Fuel Economy Falling, DPF issue?
Thread Starter
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Joined: Jun 2012
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S203
Fuel Economy Falling, DPF issue?
Hello, I am drving a 2005 C220 CDi with 98,000 on odo. Has been serviced on the button with correct lubes (Mobil 1 ESP). I am seeing MPG dropping - now 10-15% down on historic. It gets lots of gentle drives then regular long drives on motorway.
I had warning light come on diagnosed as P2626 - which I think is DPF full. Reset light which has not come on again. However fuel economy still dropping with no other fault codes. Only other recent changes are fuel filter (at around time MPG started to drop - was 40MPG now closer to 34 MPG).
Am I right in thinking that DPF is now full?
Would blocked DPF reduce MPG - seems logical?
Why no reapperance of warning light?
Do DPFs have finite life (mine close to 100,000)?
Any experiences of:
a) additives and blast on motorway?
b) garage clean of DPF?
c) professional clean on DPF?
d) aftermarekt DPFs?
e) remove and delete DPF?
Lots to take in but I hope this will be useful to others too.
Mat
I had warning light come on diagnosed as P2626 - which I think is DPF full. Reset light which has not come on again. However fuel economy still dropping with no other fault codes. Only other recent changes are fuel filter (at around time MPG started to drop - was 40MPG now closer to 34 MPG).
Am I right in thinking that DPF is now full?
Would blocked DPF reduce MPG - seems logical?
Why no reapperance of warning light?
Do DPFs have finite life (mine close to 100,000)?
Any experiences of:
a) additives and blast on motorway?
b) garage clean of DPF?
c) professional clean on DPF?
d) aftermarekt DPFs?
e) remove and delete DPF?
Lots to take in but I hope this will be useful to others too.
Mat
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
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From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Hello, I am drving a 2005 C220 CDi with 98,000 on odo. Has been serviced on the button with correct lubes (Mobil 1 ESP). I am seeing MPG dropping - now 10-15% down on historic. It gets lots of gentle drives then regular long drives on motorway.
I had warning light come on diagnosed as P2626 - which I think is DPF full. Reset light which has not come on again. However fuel economy still dropping with no other fault codes. Only other recent changes are fuel filter (at around time MPG started to drop - was 40MPG now closer to 34 MPG).
Am I right in thinking that DPF is now full?
Would blocked DPF reduce MPG - seems logical?
Why no reapperance of warning light?
Do DPFs have finite life (mine close to 100,000)?
Any experiences of:
a) additives and blast on motorway?
b) garage clean of DPF?
c) professional clean on DPF?
d) aftermarekt DPFs?
e) remove and delete DPF?
Lots to take in but I hope this will be useful to others too.
Mat
I had warning light come on diagnosed as P2626 - which I think is DPF full. Reset light which has not come on again. However fuel economy still dropping with no other fault codes. Only other recent changes are fuel filter (at around time MPG started to drop - was 40MPG now closer to 34 MPG).
Am I right in thinking that DPF is now full?
Would blocked DPF reduce MPG - seems logical?
Why no reapperance of warning light?
Do DPFs have finite life (mine close to 100,000)?
Any experiences of:
a) additives and blast on motorway?
b) garage clean of DPF?
c) professional clean on DPF?
d) aftermarekt DPFs?
e) remove and delete DPF?
Lots to take in but I hope this will be useful to others too.
Mat
Was the fuel filter the correct MB part ? Just a thought .
There are catalytic convertors in your exhaust which may be also hindering the flow.
Do you notice whether your DPF is regenerating at regular intervals ? . IE burning off smell.
How is the cars performance . Is there any power loss?
"Common issues are jammed turbo vanes, air flow sensors, EGR valve blocked, boost pressure sensor faults or vacuum leak to the turbo control valve or damaged intake manifold flaps." source Ausmbtec on this site.
I have heard of people cleaning DPF's whth high pressure cleaners but do not know of the outcome.
Many moons ago there were industrial carbon remover chemicals which I used to clean marine diesel exhaust valves but I do not know whether they are still available or if they would damage the DPF.
Removal of the obnoxious thing would be the answer but you would have to consider the local laws & the calibration of the differential pressure sensors.
You may receive more help on the MB World Diesel Forum.
I would be interested to know the outcome.
JC
Member
Joined: Nov 2010
Posts: 197
Likes: 1
From: Australia
C220 CDI SLK 200
Hello, I am drving a 2005 C220 CDi with 98,000 on odo. Has been serviced on the button with correct lubes (Mobil 1 ESP). I am seeing MPG dropping - now 10-15% down on historic. It gets lots of gentle drives then regular long drives on motorway.
