As some will know iv got the 2.0tdi 170pd with the sodding DPF that will be coming off soon, as soon as i stop spending money on other pointless crap.

Anyways i know what a regeneration cycle is and what its for but just dont understand what happens, is it just a case of dumping aload of fuel into the combustion chamber, heating up the exhaust fumes and clearing out the DPF? I ask because my car does alot of town driving now, whereas before it hardly went into town. I notice it doing a regen at least once a day, revs settle at about 1000rpm, the acceleration feels uneven and oh my days does it drink a load of fuel!

Does it seriously need to doing this once a day? it only does about 15-20 or urban driving!

I actually burn more fuel doing this regen (or it seems like it) then the fuel i use all day for work

You have it about covered,

it overfuels to bump up combustion temps to warm the exhaust gasses up enough so it warms the dpf up so it can burn all soot out of it,

I don't really see the point of it really, the older euro 3 engines had none of this crap on and did lots more to gallon, i don't see how burning more fuel can make a car more efficient, done a few forced regens at work and you dont stand behind car while its doing it because the exhaust gasses that come out exhaust are really not nice,

Not sure about VAG group cars but volvos usually do a regen about every 400 miles depending on where and how car is been driven

DPFs have nothing to do with efficiency -their regeneration cycles reduce it and increase CO2 emissions. What they do do is stop all the black smoke that normally comes out the back of a diesel which is harmful. I have always worked in central London and it's really a marked change from 15 to 20 years ago how much pollution from vehicle emissions has reduced, the buildings are a lot cleaner ie not so black anymore and the air is a lot easier to breath.

Unfortunately DPFs are a bit of a poor compromise but will soon be compulsory on all lorries entering London -they will have to be retrofitted to older vehicles at the owners expense. Hopefully in years to come the technology will improve but more and more regulations will come in to place -such as the need for NOX scrubbers and the likes which will most likely increase cost and lower economy further.

Currently the world is obsessed with 'carbon' emissions but that's not even the half of it. I do care about the environment but I'm a realist and am not about to go and live in a mud hut in the woods. I could go on a major rant about all daft 50k Hybrids driving around which are not really 'green' at all but cynically marketed so that rich folks can avoid paying the congestion charge.

They may not have anything to do with the the cars efficiency or economy on the face of things but if i logged down everytime it went into regen mode and over the past 4 month iv had to do a force regen nearly once a week there is more fuel burnt there is just 'eco friendly' i dont get it, kinding shooting themself in the foot.

Its a complete and utter scan to be perfectly honest and i dont know why so many people/companys/manufacturers think its a good idea. A car produces harmful toxins if folk like it or not, putting a DPF just 'covers' it up, in a sence its me saying i lead really healthy life but one day a week i eat chocolate, pizza, binge drink and smoke, if you see what i mean.

Either way mine is coming out, i will keep the DPF just incase i need it in future but in the meantime ill be happy to get rid

I read up somewhere saying that the Vag Group engines usually do a regen between 250-600 miles, regardless of soot buildup. Obviously, if the soot level gets over 45% it will force a regen.

Thankfully, I do a lot of motorway driving (mostly at 70mph) and it gets the exhaust temperatures up naturally, allowing passive regeneration to occur.

The thing that ****es me off, is that a DPF, eventually, will always need replacing. VAG recommend checking them around 120,000 miles (which is the same time as my cambelt) to see how full they are, and if you need a new one. I can't see any garage turning round and saying 'no, you're fine sir', can you?

Edited 6 May, 201214 yr by xreyuk

And they aint cheap either! Plus warranty dont cover them.

I can see the idea behind it all but on the face of it, its just a costly time waster

Hi Ema_Jane,

if your car is doing too many regens, your pressure sensor might be knackered.

Had this on mine (PD 170) and it turned out that the pressure sensor was faulty.

At first no fault codes turned up, but a regen cycle shortly after a cold start, waiting for a red light,

is not the right time (after approx 1km with a cold engine).

As so many things in engine development caused by laws, it is two steps forward (less soot and less micro dust)

and one back. Same years ago when the petrol engines had to have catalysts. Anything blocking the exhaust results

in less efficiency.

you would be better off with a petrol vrs if you are only going to do that sort of mileage now.I think you will have nothing but problems if you plan to use her on short runs.diesel cars now seem to have a big chance of problems when they just do short runs.

you would be better off with a petrol vrs if you are only going to do that sort of mileage now.I think you will have nothing but problems if you plan to use her on short runs.diesel cars now seem to have a big chance of problems when they just do short runs.

