Help Idle Not Even
Thread Starter
Newbie
Joined: Jan 2007
Posts: 8
Likes: 0
From: TORQUAY DEVON UK
CL55K AMG
Help Idle Not Even
HELP MY CL55K AMG 2002 HAS A VERY UNEVEN IDLE WHEN IN GEAR OR NOT . WHEN HOT OR COLD SPARK PLUGS AND LEADS CHANGE CRANKS SENSOR NEW AND NO FAULTS FOUND .MERCEDES HAVE HAD CAR FOR ONE WEEK AND HAVE NOT FIXED IT YET CAN ANY ONE HELP ????????
Senior Member
Joined: Nov 2001
Posts: 291
Likes: 0
From: Portland, OR
2001 CLK320
The Benz V-blocks (in the North American versions) have two O2 sensors for each bank for a total of four sensors. There's a pre-catalyst and post cat sensor for each side.
Another item to check out (and is a very common part to fail) is the Mass Airflow Sensor, a.k.a. Air Flow Meter. When these get contaminated it will throw off idle quality and emissions levels (typically get a fuel trim error code). This can also cause drivability symptoms as well.
These sensors have a heated film surface that measures the resistance based on the temperature change due to airflow volume - they're sensitive deivices. Another thing to check out is whether there are any vacuum lines broken or leaking - this will throw off proper operation as well.
I'm not sure how the emissions controls are implemented on UK models, so there may be differances.
In the 'states we have OBD-II systems that have a lot of emissions diagnostic codes and faults (mandated by our EPA) that I'm not certain if your version may have all those features. I know the European market systems are moving closer to our versions, but I don't have first-hand experience to draw upon how your MY02 version may differ from what we have on our cars.
Another item to check out (and is a very common part to fail) is the Mass Airflow Sensor, a.k.a. Air Flow Meter. When these get contaminated it will throw off idle quality and emissions levels (typically get a fuel trim error code). This can also cause drivability symptoms as well.
These sensors have a heated film surface that measures the resistance based on the temperature change due to airflow volume - they're sensitive deivices. Another thing to check out is whether there are any vacuum lines broken or leaking - this will throw off proper operation as well.
I'm not sure how the emissions controls are implemented on UK models, so there may be differances.
In the 'states we have OBD-II systems that have a lot of emissions diagnostic codes and faults (mandated by our EPA) that I'm not certain if your version may have all those features. I know the European market systems are moving closer to our versions, but I don't have first-hand experience to draw upon how your MY02 version may differ from what we have on our cars.