I had warning light come on diagnosed as P2626 - which I think is DPF full. Reset light which has not come on again. However fuel economy still dropping with no other fault codes. Only other recent changes are fuel filter (at around time MPG started to drop - was 40MPG now closer to 34 MPG).
Am I right in thinking that DPF is now full?
Would blocked DPF reduce MPG - seems logical?
Why no reapperance of warning light?
Do DPFs have finite life (mine close to 100,000)?
Any experiences of:
a) additives and blast on motorway?
b) garage clean of DPF?
c) professional clean on DPF?
d) aftermarekt DPFs?
e) remove and delete DPF?
Lots to take in but I hope this will be useful to others too.
Mat
I had warning light come on diagnosed as P2626 - which I think is DPF full. Reset light which has not come on again. However fuel economy still dropping with no other fault codes. Only other recent changes are fuel filter (at around time MPG started to drop - was 40MPG now closer to 34 MPG).
Am I right in thinking that DPF is now full?
Would blocked DPF reduce MPG - seems logical?
Why no reapperance of warning light?
Do DPFs have finite life (mine close to 100,000)?
Any experiences of:
a) additives and blast on motorway?
b) garage clean of DPF?
c) professional clean on DPF?
d) aftermarekt DPFs?
e) remove and delete DPF?
Lots to take in but I hope this will be useful to others too.
Mat
On advice from my MB mechanic I have found that when my fuel economy is dropping I go for long drive and immediately my economy increases by about 10-15%
Thread Starter
Newbie
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S203
Fuel Economy Dropping DPF blocked?
Thank you both, I have tried long drives >100 miles at 2000 RPM still not good economy, but I noted the % drop in MPG was less on the motorway compared to usual routes. Usual routes were slightly better but could be coincidence. I suspect that I shall have to try another garage and I am bracing myself for DPF clean/removal/replacement.
I am not sure DPF removal is good idea - could it cause other issues?
Mat
I am not sure DPF removal is good idea - could it cause other issues?
Mat
Member
Joined: Nov 2010
Posts: 197
Likes: 1
From: Australia
C220 CDI SLK 200
Thank you both, I have tried long drives >100 miles at 2000 RPM still not good economy, but I noted the % drop in MPG was less on the motorway compared to usual routes. Usual routes were slightly better but could be coincidence. I suspect that I shall have to try another garage and I am bracing myself for DPF clean/removal/replacement.
I am not sure DPF removal is good idea - could it cause other issues?
Mat
I am not sure DPF removal is good idea - could it cause other issues?
Mat
1 Drag ie incorrect tire pressure
2 incorrect fuel air mix
3 poor disposal of waste products
1 is easily checked
2 ECU problems, air filter, injectors, turbine, turbine control ETC and sensors lambda sensor perhaps even the wrong oil?
3 Particulate filter exhaust leakage
Last week I noticed my oil burner was not running properly so I went on a 400 mile quick drive. all come back to normal
http://www.lambdapower.co.uk/TechNotes/Tech-12.asp
read this it may give you more insight
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Thanks for the Lamba link. Very interesting & filed way.
What do you think clogs up on your 220CDI to cause your problem?
Do you have a DPF ?
JC
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Thank you both, I have tried long drives >100 miles at 2000 RPM still not good economy, but I noted the % drop in MPG was less on the motorway compared to usual routes. Usual routes were slightly better but could be coincidence. I suspect that I shall have to try another garage and I am bracing myself for DPF clean/removal/replacement.
I am not sure DPF removal is good idea - could it cause other issues?
Mat
I am not sure DPF removal is good idea - could it cause other issues?
Mat
Take a look at this process :- http://www.otctools.com/products/www...er_Cleaner.com
Removal of the DPF would need some homework done regarding local pollution laws & making sure the sensors on the DPF are programed correctly so no regeneration will take place in advertently.
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Member
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From: Australia
C220 CDI SLK 200
Quote
The remaining particulates still made by the Diesel engine are trapped in filters located in the exhaust system, called particulate filters. Obviously, given time these filters will clog up and require cleaning. This is done under the control of the ECU and is termed "filter regeneration". Diesel exhaust because of its inherent thermal efficiency is not hot enough to oxidise the soot that has been collected on the filters, so the ECU opens the injector again right at the end of the combustion cycle, thus allowing unburned fuel to enter the exhaust system. This happens occasionally (approximately every 500-1000km) during steady cruising conditions, the fuel ignites in the hot exhaust and raises the temperature to about 650 degrees C, above the oxidation point of the soot. This completes the combustion within the filter, oxidising the soot particles and thus cleaning the filter. The soot particles are liberated from the filter, are carried out of the exhaust along with the normal exhaust gas flow, and discharged into the atmosphere.
Last edited by Big Daddy; Jan 28, 2013 at 01:03 AM.
