Mission impossible - C180 Kompressor Poor performance and bad idle rpm
I have a 2005 Mercedes C180 Kompressor. Actually it has 90K kilometers and I'm having some weird problems. When the car reaches temperature above 85 degrees Celsius when driving on traffic in around 1000-1500 rpm it will drop engine rpm to 450-500 which is not normal as the engine has to maintain 650 rpm with gear engaged (video link in the attached text file). Also the other problem is when driving on high way with same operation temperature, the car won't have enough power to accelerate, it feels like driving a 1200CC petrol engine and not 1800CC with supercharger!
On my way to troubleshoot this issue I've done the following operations:
1. Vacuum system checked, resealed / resolved any vacuum leak.
2. Engine oil changed
3. Torque converter replaced (suspected this was causing the issue)
4. Tested with another MAF (same exact PN)
5. Tested with another throttle body
6. Tested with another set of cam sensors
7. Transmission recalibration
8. Learn throttle body rpm with gear engaged.
9. Fixed air intake duct to the air filter.
10. Replaced vacuum pipe under the air box filter which is usually was defective.
11. Replaced engine mountings (due to strong vibration on rpm drop)
12. Replaced ignition sparks
After all the above interventions including firmware updates with DAS Xentry etc... nothing seemed to be fixed! Also around two weeks ago I drove my car on a mountain road where the climbing was considerable and during this trip the performance was very disappointing.
I'm thinking to replace all four Ignition Coils right now as the fourth one when testing the engine on full load (5000+ rpm) went off (P0304) - and it was misfiring. Maybe the coils are sensitive to the temperature of the engine and that's why engine performance degrades when hot.
In addition scanning my car with generic OBDII scanner I got the following codes P201A, P203A.
Car information:
Engine : M271.946
Transmission: 722.695
Odometer: 93000 km
Engine Oil change: 90000 (last oil change)
Please advise any possible solution to this issue, all left to try after ignition coils replacement is another engine.
Thank you in advance!
Best regards
Last edited by lsdlsd; Aug 11, 2014 at 05:50 AM.


