Rough running - lacking supercharger boost

[darrenb1707]

I recently created a thread entitled 'Coil packs???' relating to problems I have been having with my CLK 230 Kompressor. Not so sure it is the coil packs but I'm still having issues and I'm hoping someone can offer some advice. Here's a brief outline of what's been happening:

Initialy the car was running fine. I stopped, parked up and when I restarted noticed the idle was very lumpy - revs were fluctuating from between normal and maybe 100rpm more than normal. The engine was also juddering when stationary. When I drove the car it felt like it had no supercharger at all. Very flat performance and throttle response. I didn't use the car for another couple of days and when I started it next time it ran as completely normal.

I did about another 100 mile journey with no performance problems. Later that day when in city traffic the car started juddering again when idling at junctions but still had normal performance. I was just about to join a dual carriageway (intending to give it some stick to see if it would clear the fault). I pulled out to accelerate and I got the initial throttle reponse of the supercharger then it was like the boost just disappeared and it was running with no supercharger at all. Have since used it the next day and it is still 'flat' with no apparent supercharger working and lumpy idling.

I have previously gone through the whole 'blocked nozzles fix' detailed elsewhere on the forum to fix MAF oil contamination problems. I have also recently fitted a new geniune Siemens MAF (the later CLKs use Siemens rather than Bosch). I gave it a clean with IPA anyway but it has not resolved the problem.

So I'm not sure where to check next. Potential suspects maybe:
1) Coil packs - can these work sometimes and not others?
2) Lambda/O2 sensors?

Any help and advice would be appreciated. I'm not sure what to do next

Thanks

 

[bigasotonuk]

Hi,
Please bear in mind that this something I have read, can,t even remember where possibly on here but I believe that there is a electrically operated flap somewhere within the intake system that directs the air from the supercharger.
Also worth checking the intake pipes as a faulty breathing system can cause oil contamination of the MAF/MAS sensor.
Take a look at is thread re, breathing system, hope this has been of some help.
http://forums.mercedesclub.org.uk/showthread.php?t=34036

 

[darrenb1707]

Hi,
Please bear in mind that this something I have read, can,t even remember where possibly on here but I believe that there is a electrically operated flap somewhere within the intake system that directs the air from the supercharger.
Also worth checking the intake pipes as a faulty breathing system can cause oil contamination of the MAF/MAS sensor.
Take a look at is thread re, breathing system, hope this has been of some help.
http://forums.mercedesclub.org.uk/showthread.php?t=34036

Thanks, I think the flap you mention is the supercharger actuator flap which I did wonder if that might be the problem. Been trying to find where the multiplug is for this.....not sure of the exact location. I wanna check if the wires are maybe chaffed or shorting out intermittently.

MAFs fine...It's just been recently fitted with a genuine Siemens part. There's no codes and I gave it a clean with IPA to be sure.

Frustratingly it's a intermittent problem.....today driving to and from work the car was fine!

 

[star]

check you maf is not contaminated again. oil sits in the inetrcooler for some time. try another maf.