DPF Re-Gen

[A3Kent]

I've read various threads on here saying that the DPF will only re-generate at a certain speed so most of the time on motorways etc.

Yesterday I had a strong fume smell enter the cockpit of the car (2009 2.0TDI 170) on 3 occasions during seperate less than 3 mile journeys so was only doing 40mph tops. I was a bit concerned.

The car was already booked into an Audi Dealership today to have some other work done so I mentioned the smell and they said it was probably the re-generation process of the DPF. I said to them that I thought it only happened at higher speeds but he said that it can happen at any time. This is an Audi Dealer so you'd hope you were getting the correct info!

Who's got some definitive answers on this subject or do I assume that Audi actually know what they are talking about?

Cheers

 

[Geraldy212]

A DPF regeration is a process of burning off the particulates inside the filter. That requires considerable heat, hence the common suggestion to take the car for a spin at higher speeds, and that should be sufficient. The auto-regen process may start (in panic because the filter is nearly clogged), and if one drives at slower speeds, that burning process may take longer, and/or may not be completed. I suggest this may be causing the smell you have experienced. Best thing to do is in fact go for a spirited drive, and see if this does the job. Not a perfect system since it relies on the driver heating up the exhaust when needed, over which Audi has absolutely no control. Hope this helps a bit.

 

[Sidhu88]

I've read various threads on here saying that the DPF will only re-generate at a certain speed so most of the time on motorways etc.

Yesterday I had a strong fume smell enter the cockpit of the car (2009 2.0TDI 170) on 3 occasions during seperate less than 3 mile journeys so was only doing 40mph tops. I was a bit concerned.

The car was already booked into an Audi Dealership today to have some other work done so I mentioned the smell and they said it was probably the re-generation process of the DPF. I said to them that I thought it only happened at higher speeds but he said that it can happen at any time. This is an Audi Dealer so you'd hope you were getting the correct info!

Who's got some definitive answers on this subject or do I assume that Audi actually know what they are talking about?

Cheers

Next time u do a cold start, do it with the bonnet open, and look for any smoke coming from the back of the engine where the turbo is. I had problems with my EGR which i eventually blocked off, i had similar problems, quite a toxic smell coming in to the cabin which was more apparent at idle. Since then, i've had no problems. I wouldn't listen to what audi say, the last time i took it in he said my DPF was blocked, did a check to see how blocked it was, returned a value of 9%. If the problem persists, buy an EGR blank off ebay, pop it in and see how u get on.

 

[A3Kent]

Hi Sidhu88. Interesting you mention the EGR.

About one month ago I had the emission control light come on, on the dash. With it being under warranty, I took it back to Audi and they said it was the EGR coolant pump, which they replaced. All seemed to be fine afterwards until now and I thought it could be related and even mentioned it to the dealer that its with now this morning (different to the dealer that did the EGR pump) but he said it was just a small water pump so it wouldn't be that.

It's obviously related to the EGR then? Is this in-turn related to the DPF? Sorry if this sounds like a stupid question, i'm just trying to figure out if Audi actually know what they are doing or jsut trying to fob me off with some other rubbish.

Thanks

 

[nally]

Mine dose the same as said go for a good run on it and start driving it a bit harder ( don't change gear so eirly )

 

[A3Kent]

Thanks nally - So you get the fume/toxic smell at low speed? Your car is almost identical to mine so I feel happier.

I'd like to think I drove it pretty hard but obviously not hard enough and I do tend to shift through the manual gearbox pretty quickly. When I get it back, hopefully tomorrow, i'm going to thrash the living day lights out of her!

 

[Sidhu88]

Hi Sidhu88. Interesting you mention the EGR.

About one month ago I had the emission control light come on, on the dash. With it being under warranty, I took it back to Audi and they said it was the EGR coolant pump, which they replaced. All seemed to be fine afterwards until now and I thought it could be related and even mentioned it to the dealer that its with now this morning (different to the dealer that did the EGR pump) but he said it was just a small water pump so it wouldn't be that.

