220 CDI 2003 engine running unevenly on tickover

[kingster]

I wonder if anyone may have experienced the problem I currently have and could offer any suggestions?

I have a 2003 220 CDI Coupe. Whenever the temperture is cold (below 6-7 degrees C) the engine runs very unevenly when on tickover - eg standing in traffic etc. The car shakes slightly, the rev counter moves up and down and the engine feels like it might cut out (although it never does). This last for 15-20 mins and then it clears and is fine for the rest of of the journey. It does not seem to affect performance at all whilst actually moving. It doesnt happen at all on milder days.

I have taken it to a Mercedes specialist and also a MD - the injectors have been cleaned out and the computer test indicated a faulty Air Mass SEnsor which has been replaced but made no difference to the problem.

I am anxious to avoid repeated trips to the MD whilst various other things are tested/changed and just wondered if anyone might have experience the same problem and might know what it is?

Many thanks

 

[television]

Welcome to the forum

Is your car getting up to the full running temp

 

[BlackC55]

Is the belt tensioner flapping about?

 

[television]

Is the belt tensioner flapping about?

Good point Ollie,,I am

 

[kingster]

Thanks for your interest.

The running temperature is 70-75 degrees C and it takes approx 10-15 mins to reach this.

I'm sorry but I don't know how to locate the belt tensioner! However, having checked under the bonnet as carefully as I can I cannot see anything which appears to be flapping around.

Thanks again, please let me know if you have any ideas as to what the problem is,

Cheers

 

[television]

On the front of the engine you have the serpentine belt that drives the alternator and fan, look at the pulleys where the belt passes over to see if they are moving around much, it will be the center one of the 2 on the right

http://www.detali.ru/cat/oem_mb2.as...647716.651&CT=F&cat=69J&SID=21&SGR=050&SGN=01

 

[kingster]

Thanks Television. Will have a look over the weekend and report back.

 

[Janice321]

Dont know if this will help (W203. 2002. 95K) the Temp was only going to 70/75 C and ran a little uneven. Had the thermostat replaced. Stat cost £30 + vat. also ran a bottle of injector cleaner thro . Temperature now goes to 80/85 even on short runs and the tick over is also better.

 

[Chopper]

I had exact same problem ,"injectors" I think is your problem .What year is the car and how many miles ?

 

[w mckeown]

i have the same problem with my 2003 220cdi as well but my erratic tick over is all the time, this only started after i had a new fuel pump fitted and other diesel leaks fixed. a merc specialist has tested and no faults diagnosed, they also said that this erractic tick over was not that bad so i guess i will have to live with it for now. i have done the injector cleaner stuff but still no change.

 

[Chopper]

injector cleaner is a waste of time and money ,you need injectors pressure tested and replaced if needed

 

[kingster]

Thanks for all of your comments.

The car is a C Class Coupe 220 CDI with 57K mileage - I did have the injectors cleaned at the Merc Dealers but this didnt help at all.

I did check the belt as Television and BlackC55 suggested - the small centre wheel of the three on the right does move around alot when the tickover is uneven and doesnt do this when its running OK. I wonder if this could be the problem? Or could this just be caused by the uneven running? If this is the problem I wonder why it only happens in cold weather and for the first 10-15 minutes?

Thanks again