C220 CDI W203 injectors

[techcareuk]

Hi, I have a 2003 C220 CDI t-wagon (estate) that has always smoked quite badly.
To give you a bit of background on the cars history I got the car in bad condition about 18 months ago, it was in M55 limp mode and once I took a closer look it obviously hadn't been looked after.
modifying the inlet manifold (removing the swirl flaps and plugging holes etc.) sorted the M55 limp mode problem, I also did the EGR omit mod ( the one with the circuit to manipulate the airflow sensor output when the EGR open signal is present to match the expected reduced flow values) which both improved the running and performance hugely but it has always suffered being smokey, some times worse than others but usually a constant puffing at idle and huge dark clouds at acceleration, I suspected prior to the car coming to me it had been run for a long time in limp mode and assumed it would improve with use, it did initially over the first month or so but it hasn't since.
I gave it two doses of Archoil 6400-D and 9100 which again helped but didn't cure.

Star is showing Quantity correction values of injectors as the following
Cyl1 5.3mm/3 Hub
Cyl3 -4.7mm/3 Hub
Cyl4 0.9mm/3 Hub
Cyl2 -4.2mm/3 Hub

It also shows current injected qty is 20mm/3 Hub (star shows expected value is 5.0-14.0)

looking at these figures I suspect injector at cyl1 definitely needs replacement but what about the others, do I need to be concerned with the injectors showing minus figures?

If cyl 1 is closest to the bulkhead then the injector in cyl4 appears to have been replaced with a new or recon unit before I got the car so i'm assuming the figure of 0.9mm/3 Hub is good?

and the big question, looking at these figures is it likely the injectors are the cause of the smoke?

Any advice would be very much appreciated.

 

[91dm]

What mileage has the car done?

How does the engine sound and does it tick over ok?

 

[techcareuk]

Thanks for the reply 91dm,

The car has currently done 185000 miles , I did an engine oil & Filter, fuel and air filter changes and new thermostat in December 2017 ( about 14000 of those miles have been done by me since December 2017).
it starts really well (really well even when icy cold) and idle's fine and although i've not heard many 611 engines to compare it to it appears to sound pretty healthy with no undue rattles or noise.
the turbo has a bit of a wine sometimes but you have to listen out for it to notice it.

 

[91dm]

Have you checked the MAF, has it ever gone into limp since the doing the flaps? At that mileage I would be tempted to pull all the injectors and have them bench test/refurbished.

 

[classiccarzone]

Do not be concerned with the injectors showing a minus value. This is an idle trim value and is done in the interest of smooth running. + or - 5 is within tolerances. Cylinder 1 is slightly above but not enough to warrant any action unless you are going for perfection.

If the quantity is way over what is expected then you should be looking at the quantity control valve and sensors on the rail and also at the pressure control valve.

Fuel Quantity Control Valve (FQCV)

also have a look at this:

Common Rail Injection System Pressure Control

MERCEDES BENZ FUEL PUMP PRESSURE REGULATOR CONTROL SOLENOID VALVE A6460740084 | eBay

I have a 2002 T-wagon and the valve at the back of the rail was causing smoking problems; but in my case it was also causing a fluctuating tick over.
Changed it with one that I knew was working well and all is good now.

You could try a little spray of releasing fluid on it but that only rarely works. Also check the wiring going to the socket on the valve. If the plastic cover on the valve is very lumpy it usually indicated that the solenoid is shot.

I always use Dipetane and find it excellent for freeing out and cleaning up fuel injection systems. I put a half a litre of Dipetane into no more than 20 litres of Diesel (or petrol) for an initial clean out and then use it at the recommended rate thereafter.

What is Dipetane and How Does it Work - Questions & Answers! | Dipetane

Start with the easiest things and don't jump to conclusions until you have sussed everything out.

 

[mersum1es]

2003 220 CDI has not fuel quantity valve...

As above change no1 injector first. Other minus values are settling down when positive correction is changed. But it usually does not cause heavy smoking.

Did you check your EGR is closed tight? No leaks in vacuum lines (egr and turbo control)? You may try swap the vacuum actuators between them and try if problem also jumps.

 

[classiccarzone]

When I googled the links I inadvertently put in Quantity instead of quality. Edited it at the time but it stayed the same

 

[techcareuk]

2003 220 CDI has not fuel quantity valve...

As above change no1 injector first. Other minus values are settling down when positive correction is changed. But it usually does not cause heavy smoking.

Did you check your EGR is closed tight? No leaks in vacuum lines (egr and turbo control)? You may try swap the vacuum actuators between them and try if problem also jumps.

EGR has been deleted/disabled and is closed with the vacuum blanked off

 

[techcareuk]

thanks everyone for your replies & clasiccarzone for your info, i'm weighing up if its going to be worth spending any more time and money on this as another problem has now developed , the turbo seems slow to spool up and after a few mins driving it throws a EPC error and into limp mode (3k rev restricted) addition to that its got front suspension ware so the list is groing......

to answer questions raised, the EGR has been disabled (its the early vaccum type) and the vacuum has been disconnected and blocked off and the mod to manipulate the MAF output then EGR open signal is present has been installed.

I have not investigated the MAF and it has never gone into limp after removing the swirl flaps and blocking the holes with bolts, The M55 motor was of cause left connected and cable tied to the rear bulkhead above the engine so it didnt get caught up in anything.
but to clarify the smoke problem has been there since I got the car and before the swirl flaps, M55 motor and EGR with mods were done.

I'll have to read it with Star and see if there are any codes to give an indication, last time I read it it showed an M55 code but I have a feeling that was thrown up by me unplugging it to check the connection so i'll have to read again.

 

[classiccarzone]

Have a look at this article. You may get some ideas

Sprinter Diesel Diagnostics | Oregon Fuel Injection