It's obviously related to the EGR then? Is this in-turn related to the DPF? Sorry if this sounds like a stupid question, i'm just trying to figure out if Audi actually know what they are doing or jsut trying to fob me off with some other rubbish.

Thanks

I've been fobbed off from day 1 with em, they did the recall on the injectors on mine and it all went downhill from there.
I don't think you'll have any problems with your DPF, unless they can physically show you something then I wouldn't believe it. They'll probably say you have to pay for diagnostics before they even look at it but because I kicked up a fuss last time I went and had a rant on here (which they saw) they don't want me going back to them so they did the diagnostics on the spot just so I'd leave pretty much straight away. As mentioned the guy checked the DPF blockage levels and it read 9%, before that he said I had DPF problems.

From what I've read, when the EGR is dismantled, if its cleaned with the wrong type of fluid it can be damaged. If its not correctly replaced then people have had issues with the anti shudder valve. I'm assuming they would have disconnected it all during the process so could well be.

As for it being related to the DPF, apparently so. From what i've been told/understand, a dodgy EGR will increase soot levels to the DPF, which would then block up the DPF quicker, so if your doing alot of economical town driving it'll block up fairly quick. I would probably have this problem with mine since i've blocked my EGR off completely, but i'm heavy footed and do a 20 odd mile drive a few times a week which is mainly on the m4 so it probably gets upto temperature to burn off the soot quite easily. It may be worth taking it to an independant specialist if you've got the money to do it, I'd be more inclined to trust there opinion over Audi.

P.s. mines a 56 2.0 TDI 170.

 

[A3Kent]

Haha! love the fact they had a look on here! Maybe they'll notice my Audi-Sport.net sticker in the window and think twice about trying to avoid what the possible real issue is. As it's under warranty i'll be taking it back until I don't have a single problem no matter how big or small it is.

I used to take my old Golf and previous A3 to QST in Haywards Heath who i've always found pretty good so maybe i'll run it over to them if I get similar problems.

Appreciate your words.

 

[astradti16v]

You can tell when the car attempts to do a regen, the car will feel very lumpy and the idle rises. It will do a regen once it is at the correct temperature. Mine always does it best in 4th at approx 2,600rpm over approx 8 miles.

 

[a6_chris]

the sticker on my windscreen states optimum revs at 2000 - 2500 rpm and a speed above 50 mph for 30 or so minutes

 

[nally]

Thanks nally - So you get the fume/toxic smell at low speed? Your car is almost identical to mine so I feel happier.

I'd like to think I drove it pretty hard but obviously not hard enough and I do tend to shift through the manual gearbox pretty quickly. When I get it back, hopefully tomorrow, i'm going to thrash the living day lights out of her!

my car had its mot last week and I spoke to my mechanic he was saying to me to drive it in Lower gears at higher speeds as I do about 20 miles a day and its bit getting fully warmed and as its a roads it's 60 mph at the highest I have done it all week and it seems ok and it's not yet happened.

 

[A3Kent]

my car had its mot last week and I spoke to my mechanic he was saying to me to drive it in Lower gears at higher speeds as I do about 20 miles a day and its bit getting fully warmed and as its a roads it's 60 mph at the highest I have done it all week and it seems ok and it's not yet happened.

Funnily enough, I too do about 25miles a day but not on motorways or dual carriage ways so will only hit speeds of 60mph tops. Maybe once or twice every 2 or 3 weeks i'll have a half an hour run on the motorway which i'd hope was enough to keep things in order.

 

[max69vk]

Dont worry about having to do a motorway run to do a regen, just keep the car in a lower gear to keep the engine above 2.5k rpm & it'll do the same job after a few miles. Works for me every time

 

[thebluefox]

Its wonderful, buy a diesel because of its fuel economy and low end pull.

