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View Full Version : Mercedes Cclass W204 fault !



dave11674
24th September, 2017, 08:53 PM
Hi guys wondering if you can shed some light. Tuned my c class merc w204 2008
Every now and again i get limp mode and engine management light on. Cycling ignition brings it back out of limp. These are the 2 fault codes showing bit contradicting so maybe a faulty fuel pressure regulator !! If so does anyone know where it is and how easy to change.
Ive noticed right before this happens i get a bit of a judder from the engine
ive put orig file back in but still happens.

Thanks

Dariusz
24th September, 2017, 09:40 PM
Check the diesel injector

dave11674
24th September, 2017, 10:15 PM
Is this one part or the lot ?
you mean check injectors mate ?

Dariusz
24th September, 2017, 10:23 PM
The amount of return fuel from the injectors.

dave11674
25th September, 2017, 07:07 PM
how to check
pull off teh black pipes and see what is returned ?

dave

Mario3
25th September, 2017, 10:04 PM
Since you have a fault of "pressure to big" it cant be the returnflow on the injectors. I would go for the regulator in the rail (its the one on the end upper in your pic, the other is the fuel pressure sensor)

regards

dave11674
24th October, 2017, 10:35 PM
ok guys i finally got this sorted

bought a use and assured working QCV (top sensor)
replaced it
car was warm when we did it and i was driving here n there the rest of the day so was warm all day and no limp or faults popped up
so thought it was fixed.

unit i came to it Sunday morning cold start, oh my the engine was revving up and down like it was gasping for fuel
engine was like shuddering from side to side
thought it was broken
so i drove it to my job, and when it warmed up the shuddering and bad running went away !!!

so thought fluff this
i and spoke to a mercedes man i know, he said change fuel filter.
so on monday i went round to mates garage, put orig QCV back on and changed the fuel filter.
we didnt tip the fuel from the old filter into this new one as it could of had shitty fuel in it.

cycled the ignition a few times, and was presented now with what sounded like an air leak when we turned on the ignition, in the T piece in the return line..
i said to my mate i bet its just how it expels air out the system.
anyways it fired straight up so i went about my business

this morning my car fired up and purred like a pussy
not a murmer
not a ESP light on the dash all day and i was out doing lots of calls today
usually get it 3 or 4 times a day

so i think all along it was the fuel filter was a little shitty :)

thanks for any pointers here guys

dave

dave11674
26th October, 2017, 06:56 PM
ahhh take it back, went into limp again today lol

time to bust out start diagnostics i think heheh

lush29
26th October, 2017, 08:05 PM
ahhh take it back, went into limp again today lol

time to bust out start diagnostics i think heheh

I did dpf and egr in an w204 and i get some fuel presure fault also, client said that to me and some times limpmode. Car comes in tmrw... i will check but think is my have to do with the maps in my situation


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dave11674
2nd November, 2017, 09:46 PM
keep us informed mate

thanks

dave

dave11674
18th November, 2017, 03:42 PM
lush did you get this sorted mate ?

dave

lush29
19th November, 2017, 02:22 AM
lush did you get this sorted mate ?

dave

Sorry dave, just seen this i did yes.i blocked egr and all back to nornal


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dave11674
28th November, 2017, 11:14 AM
hmmm
you a pointer to where egr is on mine ?

dave
thanks