E90 DPF woes.
E90 DPF woes.
Author
Discussion

LukeSi

Original Poster:

5,780 posts

192 months

Friday 6th April 2012
quotequote all
The 3er has shown the DPF warning on the dash. However BMW cleaned the DPF out just over 1000 miles ago. The car is driven a short amount of miles however this includes a stretch of 70mph and my father has quite a heavy foot. Is it possible that the DPF has become clogged again or is it a mechanical fault. BMW said last time they had to force the car to perform a regen. Could this be a software or mechanical fault as the 70 road allows optimal regen conditions.

Thanks in advance.

TheEnd

15,370 posts

219 months

Friday 6th April 2012
quotequote all
It could be a car problem if it can't get to the right temp to start a regen.

LukeSi

Original Poster:

5,780 posts

192 months

Friday 6th April 2012
quotequote all
TheEnd said:
It could be a car problem if it can't get to the right temp to start a regen.
Forgot to add it is the 3.0d, possible EGR valve issue?

TheEnd

15,370 posts

219 months

Friday 6th April 2012
quotequote all
Maybe, it's the kind of thing you'll end up cleaning every now and again, but there is a coolant thermostat and an EGR thermostat which, if they have problems, keep the engine temp just below the ideal operating temp, and the regens never start.

I think there might be a way to get the dash to show the actual digital engine temp which is a good starting point as a "cool" engine rarely puts up any other warnings or clues.

LukeSi

Original Poster:

5,780 posts

192 months

Saturday 7th April 2012
quotequote all
Hmm well this is odd. We took it down the motorway a bit, DPF warning didn't come on at first so we thought, good it must have sorted itself. Get onto the motorway, cruising at 70mph, ample time for the engine to have warmed up, basically optimal conditions for a regen and the warning comes on. So now I am thinking either sensors, or as said before possibly the thermostat/egr sensors.

EssexIan

135 posts

314 months

Sunday 8th April 2012
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Sounds to me like BMW just forced a regen, may be wrong but I think the main dealers stance is dpf can't be cleaned and must be replaced, my apologies if I have got this wrong.

Unfortunately what you describe is exactly what I have been through recently, only option in the end was replace or remove dpf, I had mine removed and ecu re-mapped to suit.

As others have suggested I am certain the poor operation of the main and egr thermostats is what finished my dpf off, if the car does not get hot enough then it will not regen no matter what driving conditions it is being used under. Also now you have dpf warning up the car will not try to regen the dpf, you must get warning light reset. BMW or good independent can also carry out a dpf test at the same time, if the back pressure is ok then they can force a regen. They should also be able to check the temperature the car is reaching and tell you if you need to replace thermostats, I think the egr one on it's own will only slow down the rate of warm up, I do't think it will have an overall effect on running temperature.

Not sure where in the country you are, if you are anywhere around Essex PMW ltd in Chelmsford are a good place to start with this, if the dpf is blocked then they should be able to clean it successfuly for you, costing rather less than replace/ remove.

Good Luck
Ian

LukeSi

Original Poster:

5,780 posts

192 months

Monday 9th April 2012
quotequote all
EssexIan said:
Sounds to me like BMW just forced a regen, may be wrong but I think the main dealers stance is dpf can't be cleaned and must be replaced, my apologies if I have got this wrong.

Unfortunately what you describe is exactly what I have been through recently, only option in the end was replace or remove dpf, I had mine removed and ecu re-mapped to suit.

As others have suggested I am certain the poor operation of the main and egr thermostats is what finished my dpf off, if the car does not get hot enough then it will not regen no matter what driving conditions it is being used under. Also now you have dpf warning up the car will not try to regen the dpf, you must get warning light reset. BMW or good independent can also carry out a dpf test at the same time, if the back pressure is ok then they can force a regen. They should also be able to check the temperature the car is reaching and tell you if you need to replace thermostats, I think the egr one on it's own will only slow down the rate of warm up, I do't think it will have an overall effect on running temperature.

Not sure where in the country you are, if you are anywhere around Essex PMW ltd in Chelmsford are a good place to start with this, if the dpf is blocked then they should be able to clean it successfuly for you, costing rather less than replace/ remove.