Get told you need to to rag it to make sure everything keeps working.

Genius.

 

[A3Kent]

Right, well i've had no call today to let me know what's going on regarding my original problem which was the replacement of a top suspension mount on the front passenger side. The car would make a loud pinging/knocking noise at slow speeds on full lock so when parking etc. They told me yesterday they were waiting to hear back from Audi UK to see if it's covered under warranty which had already been confirmed to me that it was covered by the first dealer 2 weeks ago (they couldn't do it as they didn't have time!).

I'm not letting this run into a third day as I have no car and i'm now fed up with trying to call them and someone telling me that the service guy will call me back as he's unavailable.

I'm going to pick it up at half 5, regardless of whether they know i'm coming to get it or not.

To be honest, i've had nothing but bad experience with them every time i've used them but thought as this was a quick warranty job, it would be in and out in no time, especially as the problem had already been diagnosed.

 

[nally]

That's the one the car is just getting warm so extra **** is in burnt in the dpf I have just come home with mine idleing rough and looked like steam out the exaust a quick 60mph in 3rd gear don't it the world of good for a few miles

 

[A3Kent]

Well, I've got it back - not fixed. He told me that Audi UK aren't sure if it's a warranty job or not and may have to send someone out to look at it. For the sake of less than £200 on parts that sounds like a complete waste of time and money. He said he was going to call me when he had some more answers. Never mind, it's not going back there, i've had enough of them. I'll take it back to where I bought it who had already told me it would be covered under warranty. Shame they are so far away! Will call them later to book it in.

Regarding the toxic/fume smell, well it hasn't happened since i've had it back although I keep thinking I can smell it but it may be some old banger in front! It certainly hasn't given me the really strong toxic/fume smell I had on Sunday.

Out of interest - My car is a manual and I tend to change gear when the DIS tells me to do so (within reason) cause I think i'm getting good economy that way. Would the DIS notice a problem and start telling you to shift up and down the gearbox a bit later in order to give the car a few more revs? I think I may have noticed it doing it on my way home from Audi yesterday and then on the early part of my journey to work this morning. Or am I talking rubbish?

 

[Sidhu88]

Not sure about the DIS, im guessing uve got an 8p3? I dont have a shift light. I just shift as and when i feel. Audi are a bunch of jokers. God knows who they're hiring to carry out theyre work nowadays.

 

[A3Kent]

Yeah it's an 8P3 with the white DIS. Just wondering if it's clever enough to delay the shift notifications if it thinks the car needs extra revs to help something along.

 

[Sidhu88]

So what year is urs then? I thut some of the newer a3s came with the common rail diesel which shud have been a lot better than the previous PD engines. Have u tried starting the car with the bonnet up yet? See if there are any puffs of smoke around the turbo? The smell i was gettin was a strong burnt diesel fuel smell. Im fairly sure the egr was leaking fumes somewhere and that was being sucked into the ventilation system

 

[Cossie_boy]

You can tell when the car attempts to do a regen, the car will feel very lumpy and the idle rises. It will do a regen once it is at the correct temperature. Mine always does it best in 4th at approx 2,600rpm over approx 8 miles.

This is what ive been looking for! would anyone say 900 is standard and 1000 is when its doing the regen?

 

[A3Kent]

So what year is urs then? I thut some of the newer a3s came with the common rail diesel which shud have been a lot better than the previous PD engines. Have u tried starting the car with the bonnet up yet? See if there are any puffs of smoke around the turbo? The smell i was gettin was a strong burnt diesel fuel smell. Im fairly sure the egr was leaking fumes somewhere and that was being sucked into the ventilation system

Hi mate, sorry it's taken me a while to reply.

