[Brian_C]

I've noticed a recent drop in MPG on my E91 330D, I have it in my head it's down to the DPF, although I have no errors on the dash, mileage is 128k miles with original DPF, on the motorway I notice very varying MPG according to the needle (I'm very conscious of throttle position versus needle position, road gradient etc.) I've had the car mapped about 3 months ago and the mapper noted there was some back pressure present in the dpf. Since I've given it at least 10 good 20-30 mile runs at 2500-3000rpm. I monitored temperatures on a run today cruising in 6th @ 60-70mph I have temperatures of 94°C when I dropped it to 4th to achieve 2500rpm, the temps dropped to 89°C and stayed there. I'm waiting on my inpa/dis software and lead and will try forced regenerating. Currently it feels like the car is trying to regenerate on every journey??

Any advise would be appreciated. Also I plan to remove swirl flaps and egr delete in the coming months, I may just remove dpf completely but if the expense can be spared it would be better.

Brian.

[Rich_D]

The recent drop in mpg will be down the the climate getting colder, you will always see a slight decrease over winter.,

When you get the cable & software, you can actually do a DPF test, over various rev ranges and it will show you if you have a problem, you can also check when it last did a regen, etc, you need DIS for this

[Brian_C]

The temperature where I'm located hasn't changed much in the last 3 months, today was raining but still 14°C, and the drop is approx 5mpg on motorway trip which seems bit extreme for change of maybe 4-5°C in weather, hopefully cable arrives Tuesday or Wednesday so I can check the condition of DPF, thanks for quick reply

[Rich_D]

5mpg is a big drop actually, it's usually 2-3mpg over winter, you need to get DIS running and see what it tells you

[Brian_C]

Ye that looks like the only definite answer to the problem, I'll report back once I get it up and running for anyone with similar problems in the future

[Aragorn30d]

As the DPF ages, ash builds up inside, which is unregeneratable.

Eventually the ash levels become sufficient that the DPF requires replacement. This seems to happen around 140k on average on these cars from what i've read on here.

I guess as you approach the end of life, regens will happen more and more often as the headroom between freshly regenerated and full gets smaller and smaller due to the ash buildup.

[bishbosh]

+1 The ash builds up over time .

My DPF lasted until 145k miles and at that point after a regen it didn't take long for fault code 480a to appear saying it was blocked. The DDE had had a permanent fault for a while: 452a - limited DPF life remaining.

Bought a new DPF as half the usual price, reset the adaptations, cleared the fault codes and it's been fine ever since.

[toonpirate]

I had the exact same issue last week after my mpg suddenly dropped. I first checked my egr thermostat temp and as this wasn't working I changed both egr and main stats.

There was no improvement and so a diagnostics with a cheap code reader showed some error codes relating to DPF. I then went to BMW for a further diagnostic check. I was told my DPF was full even though no warning lights were on the dash and a replacement was recommended at £1500.

I decided to get a second opinion at a BMW specialist and following their diagnostic they stated the differential pressure switch from the DPF was the likely suspect. They have changed loads apparently.

£134 later and the car is back to normal, no new DPF required. My car has 95k on it so I imagine it will need doing at some point. I'll either get it cleaned or look at getting one from Germany like someone on here managed to do.

Fingers crossed.

[toonpirate]

Originally Posted by bishbosh

+1 The ash builds up over time .

My DPF lasted until 145k miles and at that point after a regen it didn't take long for fault code 480a to appear saying it was blocked. The DDE had had a permanent fault for a while: 452a - limited DPF life remaining.

Bought a new DPF as half the usual price, reset the adaptations, cleared the fault codes and it's been fine ever since.

Did you get an original DPF from Germany? If so how do you order one? Thanks.

[bishbosh]

Got it on ebay for £700 from a German seller. It was a genuine one - not a pattern part.

[toonpirate]

Ideal I ll take a look at getting one in Germany. Thanks for that

[Brian_C]

Thanks for all the useful comments guys, small update today my cable and software came so straight to DIS to check condition of dpf, back pressure seemed not too bad, 7 at idle and approx 60 at 2500rpm, requested regeneration and went for a 30 mile drive at 2500rpm, regeneration never started. Scanned for errors when I came and found 4 of the 6 cylinders had glow plug error faults and the most recent was exact mileage I forced regen, so I've ordered 6 new plugs and swirl flaps blanks (while I'm there may as well do them) and will repost back once I get the car regenerating

I know with the mileage being nearly 130k the dpf has probably max 20k left, but these need replacing anyway so will hopefully keep me going until next year

[Calluhan]

Originally Posted by Brian_C

Thanks for all the useful comments guys, small update today my cable and software came so straight to DIS to check condition of dpf, back pressure seemed not too bad, 7 at idle and approx 60 at 2500rpm, requested regeneration and went for a 30 mile drive at 2500rpm, regeneration never started. Scanned for errors when I came and found 4 of the 6 cylinders had glow plug error faults and the most recent was exact mileage I forced regen, so I've ordered 6 new plugs and swirl flaps blanks (while I'm there may as well do them) and will repost back once I get the car regenerating

I know with the mileage being nearly 130k the dpf has probably max 20k left, but these need replacing anyway so will hopefully keep me going until next year

Brian I strongly recommend that you also replace the glow plug controller. Please see my thread here:

http://www.e90post.com/forums/showth...light=calluhan

[marklemac]

Brian, just sharing my info for you, I've done 125k and the Carly app shows I'm at 41g ash mass. I get a regen regular as clockwork, every 584km according to Carly.

I did replace my stats/plugs/controller about 20k ago. Carly says I have 90k left in the dpf.

I do spend a huge amount of time on the motorway/a roads so always getting the car up to temps.

[Brian_C]

Originally Posted by Calluhan

Brian I strongly recommend that you also replace the glow plug controller. Please see my thread here:

http://www.e90post.com/forums/showth...light=calluhan

yes I had budgeted to change the controller also but thought since it was all 6 showing an error it might not be it, but it was only 3 cylinders in your case, the plugs will be here Thursday so I'll do them Thursday and check but I suspect I'll be ordering a controller too, thanks for the heads up

[Brian_C]

Originally Posted by marklemac

Brian, just sharing my info for you, I've done 125k and the Carly app shows I'm at 41g ash mass. I get a regen regular as clockwork, every 584km according to Carly.

I did replace my stats/plugs/controller about 20k ago. Carly says I have 90k left in the dpf.

I do spend a huge amount of time on the motorway/a roads so always getting the car up to temps.

My errors have been appearing since approx 100k so no regen since then, I'm hoping the dpf is in good condition once it's gets a good regen, no lights on the dash gives me some hope that I'll get another 20k+ out of it

[Aragorn30d]

Mine regenned just fine with glowplug faults, so its unlikely yours has done 28k with no regens.

[Brian_C]

Originally Posted by Aragorn30d

Mine regenned just fine with glowplug faults, so its unlikely yours has done 28k with no regens.

I've read numerous threads saying even one glow plug fault will prevent a regeneration? Obviously that's incorrect if yours did perform regens with the error, is there cutoff mileage point then or? Since mine definitely isn't performing one now and everything else is OK, 10 litres fuel, above 88°C, low enough back pressure in dpf etc.