Good Luck
Ian
Luckily the car is just about still in warranty and is due a service within the next couple of weeks. It does sound like as has been said the thermostats are on the blink. I think I shall request BMW replace these parts and the DPF itself to be on the safe side. I would rather not have a repeat incident once the car is out of warranty because the faulty components are still present. I can quite see them trying to fob us off with the "It just needs a regen" excuse. They tried to do a regen before and put 100 miles on it (obviously took it for 50 miles to try and regen first time, nothing happened, so forced it to regen for the other 50 miles (although to balance that we used all the fuel in their loan car hehe). Might see if we can convince them to lend us an M3 (or to be extra cheeky see if we can borrow their M5 demo (if they have one)) for the day. I'm sure if we ask nicely enough they will.

4rephill

5,171 posts

209 months

Monday 9th April 2012
quotequote all
Modern diesels with DPF's don't just need a "cruise" at70 mph on a motorway to clean out the DPF, they really need an Italian tune up on a regular basis to do the job, plenty of revs through the gears to get the engine hot and to force the re-gen to operate.

Cruising down the motorway at 70mph will bring the car up to temperature but it's too slow to get the Re-gen to operate correctly. At 70mph in 6th you're not pulling any revs.

Every now and again, modern diesels need to be raced along (within the speed limits naturally!), to clean the exhaust system out fully.

This is why modern diesels are not suited to round town driving anymore, they never get hot enough for the re-gen to work and then clog up.


LukeSi

Original Poster:

5,780 posts

192 months

Monday 9th April 2012
quotequote all
4rephill said:
Modern diesels with DPF's don't just need a "cruise" at70 mph on a motorway to clean out the DPF, they really need an Italian tune up on a regular basis to do the job, plenty of revs through the gears to get the engine hot and to force the re-gen to operate.

Cruising down the motorway at 70mph will bring the car up to temperature but it's too slow to get the Re-gen to operate correctly. At 70mph in 6th you're not pulling any revs.

Every now and again, modern diesels need to be raced along (within the speed limits naturally!), to clean the exhaust system out fully.

This is why modern diesels are not suited to round town driving anymore, they never get hot enough for the re-gen to work and then clog up.
Easier said than done in an auto hehe

EssexIan

135 posts

314 months

Monday 9th April 2012
quotequote all
4rephill said:
Modern diesels with DPF's don't just need a "cruise" at70 mph on a motorway to clean out the DPF, they really need an Italian tune up on a regular basis to do the job, plenty of revs through the gears to get the engine hot and to force the re-gen to operate.

Cruising down the motorway at 70mph will bring the car up to temperature but it's too slow to get the Re-gen to operate correctly. At 70mph in 6th you're not pulling any revs.

Every now and again, modern diesels need to be raced along (within the speed limits naturally!), to clean the exhaust system out fully.

This is why modern diesels are not suited to round town driving anymore, they never get hot enough for the re-gen to work and then clog up.
What modern diesels need is for everything to be working properly, if the car gets warm enough it will perform a regen so long as certain parameters are met irrespective of speed!

What makes them less suited to town driving is the fitment of dpf in the first place and the likes of BMW not bothering to fit a temperature gauge so that no one can tell if the car is reaching full operating temperature or not. The only way to do this at the moment is dig around in sub menus within the dash display that most owners probably don't know exist.

roofer

5,136 posts

242 months

Monday 9th April 2012
quotequote all
4rephill said:
Modern diesels with DPF's don't just need a "cruise" at70 mph on a motorway to clean out the DPF, they really need an Italian tune up on a regular basis to do the job, plenty of revs through the gears to get the engine hot and to force the re-gen to operate.

Cruising down the motorway at 70mph will bring the car up to temperature but it's too slow to get the Re-gen to operate correctly. At 70mph in 6th you're not pulling any revs.

Every now and again, modern diesels need to be raced along (within the speed limits naturally!), to clean the exhaust system out fully.

