NCV3 DPF Blocked

Dieselhawk

New member
Hi Guys,
I have a 2008 311CDI with approx. 110,000km on the clock. Its never missed a beat up until last week when I noticed a miss on hard acceleration and it stalled twice, funnily enough both times as I pulled into the Mercedes dealer to pick up parts for another vehicle (I am a diesel mechanic myself). I noticed it was down on power and it brought the check engine light on. It slowly got worse over a day or so until I took off the next morning and it was totally gutless to the point that I had to pull over and get towed. It now had the check engine light flashing. I replaced the fuel filter but made no difference.
It has now been in the Merc dealer for 4 days. I decided to take it straight there as I didn't have the software required or anything that would read the codes. I work on bigger stuff Detroit, Cat, Cummins etc
First I was told the only relevant stored code was low boost or similar.
They thought I had put biodiesel or some poor quality diesel in (which I hadn't) so they replaced the fuel in the tank but this made no difference.
When I called this morning they now tell me the only active code is relating to the DPF but this wouldn't cause the problem. This sounded a bit funny to me so I did a quick search and found this

Below are some of the most common problems when the dpf fails on a Mercedes Sprinter.
Loss of power / no throttle response
Engine/DPF warning lights on dash
Poor fuel consumption
Hard to start and slow pickup speed
Limp mode (wont rev over 3000rpm)
Engine starts and cuts out
Engine fails to starts


I have all these symptoms bar the poor economy and failing to start. Since then they disconnected the DPF and the engine now runs fine in the shop. But they still say they don't know if its the DPF or Cat so are removing one off another vehicle to try it.
Now it doesn't look like "rocket surgery" to me but I just wanted a few opinions before I go in with a tilt tray tomorrow and drag the thing back to my own workshop.
I have asked twice for the price on a new DPF but they are reluctant to give it to me. I have found a local company that clean them so will probably go with that.
The bill for 4 days of scratching their heads/nuts will be the next hurdle.:yell:

Cheers, any advice or comments much appreciated.

PS Currently downloading diagnosis software so this never has to happen again!
 

parcelpeter

New member
Get them to try a regeneration on the dpf with the computer or try to regenerate it yourself by driving on a dual carriage-way or motorway for 20-45 mins in 4th gear at 2000RPM to initiate a regeneration.You will know its regenerating by the smoke.
Ive had mine deleted cause of the work i do with the van,start stop all the time and dpfs hate that.
 

Dieselhawk

New member
Thanks parcelpeter,
The van won't even run with the DPF connected at the moment but they might be able to do it in the shop. I'll ask the question. Cheers.
 

lindenengineering

Well-known member
Talking about these filters I have just taken one off a TOTALLY plugged up 2008 CRD.

Not only is the induction and EGR side blocked up with carbon but so is the exhaust!
AND this was driven from "Nu Joisey" to Denver!:hmmm: Persistant owner for sure!:laughing:

Well I did fling it to a guy who cleans these things in Denver but he couldn't get it totally clean. So its going to be a new one. Ouchie!

Anyway if yours needs cleaning AND its not totally plugged up and beyond redemption then sent it to Riley @Intermountain Radiator And Muffler tel; 720, 581, 5004.

Dennis
 

lindenengineering

Well-known member
Post Addendum
Just so you folks are wondering JUST how much is a DPF filter; $2690 is the quote from MB here in Denver----Just beer money I suppose!:idunno:
Dennis
 
Dennis

How much is Riley to clean it? Ballpark on a 75% plugged unit.
 

lindenengineering

Well-known member
His standard charge is $300.
That stated it wasn't successful on the bad boy I gave him on Monday, he could only get it 50% cleaned so it was $150.

Dennis
 

BBlessing

61k happy miles
this tale is cause to keep your foot out of the throttle. drive them as easy as possible to keep this type of thing from happening.

bb
 

sailquik

Well-known member
BBlessing,
My experience with NCV3's with DPF (granted they were 2010 or later Mercedes Benz, not Dodge or Freightliner) is pretty much the opposite.
Keep some revs on them >2400 for sure, and a few times per day "blow them out" with heavy acceleration to get the temps up and revs over 3000.
Works for me!
Roger
 
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BBlessing

61k happy miles
Bill,
My experience with NCV3's with DPF (granted they were 2010 or later Mercedes Benz, not Dodge or Freightliner) is pretty much the opposite.
Keep some revs on them >2400 for sure, and a few times per day "blow them out" with heavy acceleration to get the temps up and revs over 3000.
Works for me!
Roger
I don't know who bill is. anyhow, what I was getting at, is that putting your foot in it at low rpms is what is plugging up the dpf. yes high rpm driving is good for clearing out things, but it is good or better to get there gently.

bruce blessing
 

CJPJ

2008 3500 170"ext. 3.0 V6 OM642.993
and a few times per day "blow them out" with heavy acceleration to get the temps up
Works for me!
Roger
Heavy acceleration produces more soot and is Counter productive to unblocking a DPF! "heavy acceleration to get the temps up" Not needed! Regenerations will start fine with 40 miles per hour exhaust temperatures, then the engine management will increase exhaust temperature through late fuel injection.

