W205 OM626 1.6 CDI rough running on idle - light smoke on acceleration

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New Member
Oct 5, 2018
London, UK
E220 BlueTEC SE 2015
Any techs on here that can advise? I'm certain this is leaning towards injector 2 failure. The engine runs VERY lumpy at idle only and smokes lightly on higher rpms.

Shutting off injector 2 makes near to no change in roughness, but any other cylinder shutoff results in the idle becoming weak and extremely lumpy.

This is an OM626 1.6 CDI (Renault, yes I know), and what makes this worse is, the injector shop has said these are all fine!

The picture shows the injection quantities for each injector, what can you guys tell me from the values? I feel like cyl 4 is being overfuelled and cyl 2 is almost dead at idle.



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I had one with similar numbers the other day. To prove the point I swapped number one with number two, and the fault moved with it. A new injector resolved it. I think mine was at +5.20 ish. I’d ignore the number 4 for a while.
Are you able to do zero quantity calibration via xentry? I know it can be done on om651

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