C220 help

[arlolynx]

I have a C220 CDI and it has a rough idle and an indescribable clanking noise from the engine bay. The car drives perfect and is not down on power. I have been to several mechanics and got no straight answer. I tested the injectors using a scan tool and got a correction value of 65 on cylinder 1. Can someone please help because seemingly nobody can figure out the problem

 

[mersum1es]

sounds injector problem. I can't remember exact limits of OM651 correction values plus some scan tools can give value at different units... Clanking noise can be result of more drastic problem than simple small incorrect amount of injection; injector can be left slightly open all the time, and that will destroy your piston for sure.

 

[markjay]

Welcome.

Ideally you'll take the car to an MB specialist who has the MB STAR diagnostic computer, it will give a more accurate and detailed reading of the fault codes, and offer further testing or remedial steps.

If suspecting an issue with one of the injectors, you could try using some diesel fuel additive such as Redex or Forte etc, though to be honest if the car runs fine at higher engine revs then the issue isn't likely to be resolved by a fuel system cleaner (because obstructions tend to manifest themselves at full flow), but for the price of a bottle of additive it's worth trying (and will be good for the engine anyway).