C220 Cdi contribution issue P0269

[keanu]

After changing injector & fuel filter on a C220 cdi (as I had the P0269 DTC) it is still shuddering on idle and the injector (that cost £160!!) made no difference also the check engine light came back on yet again saying P0269.

I have now checked everything and happened to notice that when the fuel rail pressure sensor is unplugged the car runs 100% but cannot rev above 3000 rpm

I would change it but i doubt that it is the problem (and at £150 i didn't want to risk buying another useless part) because the DTC would surely indicate that the FRPS is at fault or at least have a contribution error to all 4 cylinders

even when plugged in the symptoms don't come back until i stop and start the engine again

i have also noticed that the engine has to be at normal running temperature before the shuddering starts

I have a video on YouTube to show exactly whats happening ( https://www.youtube.com/watch?v=nBMCzr_tWlQ&feature=youtu.be )

Any suggestions/advice would be greatly appreciated

Thanks in advance

 

[BlackC55]

Codes in this case are not going to help without live data.

Have a loom at my sticky in the engine section.

Also make sure the electrical plug is seated properly on the injector.

 

[keanu]

the plug is definitely seated properly but i have no idea what else to check everything else related to fueling seems to be fine i was hoping there was a common problem that i wasn't aware of but i cant find anyone who has had a problem even similar to mine :/

 

[mersum1es]

Is the replaced injector same part number than others? Injector leak off test done (both hot and cold), injector correction values checked (both hot and cold), cylinder compression test done?

What is model year of the car (type of the fuel system/injectors)?

 

[keanu]

its a 2004 C220 CDI 2.2l TD 4cyl the injector is the same part number as the others and if i swap it over to another cylinder it still throws up cyl 3 contribution fault which makes me think there was never a problem with the injector at all :/ after i clear it the code will stay away until the car gets up to temp and then comes back. has any one got any idea why unplugging the Fuel rail pressure sensor makes it idle perfectly

i am thinking that having it unplugged is making the fuel pump work 100% and the fuel pressure is higher so it could be a lazy pump?

 

[keanu]

i have not yet done a compression test and i will do a leak off tomorrow

 

[mersum1es]

Usually temp related shuddering is due to injectors or hp-pump. It might be jamming oil ring of the piston, and I remember one reported case where it was inlet valve which was jamming.

Unplugged pressure sensor gives constant value to ecu (and cause limp mode) and system is not trying to adjust altering pressure (real or just faulty signal). Me think problem is fuel pressure related...

 

[keanu]

if it was fuel pressure surely it would be on more than one cylinder do you think it would do any damage leaving the sensor unplugged for the tips to work and back over this week ? could it be the sensor that is faulty? as it is what tells the pump what pressure it needs

Thanks for your help so far guys

 

[keanu]

is there any decent Mercedes software i could download that would be better than/ more specific than scan xl i don't mind paying just want to get it sorted (owner is home today)

 

[BlackC55]

I would be inclined to do a compression check before anything.