Mines a 2009 170 so it's a common rail. I've finally got the suspension mount sorted having gone back to where I bought it and I haven't had any problems, even in the week leading up to the other repair. No sign of that strong fume smell so i'm inclined to think it was a DPF regen causing the smell. I am of course still not 100% convinced as the EGR coolant pump was changed recently and I think it may be related but at the moment, all seems OK touch wood. Obviously if things change I will be back on to report

Appreciate your help with this

 

[astradti16v]

This is what ive been looking for! would anyone say 900 is standard and 1000 is when its doing the regen?

Yeh its something like that. When in neutral the revs some stick at 1050 and then drop to 900 and rise again to 1050.
Had this happen to me again the other day, I had to go into 3rd and tried to keep it at 2,500 rpm and it was fine.

 

[Cossie_boy]

cheers, i wish id know this before, lol

so how bad is yours when its doing the regen? as mine is very hesititant, juddery and stuttery!

 

[The Governor]

Out of interest - My car is a manual and I tend to change gear when the DIS tells me to do so (within reason) cause I think i'm getting good economy that way. Would the DIS notice a problem and start telling you to shift up and down the gearbox a bit later in order to give the car a few more revs? I think I may have noticed it doing it on my way home from Audi yesterday and then on the early part of my journey to work this morning. Or am I talking rubbish?

I have a manual, I'm near certain the DIS isn't that clever. I quite often find the DIS is telling you to change up far too early and would labour the engine, I ignore it primarily because I can drive and I don't need a computer designed by a knob to tell me how to change gear

The DPF is similarly designed by a bell-end, mine usually waits to do a regen when I'm doing a short journey. I compare it with my previous car (3 series) and I never even used to think about the DPF, with the Audi it's a frequent event.

 

[Cossie_boy]

How frequent gov?

My light has come on after 75 miles of motorway ish driving!

 

[The Governor]

I've not had the light yet, my car has only done about 10k. I make note of how often I get an active regen, I've had 4 since getting the car, it had about 2k on the clock then. Initially I had two very close togetehr, within a few hundred miles, the next one was 3k later, the last 2000 or so later.

At least they're the ones I noticed, if I happened to be driving it's more difficult to tell, but when stopped the 1000 rpm is a dead giveaway... silly system if you ask me, I will think hard about a DPF removal once it's out of warranty, depending on how the MOT rules go...

 

[chinnyhill10]

With the DPF regen, does anyone think better quality fuel will create less soot hence enable quicker or less frequent regens?

My previous car was a Golf mk5 140. If I put Tesco diesel in it, the exhaust was sooty and stank. Stick standard Shell or BP in there it was much better. Put V Power or BP Ultimate in and the thing had no smell at all and seemed to be very clean indeed.

So question is, do the expensive premium fuels help the DPF because they create less soot? Or is my theory rubbish?

 

[Vertigo1]

There's a lot of confusion about the "regeneration" cycle of the DPF.

The advice about running the car at certain revs/speed for certain periods now and then is to allow the DPF to clear itself out "automatically", by generating the exhaust pressures and temperatures necessary for this process.

If you don't do this often enough, then the system will go into a "manual" regeneration mode whereby it'll cause the DPF to heat up to initiate the burn-off process so it can clear itself. You'll notice this happening primarily because the engine idle speed will rise to 1000rpm rather than 800rpm. Also, increased noise or harshness may be detectable whilst this is happening. Basically the ECU is running the engine in a "weird" way to generate the exhaust conditions required to force the DPF to regenerate.

 

[RallyX]

Guys, I feel your pain with all the DPF problems you are having. When I had an A4 cab the light came on for the dpf and all I did was to put a brick on the throttle at 2500rpm for 20 mins. Never had the light come on again. Now got an A3 PD170 as a second car and that has come one once in the last 18 months. Did the same as before and never had a light appear again. If it does come on again I will do the same again or go for a complete removal depending on new MOT laws coming in soon.

 

[Brodster]

depending on new MOT laws coming in soon.

If the MOT regs change which I dont think they will.....the DPF will be a visual inspection only. Thats why the original cannister is kept and not a by-pass pipe fitted.......just in case.