Bit late to say that now! Yeah i know that a petrol would apparently be better but id be surprised if they would achieve 41mpg, as for long term problems just keep up to date with oil changes and expect more wear and tear

point taken sorry only trying to help as I do think short runs make a modern diesel suffer in the long term

I learnt quite a bit here:

http://en.wikipedia.org/wiki/Diesel_particulate_filter

Modern diesels are alot more efficient at how they burn the diesel than older diesels ever were, diesel technology in the last 10 to 15 years, well since i started as a mechanic has jumped on leaps and bounds.

Common rail direct injection diesel engines are the norm now and newer laws even mean they have piezo electronic injectors (Google it), they have moved on so far even petrol engines are getting similar technology to make them more efficient.

Catalysers on petrol engines unlike dpf's on diesels usually or should last the life of the car and never have to be changed. I just think there must be a better system or technology than a dpf filter in a exhaust to catch the sut on the way out and then burn it off ever few hundred miles

Try a new fuel filter. Stupid as it sounds, but that has solved all my regen issues I said about in my thread. I'm getting 52mpg daily now on a 9 mile commute (both stop/start traffic and dual carriageway). Before i changed the filter i was lucky to see 47mpg on that journey.

Ema had u ever ur exhaust pressure sensor changed for the new type one? I had similer symtoms when my sensor was shot.

Now it only does a regen very rarely or not at all

Edited 6 May, 201214 yr by Davidsr20

point taken sorry only trying to help as I do think short runs make a modern diesel suffer in the long term

was not having a go! im not that mean

iv always been a diesel fan, for some reason petrol would be a last resort

point taken sorry only trying to help as I do think short runs make a modern diesel suffer in the long term

was not having a go! im not that mean

iv always been a diesel fan, for some reason petrol would be a last resort

http://www.myturbodiesel.com/1000q/vw-jetta-tdi-golf-dpf-filter.htm

was not having a go! im not that mean

iv always been a diesel fan, for some reason petrol would be a last resort

So you would have a Hybrid or Electric before petrol

and a 57 plate Golf TDI 170 having it cut out as it was comprehensively blocked and would not even start

So you would have a Hybrid or Electric before petrol

Not sure I should say this at all, nevermind on a public forum but I would have a Vauxhall Ampera (or Chevrolet Volt).

Runs on its battery until it's flat then the engine takes over to get you to work and re-charges the battery ready for the journey home...

Edited 6 May, 201214 yr by silver1011

Well I love the looks of the vauxhall, now if they could make it as fast as my petrol, I would have one in a heartbeat , reminds me of a Renault Avantime, that too looked futuristic back then, and now

Not sure I should say this at all, nevermind on a public forum but I would have a Vauxhall Ampera (or Chevrolet Volt).

Runs on its battery until it's flat then the engine takes over to get you to work and re-charges the battery ready for the journey home...

Why???

Recently was a article in the USA that only 35% of the already owners of Hybrid cars will by Hybrid again.

Wonder why???

Here in Portugal they are hardly seen, cheaper to buy cars with small diesel engines, like my 1.6tdi Octavia , then the called HYBRIDS have more MPG in real life and on trade in they are worth rubbish.

An example.

Toyota Prius costs over 28000€, I paid 25000€ for my Octavia Break.

Edited 6 May, 201214 yr by alberg

If the Americans had corners , and paid £1.48 a litre, or £6.71 a uk gallon, they would think again

Why???

They are unlikely to be seen here in the UK much either - at over £30,000 its a brave buyer to part with that much cash when as you rightly point out a good few modern diesel engines can achieve better MPG.

I just like the idea of running on pure battery power, all-be-it for a limited distance. It's a safer way of being a fuel gauge gambler (ref. BBC Top Gear) as the petrol engine will always get you home.

Oh and it looks pretty neat unlike the Prius and hasn't yet attracted the stigma currently attributed to Prius drivers...

I can't believe that this thread has gone on so long with no mention of Dr Who...

Seriously, I know you were thinking about buying a second car EJ -a guy at work bought a Fiat Seicento just for getting to and from work he has a people carrier for the family - it's very economical, cheap to run and insure and I don't think that there's anything on it to go wrong - I followed him home once in my Volvo once and I was very impressed at how nippy he was considering I had over 100bhp on him you could probably pick up a reasonable one for £800

Edited 6 May, 201214 yr by greenstripe

And they aint cheap either! Plus warranty dont cover them.

WarrantyWise cover mine on my 170PD Audi. WarrantyDirect on the other hand didn't even know what a DPF was!