This is why modern diesels are not suited to round town driving anymore, they never get hot enough for the re-gen to work and then clog up.
This. I took my 335d to 130k without ever seeing the light, sold it to a mate who let his missus drive it around town, DPF light came on within a week. You can hear a regen happening, about 120 leptons for 10 minutes cleans them out a treat.

gareth h

4,331 posts

261 months

Tuesday 10th April 2012
quotequote all
I binned the DPF and fitted a pipe and remap from here http://www.ecotune-scotland.co.uk/vehicles/cars
it supposedly takes the 123d to 275hp, can't confirm the numbers but it is very impressive, a little more black smoke but still within mot limits.

StottyZr

6,860 posts

194 months

Tuesday 10th April 2012
quotequote all
gareth h said:
I binned the DPF and fitted a pipe and remap from here http://www.ecotune-scotland.co.uk/vehicles/cars
it supposedly takes the 123d to 275hp, can't confirm the numbers but it is very impressive, a little more black smoke but still within mot limits.
I take it we were on the same recent group buy? Makes a hell of a difference doesn't it biggrin

EssexIan

135 posts

314 months

Tuesday 10th April 2012
quotequote all
gareth h said:
I binned the DPF and fitted a pipe and remap from here http://www.ecotune-scotland.co.uk/vehicles/cars
it supposedly takes the 123d to 275hp, can't confirm the numbers but it is very impressive, a little more black smoke but still within mot limits.
I also have one of Stan's pipes on my 335d, makes for a totally different car! biggrin

Ian

4rephill

5,171 posts

209 months

Tuesday 10th April 2012
quotequote all
EssexIan said:
What modern diesels need is for everything to be working properly, if the car gets warm enough it will perform a regen so long as certain parameters are met irrespective of speed!
Hence the reason I said the car needs revs, not speed! (The clue was in the statement about cruising at 70 mph in top gear not really being suitable to get the re-gen to work correctly and fully).

Try reading this: http://www.theaa.com/motoring_advice/fuels-and-env...

In particular:

"AA experience:
We're seeing some evidence of DPF systems failing to regenerate even on cars used mainly on motorways.

On cars with a very high sixth gear the engine revs may be too low to generate sufficient exhaust temperature for regeneration. Occasional harder driving in lower gears should be sufficient to burn off the soot in such cases."

(I don't make this stuff up as I go along you know!, I do my research and make sure I'm not giving out duff information based on rumour and misinformation! rolleyes )



EssexIan said:
What makes them less suited to town driving is the fitment of dpf in the first place and the likes of BMW not bothering to fit a temperature gauge so that no one can tell if the car is reaching full operating temperature or not. The only way to do this at the moment is dig around in sub menus within the dash display that most owners probably don't know exist.
Without DPF's fitted, modern day diesel engines cannot meet the latest legislation for Diesel emissions and so would not be available for sale for any type of driving.

As for how warm an engine gets, it shouldn't be too hard for an owner to find out how far they need to drive their car to get it suitably warmed up, even if their car is not fitted with temperature gauge. If they can't figure that out (by asking at a dealership or looking on the internet for example), perhaps they shouldn't be driving at all - After all, it's not rocket science at the end of the day!

TheEnd

15,370 posts

219 months

Wednesday 11th April 2012
quotequote all
4rephill said:
As for how warm an engine gets, it shouldn't be too hard for an owner to find out how far they need to drive their car to get it suitably warmed up, even if their car is not fitted with temperature gauge. If they can't figure that out (by asking at a dealership or looking on the internet for example), perhaps they shouldn't be driving at all - After all, it's not rocket science at the end of the day!
The problem is crappy thermostats.
Without a proper gauge, the engine will happily run at 70'c, nice warm air, and no clues that it isn't reaching the 80-90'c that it should be.

There can be up to 3 thermostats on them for the radiator, EGR and autobox, and if one fails, the temp can be brought down enough to stop regenerations, but to not give any other effects.

gareth h

4,331 posts

261 months

Saturday 14th April 2012
quotequote all
StottyZr said:
I take it we were on the same recent group buy? Makes a hell of a difference doesn't it biggrin
Yes night and day, I went with the maxtune but am quite keen to give the ecotune a go and see what difference it makes to economy.