Hi guys, my C320 W204 with the om642 engine has developed a misfire on cylinder 6. She is knocking/clicking loudly and won’t idle properly its at 600rpm. I have replaced the injector that didn’t work and then the turbo because the vanes were seized and strangely pushing them down made the knock disappear? I have had star plugged im now and it’s said ‘number of combustion misfires at cylinder 6 too high’ and ‘check component N10/1kn relay which i have worked out is the fuel pump relay. It also basically said to test wiring between SAM and the ECU. Whilst I await a relay i am just curious what are people’s opinions about what this problem could be and what i should be looking at as im not convinced it is the relay. Cheers
Om642 misfire
- Thread starter Kev85
- Start date
Thanks for that
, just to clear this up, STAR said to check component N10/1Kn (engine circuit relay) and check wiring between SAM and component N3/9 (ecu) some googling tells me that the 1kn is fuel pump relay so im guessing that’s wrong? This is all very confusing for me.
as star says, it is engine circuit 87 relay (N) located in front SAM (N10/1). I just googled it too... Fuel pump relay is in rear SAM. Try change the relay N. Google may lead sometimes wrong because diesel car may have different fuse/relay assignment, but AFAIK fuel pump relay of 2000 onward models is always in rear SAM regardless of engine.
https://mbworld.org/forums/attachme...se-relay-box-left-side-engine-compartment.pdf
Edit; I remember a case mentioned where injector control component in ECU circuit had gone bad (every injector has 'a control bug' of its own).
https://mbworld.org/forums/attachme...se-relay-box-left-side-engine-compartment.pdf
Edit; I remember a case mentioned where injector control component in ECU circuit had gone bad (every injector has 'a control bug' of its own).
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Hi there
Thanks for the info, I tried replacing the relay to no avail the knock is still there. It’s been raining heavily where i am today and the water had gathered in a pool in the plastic surround for the wiper and was overflowing dripping onto the SAM cover and when i opened it up i could see it was wet at the back left corner of the unit not directly onto any fuses or relays but definitely on the wiring at the back below SAM. I have tried to upload pictures but it’s not working. Is it normal for water to gather in that wiper surround? I guess i need to inspect that wiring now Is it a difficult job to remove the SAM unit? Or would i be better getting an auto electrician to test it somehow?
Thanks for the info, I tried replacing the relay to no avail the knock is still there. It’s been raining heavily where i am today and the water had gathered in a pool in the plastic surround for the wiper and was overflowing dripping onto the SAM cover and when i opened it up i could see it was wet at the back left corner of the unit not directly onto any fuses or relays but definitely on the wiring at the back below SAM. I have tried to upload pictures but it’s not working. Is it normal for water to gather in that wiper surround? I guess i need to inspect that wiring now Is it a difficult job to remove the SAM unit? Or would i be better getting an auto electrician to test it somehow?
You must unblock the drains..