If you ever watched the exhaust stack of a pre 2007 diesel , pre being before Diesel partial Filters. They belch soot. A lot of the time it's noticeable when the operator has there foot in it going through the RPM's accelerating. Once up to speed the exhaust clears up. Black soot collects in the DPF and is filling it until the soot triggers a regeneration. The regeneration cleans the DPF but not 100% eventually the filter dies. So driving around avoiding the heavy soot instances has got to extend the time duration between the regenerations and extend the life of the DPF.
anyhow, what I was getting at, is that putting your foot in it at low rpms is what is plugging up the dpf. yes high rpm driving is good for clearing out things, but it is good or better to get there gently.

bruce blessing
X 2
 
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shanemac

Active member
Is there a low tech easy way to tell if the DPF is starting to plug without pulling the DPF off, is there a metric/baseline of exhaust air flow out tail pipe at idle?
 

dukepilot

Custom Spooling USA
Is there a low tech easy way to tell if the DPF is starting to plug without pulling the DPF off, is there a metric/baseline of exhaust air flow out tail pipe at idle?
Not low tech but you can read/monitor exhaust pressure differential at the DPF with a good scan tool (MB Star, Diagun, AutoEnginuity w/enhanced package). What's missing are the numbers/values that would tell you when the pressure differential is too great, triggering a regen or limp mode/trouble code.
 

Dingo

New member
Why the F%$£ don't the manufacturers just fit an injector into the exhaust downstream of the turbo to burn out the DPF . This would stop overfuelling washing bores dry of oil & wrecking engines . Would reduce wasted fuel as only one injector is "wasting fuel" .

If you want to increase exhaust gas temps , simply driev in a lower gear than normal & the increase in load will raise the temp . My van does not have all this tehcnical ****e fitted , but i do wind the revs up towards the red line every so often & i am amazed by the cloud of junk blown from the tail pipe . My previous 312 spent all its life working on the motorway ( highway)
virtually , it rarely chucked any soot out when pushed hard .

I put this down to complete combustion & high gas temps / high gas speeds clearing the pipes
 

flman

Making Turbo Cry!
I have heard, you can drill a 3/8" hole through the DPF core and it will run OK, and the computer will think every thing is just fine?
 

showkey

Well-known member
Soot is not the only problem...........

Think there can be two or more things that can cause a DPF problem:

Soot that should be cleaned with regen when the systems works as designed and use allows full regen at a regular needed interval.

Clogging due ash and other contaminates from the oil or fuel will not removed by regen. This can happen over time usually higher mileage.

If there is another engine mechanical problem it can easily damage or plug the DPF.......especially oil consumption. Regen will not solve or replacing the DPF without correcting the root cause future disappointment.
A side note gas engines also experience catalyst damage from oil consumption, misfire, also oil ingredients in gas engine has been changed to prevent cat fouling.......from zinc etc

There has been a lot written on DPF and apply to all clean diesels.

http://www.worktruckonline.com/chan...-about-diesel-particulate-filters/page/2.aspx
 
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lindenengineering

Well-known member
Soot is not the only problem...........

Think there can be two or more things that can cause a DPF problem:

Soot that should be cleaned with regen when the systems works as designed and use allows full regen at a regular needed interval.

Clogging due ash and other contaminates from the oil or fuel will not removed by regen. This can happen over time usually higher mileage.
There has been a lot written on DPF and apply to all clean diesels.

http://www.worktruckonline.com/chan...-about-diesel-particulate-filters/page/2.aspx
I will strongly endorse the above.
Every one I have seen choked up of late has not been run on the right oil!

The big concern of course is fuel quality, a factor that is hard to overcome due to the huge variation across the US.
On a Ford factory tech course I attended recently this was a major source of discussion and debate.
Dennis
 

CJPJ

2008 3500 170"ext. 3.0 V6 OM642.993
Is there a low tech easy way to tell if the DPF is starting to plug without pulling the DPF off, is there a metric/baseline of exhaust air flow out tail pipe at idle?
Not low tech but you can read/monitor exhaust pressure differential at the DPF with a good scan tool (MB Star, Diagun, AutoEnginuity w/enhanced package). What's missing are the numbers/values that would tell you when the pressure differential is too great, triggering a regen or limp mode/trouble code.
I do recall a thread (couldn't find it with search) where the members were tracking the regeneration's : frequency , regen temperatures , elapse time.

I wish that I could tell how frequent (in miles) that the regeneration's do take place. I can:shifty:not tell, it's likely due to the good job I did insulating the van as it is relatively quiet to drive.
 
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I was with CJPJ, couldnt tell when it regen'd until about a month ago while waiting in my van for something and playing with my ultragauge and noticing that it in fact does have the CAT1 and CAT2 temps. I put them on the front screen and it works great. I roll down the highway averaging 500-700 degrees. When the awful moment comes when it regens it shoots up the CAT2 to around 1300 degrees, engine temp rises 10 degrees as well. It took about 20 minutes the last time I noticed for it to finish at 62MPH.
 

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