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MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
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From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Thanks BD.I am lucky enough not to have a DPF so have not encounted this issue.
If I catch the turbo out when accellerating I leave a trail of black smoke.
My 220CDI was built in late 2007 & has two cats only.
If I catch the turbo out when accellerating I leave a trail of black smoke.
My 220CDI was built in late 2007 & has two cats only.
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Joined: Jun 2008
Posts: 19,942
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Don't forget the other items Ausmbtech stated, most of which are air related.
And don't forget Cats. These vehicles do clog their cats in certain service/age. EGR valves clog more often than one might think as well.
EDIT: a bad 02/lambda sensor should throw a code.
So yes it's all about air into the engine/exhaust gas out of the engine & proper fuel metering.
And don't forget Cats. These vehicles do clog their cats in certain service/age. EGR valves clog more often than one might think as well.
EDIT: a bad 02/lambda sensor should throw a code.
So yes it's all about air into the engine/exhaust gas out of the engine & proper fuel metering.
Last edited by Glyn M Ruck; Jan 28, 2013 at 07:05 AM.
Thread Starter
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S203
Partial Update
Hello all and thank you for responding.
I changed air filter in Jan as that was my first thought. No real difference. Tyres are checked weekly.
My journeys are mainly 45 mins but at gentle throttle - 1300-1800 RPM (it is an auto so hard to thrash).
I am going to get a second opinion tomorrow so may know more. I hope to get a readout of pressure differential across DPF at idle and say 2000 RPM (but not actually moving) maybe I will get an airflow reading from MAF sensor and see if that is in spec - as they drift out of spec over time. Depending on that I may chuck in some DPF cleaner and take for a good long motorway thrash but knocked down a cog. Otherwise I shall examine and clean EGR in case stuck/sticking open.
One thing I did notice was that from cold start up the MPG drops from about 40MPG down to close to 30MPG over first 4-5 miles or so and then gradually recovers. I got it up to 38 MPG average over a 22 mile run lasting 45 mins today. But I was driving like I was carrying nitro-glycerine! I wonder if this profile gives a clue to a warm up/temperature sensing issues (maybe cold weather and colder starts do not help).
Any ideas let me know. If I get any good info tomorrow I shall let you know.
Incidentally I was quoted £600-£800 for DPF removal and ECU delete, almost half as bad a a new DPF. Alternative may be an ultrasonic/solvent clean at £200 plus removal/refit.
Mat
I changed air filter in Jan as that was my first thought. No real difference. Tyres are checked weekly.
My journeys are mainly 45 mins but at gentle throttle - 1300-1800 RPM (it is an auto so hard to thrash).
I am going to get a second opinion tomorrow so may know more. I hope to get a readout of pressure differential across DPF at idle and say 2000 RPM (but not actually moving) maybe I will get an airflow reading from MAF sensor and see if that is in spec - as they drift out of spec over time. Depending on that I may chuck in some DPF cleaner and take for a good long motorway thrash but knocked down a cog. Otherwise I shall examine and clean EGR in case stuck/sticking open.
One thing I did notice was that from cold start up the MPG drops from about 40MPG down to close to 30MPG over first 4-5 miles or so and then gradually recovers. I got it up to 38 MPG average over a 22 mile run lasting 45 mins today. But I was driving like I was carrying nitro-glycerine! I wonder if this profile gives a clue to a warm up/temperature sensing issues (maybe cold weather and colder starts do not help).
Any ideas let me know. If I get any good info tomorrow I shall let you know.
Incidentally I was quoted £600-£800 for DPF removal and ECU delete, almost half as bad a a new DPF. Alternative may be an ultrasonic/solvent clean at £200 plus removal/refit.
Mat
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E320 Estate for wafting and M3 SMG for blasting!
I know this is probably sorted now, but one thing to remember about DPF is they will only regenerate when the car gets to full temperature, problem with that is most take the reading from the thermostat and wait to hit 90ºc, however, most thermostats start to fail after 4 or 5 years.
Always keep an eye on your thermostat temperature, if it is not getting above 80 odd replace it, for a start the ecu overfuels, a lot when only getting to 70ºc and still a fair amount at 80ºc, but also the dpf will never regenerate and will get blocked.
A few guys on the BMW forum have been told they needed new DPF fitted, but then swapped their thermostats and the car suddenly regens and they are good for another 100k miles.
Thermostat needs to be a serviceable part now imho, at least checked every year.
Always keep an eye on your thermostat temperature, if it is not getting above 80 odd replace it, for a start the ecu overfuels, a lot when only getting to 70ºc and still a fair amount at 80ºc, but also the dpf will never regenerate and will get blocked.
