C220 w204 2007 auto qcv fuel pressure,issue esp ,mil idle rough , fuel pressure high problem solved


New Member
Mar 19, 2022
C220 w204 2007
Hi guys
I had bought a c220 w204 cdi automatic 2.2 saloon diesel
And experienced a headache of an issue which turned out to be the qcv quality control valve fuel valve
Below are symptoms
Poor idle power flatspots
Esp mil light on when foot down hard
Idle fluctuation 0.7 to 0.9 revs
With vibration at idle together
Engine 1-2 seconds gushing noise
Juddering at high speed
Engine cuts out at lights and dips below
Poor mileage , lazy start
Oil leak , fuel injectors leak
Black smoke with fumes in vent

Obd delphi scanned fault first
High fuel pressure detected
Fuel tempeature sensor fault detected

Parts used in tracing faults 2nd hand (some )
Cleaned egr, new fuel filter
New fuel temp sensor , 2nd hand high pressure pump , new fuel injector seals ,
New rocker gasket set , 2nd hand fuel pressure rail with pressure relief valve on one side and fuel pressure sensor on other as i was advised by mechanic as this is the culprit but he was wrong

I replaced all above items thinking it was these until i replaced the qcv quality contol valve pcv on the pressure pump at front with a solenoid on its 2 bolt t25 torx easy access and a 2 pin connection
It was part number A6460740384
After a month of throwing money at the c220 and a headache it turned out to be the quality control valve high pressure component which caused the high pressure fault at the end
Thanks for reading
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