W210 2002 E220CDI Lumpy Tickover

[Pauljames]

I have a 2002 E220 CDI that's done 47,000 miles, tickover was lumpy and the automatic kickdown wasn't working - I've changed the oil and replaced the MAF which has sorted the kickdown, but tickover still lumpy.

On cold startup the car revs at about 900 rpm fine as it warms up and the tickover revs fall the tickover goes lumpy. When the engine is up to normal temparature of 75 tickover is fine.

When on the move driving either warm or cold car is fine.

Have read other threads and suspect it might be worth cleaning the EGR valve ...if so can anyone tell me where it is........ But any other ideas on how to solve the problem would be most helpful...

 

[Naraic]

Normal temp is 88...you need a new stat.

 

[Pauljames]

Will leave it running to get a more accurace reading - is a faulty thermostat likely to cause the lumpy tickover?

 

[WG M-B]

Not really no it wont. If the egr is not seating correctly you will get black smoke on open throttle. How lumpy is the idle? It could be a shot engine mounting. If its lumpy to the point you have a misfire on idle then suspect a faulty injector spray pattern

 

[Pauljames]

Thanks for the response, when its idling the revs regularly drop perhaps to 400 then picks up again to normal then drops again to 400 then picks up again. It seems to be almost a regular cycle every 3 or 4 seconds the revs drop then picks up.

The car doesn't seem to be smoking at all....

Thanks

 

[WG M-B]

Its best if you get the car on a star machine to check it over. Where are you located?

 

[Pauljames]

Up in Bolton, I know a good Indie so will take probably get it booked in.

 

[WG M-B]

Thats good. Your indie should be to the bottom of it in no time!