A few guys on the BMW forum have been told they needed new DPF fitted, but then swapped their thermostats and the car suddenly regens and they are good for another 100k miles.
Thermostat needs to be a serviceable part now imho, at least checked every year.
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S203
I think you are on to something
Hello and thank you, I have noticed that fuel economy is better on warmer days than colder ones - over a regular commute same route to work at same average MPH. The dash indicates temp below half consistently and I was wondering about thermostat or possibly (if thermostat is ok) the MAF sensor (which works on temperature I believe). I shall get this checked out and post an update.
Incidentally, I got a friendly garage to clean DPF with a solvent made by Tunap. This made a big difference and it was pretty well cogged up - maybe because of over fuelling and no regens. The Tunap clean involved removal introduction of solvent and then refit plus good blast out. This may help others if they want to try a process that cost <£220 inc VAT.
I shall post an update soon.
Mat
Incidentally, I got a friendly garage to clean DPF with a solvent made by Tunap. This made a big difference and it was pretty well cogged up - maybe because of over fuelling and no regens. The Tunap clean involved removal introduction of solvent and then refit plus good blast out. This may help others if they want to try a process that cost <£220 inc VAT.
I shall post an update soon.
Mat
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S203
Thank you I think it may be resolved. A new thermostat (orig MB is best and was great VFM), so far economy back over 40MPG and seems to run smoother. Gets up to temperature much quicker - well just how it used do. I thought low temp was due to very cold winter.
Thank you all.
M
Thank you all.
M
Thread Starter
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S203
Thank you I think it may be resolved. A new thermostat (orig MB is best and was great VFM), so far economy back over 40MPG and seems to run smoother. Gets up to temperature much quicker - well just how it used do. I thought low temp was due to very cold winter.
Thank you all.
M
Thank you all.
M
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84 300d 2009 e320 bluetec (retired)/, now 2012 E350 4-matic blueefficiency automatic
Thank you I think it may be resolved. A new thermostat (orig MB is best and was great VFM), so far economy back over 40MPG and seems to run smoother. Gets up to temperature much quicker - well just how it used do. I thought low temp was due to very cold winter.
Thank you all.
M
Thank you all.
M
What was the dashboard reading of coolant temperature ?
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S203
Temp reading
Hello again, it was below half way but I thought that was mainly due to extremely cold weather this year. It now reads just above half way all the time - climbing only marginally when towing caravan in recent heat. I have not had further fault messages so I hope it is sorted. How such a simple thing can cause such trouble.... Off for a service this week to a trusted garage, maybe an update to follow. Mat
Senior Member
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84 300d 2009 e320 bluetec (retired)/, now 2012 E350 4-matic blueefficiency automatic
Hello again, it was below half way but I thought that was mainly due to extremely cold weather this year. It now reads just above half way all the time - climbing only marginally when towing caravan in recent heat. I have not had further fault messages so I hope it is sorted. How such a simple thing can cause such trouble.... Off for a service this week to a trusted garage, maybe an update to follow. Mat
How much was the thermostat and the part number?
Mine is normally between 80C/176F to 88C/190F with an outside temp of 20C/68F to 30C/86F. If the outside temp is really hot > 42C/108F, the coolant is slightly above 95C/203F. Hotest was 99C or 210F with outside temp of 46C/115F, AC on and in traffic. AC was not working very well, unless constantly moving.
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From: Jacksonville, FL
2010 C300 (6 Speed)
I'm not too familiar with the Merc diesels, but I know on my old Ford I had to flog it occasionally. If I only did gentle drives the VGT vanes would stick and the EGR would get built up with gunk. Getting the temps higher by flogging it would keep the VGT vanes moving freely and keep the gunk cleaned out.
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S203
I cannot recall part number or price but it was genuine MB (my garage is a good one). Interestingly, my garage says MB dealer had plenty of these thermostats in stock so clearly a common issue. It was very reasonable - about £35 comes to mind as it comes in its own housing which is a bit odd. temp used to slowly climb to appx 1/3 on gauge before change (I thought cold weather was cause) but is now quickly (1 or 2 miles) up to just over half way (no digital reading). I hope this helps. Mat
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223.168 & 213.012 & 906.633 & 214.005
Many of the older CDIs have a second thermostat that also tends to fail. This is for the fuel cooling system.
PS. not sure which car we are talking about, this is a W204 forum but from the signatures I find W203 mentioned.
PS. not sure which car we are talking about, this is a W204 forum but from the signatures I find W203 mentioned.
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84 300d 2009 e320 bluetec (retired)/, now 2012 E350 4-matic blueefficiency automatic
My switch failed at 60,000 miles/5 years. The brake light behaved normal. Was detected with a STAR diagnosis tool (5 minutes). Takes under 20 minutes to change.
