E350 CDI Rough idle when cold

[shady007]

Hi everyone
Recently got 2009 E350 CDI coupe and I am struggling to find out why engine is idling rough when cold. Maybe someone here can give any advice..
The garage initially was saying bad EGR valve.. values going over 100%. Replaced EGR.. values within tolerance but still running rough when cold. After driving 50 or so miles after flooring got check engine light, P0404 range/performance problem of egr.
Was thinking the replacement part was faulty (ebay one). Decided to unplug the egr one night and car was idling perfectly fine apart from obvious two error codes because of unplugging...
Maybe coincidence or not.. since driving with unplugged egr in limp mode idle was perfect all the time. So decided to delete egr.. and problem came back after deletion.. runs lumpy and rough when cold. Around 60-70c gets a lot better and completely smooth at around 80.
I have also replaced air filter, fuel filter and did put in diesel cleaner. No other errors coming up.
Also I havent put blanking plate on, maybe the valve is stuck open since reflashing ecu? To my logic it should stay closed.
Thanks

 

[suty455]

How did you delete the EGR?
Mine has no EGR/DPF and a custom intercooler and exhaust and runs the same now as it always has in terms of tickover etc apart from the aggravating DPF cleans which causes high idles, it also idles high when its cold but that is normal once warm drops to about 600 rpm, can only suggest get it to a proper remap place who can look at whats happening on a rolling road, no rolling road dont waste your time they just install an off the shelf map thats no better than the factory one each car is slightly different a proper remap will cater for it, yours should give about 265 reliably once done.
Swirl flaps cause issues on these as does the turbo manifold to air intake seal and the pcv valve seal both are service items and really should be changed if removed a couple of times, check the swirl flap motors and connections they sit under the turbo intake and oil seeps out of the pipe and kills the connections.
If the car has had a lot of town driving I suspect a good intake clean will be worthwhile

 

[Larkone]

Hi everyone
Recently got 2009 E350 CDI coupe and I am struggling to find out why engine is idling rough when cold. Maybe someone here can give any advice..
The garage initially was saying bad EGR valve.. values going over 100%. Replaced EGR.. values within tolerance but still running rough when cold. After driving 50 or so miles after flooring got check engine light, P0404 range/performance problem of egr.
Was thinking the replacement part was faulty (ebay one). Decided to unplug the egr one night and car was idling perfectly fine apart from obvious two error codes because of unplugging...
Maybe coincidence or not.. since driving with unplugged egr in limp mode idle was perfect all the time. So decided to delete egr.. and problem came back after deletion.. runs lumpy and rough when cold. Around 60-70c gets a lot better and completely smooth at around 80.
I have also replaced air filter, fuel filter and did put in diesel cleaner. No other errors coming up.
Also I havent put blanking plate on, maybe the valve is stuck open since reflashing ecu? To my logic it should stay closed.
Thanks

AIUI you cannot use an EGR blanking plate on these engines. Whoever deleted your EGR in the software should have checked that it was in the closed position in their code reader and that it did not open under any throttle opening. Possibly your swirl flaps / inlet manifold are coked up.

 

[88Adam88]

Hello did you find the problem? Thanks