2006 E200 Kompressor w211 and I love the car but over the last few months it's been a nightmare for me.
Long story short : I failed the NCT ( I'm in Ireland) due to bad emissions AS it follows:
CO (low idle) : 1.45 ( limit is 0.3)
CO (high revs) : 1.53 ( limit is 0.2)
HC : 73 ( limit is 200)
I have done a lot of work on the car since the first test but it still fails the emission test.
The work done is :
Air filter, spark plugs, MAF, timing kit, catalytic converters, "oil leak stopers" for the camshaft sensor cables, wiring conectors ( at ECU) cleaned of oil contamination, vacuum breather hoses and valve , ECU reflash/remap, self adaptation reset, lambda sensor (pre cat/bank 1).
After all the work the emissions results did change but by only say from CO 1.60 to 1.45. My mechanic told me this is more due to the different values ( revs/ temperature) during the test.
I don't know what to do anymore.
Please , if anyone has any ideas or maybe I am lucky and someone did fix this problem , let me know .
Thanks in advance.

The only thing I can see is that you changed the pre-cat sensor, usually with oil in the wiring harness the oil collects in the connector for the post-cat sensor and can contaminate it but you usually get some fault codes.
Have you had it on Star?

 

[Peter Calin]

S

The only thing I can see is that you changed the pre-cat sensor, usually with oil in the wiring harness the oil collects in the connector for the post-cat sensor and can contaminate it but you usually get some fault codes.
Have you had it on Star?

Hi and thanks for reply.
Yes I did have it on star and no fault codes , that is why I never changed/ touched the post cat sensor. I did get a couple of times an error (can' remember the number) that was about self adaptation. But now after all the work and there is no errors for the last month or so. I will check the post cat sensor and maybe that will be the issue.

 

[Oldspanners]

Hi and thanks for reply.
Yes I did have it on star and no fault codes , that is why I never changed/ touched the post cat sensor. I did get a couple of times an error (can' remember the number) that was about self adaptation. But now after all the work and there is no errors for the last month or so. I will check the post cat sensor and maybe that will be the issue.

The only other thing that comes to mind is that if the oil contamination was extreme it could have filled up the ECU but again that usually throws up some codes. Other than that after all the work that you had done is to check all the connectors for any corrosion and correct insertion.

 

[LostKiwi]

What Lambda values are you seeing?

 

[Peter Calin]

The only other thing that comes to mind is that if the oil contamination was extreme it could have filled up the ECU but again that usually throws up some codes. Other than that after all the work that you had done is to check all the connectors for any corrosion and correct insertion.

This is exactly where my big problems start : having no fault codes , the car having no symptoms but still emissions through the roof. I had the car hooked up to the star while driving (I know i shouldn't for safety reasons) so we checked the real values while the car is not just running but is actually driving and the values are all well between the mercedes recommnded values.

 

[Peter Calin]

What Lambda values are you seeing?

Hi
Lambda values were originally 0.93-0.94
Now at the last test 0.97 but the engineer said it keeps dropping to 0.95-0.96. The limit is 0.97 to 1.3.
The engineer said that what looks weird to him is that the CO level should actually oscillae slightly but on my car it just goes up and stays there like it's "stuck".

 

[Oldspanners]

Hi and thanks for reply.
Yes I did have it on star and no fault codes , that is why I never changed/ touched the post cat sensor. I did get a couple of times an error (can' remember the number) that was about self adaptation. But now after all the work and there is no errors for the last month or so. I will check the post cat sensor and maybe that will be the issue.

Just had a look through my cars MOT history and it shows this as a failure;

Exhaust emissions carbon monoxide content at idle excessive (7.3.D.4)
Exhaust emissions carbon monoxide content after 2nd fast idle excessive (7.3.D.3)
Exhaust emissions Lambda reading after 2nd fast idle outside specified limits (7.3..D.3)

according to the garage I bought it from this was cured by changing the after cat sensor which subsequently caused faults when the heater circuit went open circuit due to oil contamination.
I don't know how this corresponds to the test in Ireland.

• 
  
  

 

[Peter Calin]

The only time I got an error after some work was done was P201C mixture format selfadaptation ( FUEL trim). This was not on a STAR , it was right after I changed the cat converter. The guy cleared the code and it never came back.

 

[Peter Calin]

Just had a look through my cars MOT history and it shows this as a failure;

Exhaust emissions carbon monoxide content at idle excessive (7.3.D.4)
Exhaust emissions carbon monoxide content after 2nd fast idle excessive (7.3.D.3)
Exhaust emissions Lambda reading after 2nd fast idle outside specified limits (7.3..D.3)

according to the garage I bought it from this was cured by changing the after cat sensor which subsequently caused faults when the heater circuit went open circuit due to oil contamination.
I don't know how this corresponds to the test in Ireland.

• 
  

I will change the post cat sensor and I'll post the results here. Thanks a lot.

 

[Oldspanners]

Have a look on ebay I got a Bosch for £40 and seem to remember a company in Cork having them for less but the postage to France was too expensive.

 

[LostKiwi]

Also try resetting the adaptations. You'll need a decent diagnostic scanner for this (STAR preferably).

 

[Peter Calin]

Also try resetting the adaptations. You'll need a decent diagnostic scanner for this (STAR preferably).

I will change the post cat sensor and do the self adaptation reset after that . Hopefully it will help.

 

[star]

Engine ecu software update.

 

[Peter Calin]

Engine ecu software update.

Can that only be done in a Mercedes garage ? Or just need the STAR for it ?

 

[star]

You need a genuine star that's connected to MB. A good indie should have (we have ) or stealers.

 

[Peter Calin]

You need a genuine star that's connected to MB. A good indie should have (we have ) or stealers.

I suppose "indie" is an alternative for the STAR ? I am in Ireland so if there is any place you could recommend I would highly appreciate it. Going to the dealer is something I don't really want to do as I had some really bad experience with them.

 

[star]

England? Just kidding.

 

[Peter Calin]

England? Just kidding.