Sprinter 311 2.2cdi, excess regen + white smoke + oil level rising

[tcourtneyvincent]

There isn't any balancing of gases to do.

During a regen the exhaust temp is usually controlled closed loop, ie not hot enough, increase the post injection quantity, too hot, reduce post injection quantity. If that exothermic reaction isn't happening it would ramp up those post injections trying to get it hot.

Used to see problems with old transits that didn't exotherm. They had both bricks in the same can. There was a temp sensor on the inlet and mid way on the can.

Do you know why the reaction wasn't happening for these?

 

[Supernoodle]

I'm pretty sure it's labeled as "position" on the icarsoft

Unplug MAF. What does it show for EGR then? When MAF is in fault it should keep EGR closed, so if still 5%, that does mean closed.

 

[Supernoodle]

Do you know why the reaction wasn't happening for these?

They were all high milers.

 

[tcourtneyvincent]

Unplug MAF. What does it show for EGR then? When MAF is in fault it should keep EGR closed, so if still 5%, that does mean closed.

This is with the mass air flow unplugged. Both the EGR and Wastegate are glued to this value even with revs. So I guess this is there totally shut potition

 

[tcourtneyvincent]

This is with the mass air flow unplugged. Both the EGR and Wastegate are glued to this value even with revs. So I guess this is there totally shut potition

Altho actually, the wastegate at this low value is actually totally open, bypassing all the boost. The boost pressure barely fluxuates with revs. Is there any chance the EGR could be in reverse? And 5% actually means totally open?

 

[Supernoodle]

Altho actually, the wastegate at this low value is actually totally open, bypassing all the boost. The boost pressure barely fluxuates with revs. Is there any chance the EGR could be in reverse? And 5% actually means totally open?

It's def EGR closed.

You can calculate an approx air flow figure for a diesel as they aren't throttled

Volume of theoretical air per second in cm3 is

Cyl vol[cm3] x RPM x no. of cyl/ (2 x 60)

Convert that volume to a mass assuming

Density of air @15degC in g/cm3 is 1.225 x10^-3

For a 2 litre at 849 rpm

549x 849 x 4 / (2 x 60) = 15536cm3/s

Multiply by density

1.225 x 10^-3 x 14150 = 19. 03g/s

That's theoretical, so assuming the engine has a volumetric efficiency of 80% gives

19.03 x 0.8 =15. 2g/s

To convert to mg/stroke

15.2g/s x1000 =15200 mg/s

x60= 912000 mg/min

/ 849rpm =1074.2mg/rev

/2 = 537mg/stroke (2 working strokes per cycle)

That's the same number you see on icarsoft. If EGR was fully open you'd expect to see half that figure.

 

[tcourtneyvincent]

It's def EGR closed.

You can calculate an approx air flow figure for a diesel as they aren't throttled

Volume of theoretical air per second in cm3 is

Cyl vol[cm3] x RPM x no. of cyl/ (2 x 60)

Convert that volume to a mass assuming

Density of air @15degC in g/cm3 is 1.225 x10^-3

For a 2 litre at 849 rpm

549x 849 x 4 / (2 x 60) = 15536cm3/s

Multiply by density

1.225 x 10^-3 x 14150 = 19. 03g/s

That's theoretical, so assuming the engine has a volumetric efficiency of 80% gives

19.03 x 0.8 =15. 2g/s

To convert to mg/stroke

15.2g/s x1000 =15200 mg/s

x60= 912000 mg/min

/ 849rpm =1074.2mg/rev

/2 = 537mg/stroke (2 working strokes per cycle)

That's the same number you see on icarsoft. If EGR was fully open you'd expect to see half that figure.

Wow, nice one, makes total sense! You really seem to know your stuff! Do you have any hunches or ideas of what to do next in my position?

 

[Smart320]

Train as a mathematician

 

[Supernoodle]

If it's def only regen that's a problem I'd be suspecting the DOC. You've got the mileage I've seen probs on other brands, but I don't know the Merc DPFs that well. Assuming the DOC is that other cat you say has been replaced with a non genuine part, that's suspicious.

I would expect this to be sonething that got gradually worse. Did it? Or haven't you owned it long enough?

If it was direct from Royal Mail, no chance someone tinkering and putting on some dodgy remap. Or was there another owner?

 

[Planefix7015]

Hi - Read this whole thread with interest.

The same vehicle on a 2009 LWB 311 2.2 CDI

My symptoms are exactly the same as yours in regards to the white smoke, engine note, oil level increasing, drop in performance (well compared to what little it has anyway!) stinks of fuel + massive drain of fuel rate - seems to regen for about 50 / 60 miles on the motorway sometimes more (i often drive Manchester to Oxford) and burns a ton of fuel ......... then goes like a rocket for the next few hundreds miles - then repeats!

Mine also regens when cold, like yours ...... and seems to get stuck in a regen loop almost

I do have a low boost pressure fault as well - my turbo vanes are stiff and the turbo needs a rebuild as a result, but this is unrelated to the issue I'm certain as when its been doing the smoke screen game - I've even disconnected the turbo actuator and tried it fully in the open or closed position and it makes zero difference.

I have an Autel MK808 and ive played around with n other codes showing and similar figures - i.e DPF not showing blocked etc ........

I'm convinced its something simple, but unless i now start to chuck parts at it in the hope i fix it I'm also at a loss ..... I've checked all the obvious stuff, hoses and the like

Cheers
Dave