DPF Function and Problems

The DPF function is to collect soot particles emitted in the exhaust gases. At a predetermined level the DPF supposedly ‘cleans’ itself by a DPF regeneration, a process that increases the temperature with the DPF and burns off the soot particles.

In theory the vehicle should be able to carry out its regeneration process un- aided under normal driving conditions. However in practice the majority of owners find this isn’t the case and will be told by their main dealer that their driving style is not sufficient for the process to function and that the car needs to then be driven a certain way to clear the DPF. VW group documentation says that ‘short’ or ‘stop/start’ journeys aren’t sufficient and the regeneration process may not complete. We know of customers that have been advised by the VW Group that they do ‘too many motorway miles’ for the regeneration to function correctly. VW Group documentation states:

‘Driving conditions in inner-city and any UK Island do not provide optimum conditions for the regeneration procedure’

‘Consider your driving style and length of journey to allow for the driving conditions required for DPF regeneration’ refer to owners handbook.

In a lot of scenarios the regeneration procedure doesn’t complete and allows the DPF to further block and require forced regeneration or DPF failure and replacement; something that’s not usually covered under warranty.

Performance software and DPF

Problems occur when the cars run performance software for the same reasons they occur in standard vehicles, however depending on the driving style these problems can be accen****ed when using performance software.

The DPF can block or get too hot causing hesitation and poor fuel economy. Although Revo haven’t had any dealers or customers experience it, there have been reports in the press of dry DPF systems actually catching fire. Issues experienced are typically erratic power delivery and fluc****ing fuel economy. The limitations of the factory systems on these engines has led to very high levels of support required for dealers and customers experiencing non-revo related issues with these cars.

"VW group documentation says that ‘short’ or ‘stop/start’ journeys aren’t sufficient and the regeneration process may not complete. We know of customers that have been advised by the VW Group that they do ‘too many motorway miles’ for the regeneration to function correctly."

Sounds like just driving the car in the first place is bad for the DPF.

Too many motorway miles? Is this because driving on the motorways in the UK is too stop start? I thought motorway driving was good for the DPF??

I think the issue with motorway driving can be that 60mph in 6th means low RPM and lots of cold air passing over the exposed DPF on PD engines.

I know its not Skoda but my friends Lexus is220d has had the filter changed 4 times now and Lexus have now stopped using diesel engines because they cant get the system to work properly.

there is the offical Skoda DPF leaflet - believe that if you want - love the bit where it says drive above 23mph and make sure the revs are above 700rpm.

Should never have a problem then gov !

Skoda_DPF_Leaflet_v7.pdf

What I find odd with all this is that the DPF is suposed to clean the exhaust gases so the the gas coming out the end of the tail-pipe is 'clean'. When the DPF 'regenerates' (I wonder if after the 3rd regeneration it likes jelly babies) it burns all the cr@p into the atmosphere in one go.

Seems like a pointless exercise to me.

Good point. Has anyone when they reached the 3rd stage, taken their car into their dealer and witnessed what is actually done in a forced generation? Maybe the dealer captures the exhaust gases carefully in a fancy receptacle? More likely, they use plenty of your fuel, while revving the cr@p out of the car as it emits all of those carefully stored nasties back out into the atmosphere.

What I find odd with all this is that the DPF is suposed to clean the exhaust gases so the the gas coming out the end of the tail-pipe is 'clean'. When the DPF 'regenerates' (I wonder if after the 3rd regeneration it likes jelly babies) it burns all the cr@p into the atmosphere in one go.

Seems like a pointless exercise to me.

The difference is that it's not emitted as soot with the intention that the burnt matter that's expelled by the DPF isn't as bad.

However in practice the majority of owners find this isn’t the case and will be told by their main dealer that their driving style is not sufficient for the process to function and that the car needs to then be driven a certain way to clear the DPF

What is the source for this post? There are a fair few DPF problems on this forum but then there's a lot of problems reported on this forum in general which is what I'd expect as people are more likely to report problems than good experiences on a forum. I find it hard to believe that the majority have problems with DPF because if it wasn't for this forum I wouldn't know about DPF problems, I haven't had any on my own car and no friends with diesels have reported issues either. I'm not saying DPF problems don't exist but don't believe that most people have trouble with them. Also the 'too many motorway miles' doesn't make any sense either.

John

There is a solution if you have a troublesome DPF - remove it.

I know someone that has just removed it from a Golf 170 tdi, the gains are great it was a little expensive but cheaper than a new DPF.

He said it feels quicker, sounds deeper?, and better MPG the next task is a map.

The whole DPF thing is a classic case of under developed technology foisted on the public. Guess who the guinea pigs are? I didn't buy a diesel this time because I knew of the issues. I got an Octy 1.8Tsi instead, and I'm a real diesel enthusiast. I often speak to people in the motor trade and I was recently speaking to a BMW salesman on the Isle of Wight. That particular franchise is also the Seat franchise on the IOW. Salesman tells me that they REFUSE to sell anyone a Seat diesel, because of DPF problems.

As we all know, Seat are also VAG, using the same engines and systems etc. Salesman tells me that VAG DPF systems are regarded as troublesome in the trade. So are Fiat apparently.

I think the obvious solution is to get the thing removed as many people are doing. It's not at this point in time an MOT issue apparently. The other development on the DPF front is that users are discovering that it is perfectly possible to clean out your DPF using solvents and power wash. In other words, just jet the gunge out. Have a Google search - there's quite a lot about this online.

Has anyone thought about wrapping a DPF and the pipework up to it in exhaust wrap to keep the heat in?

Derp,

As I have posted before on multiple occassions, we bought a 1.6CR TDI in Sept 2010, in the 30,000 miles since (and the car was off the road for 3 months) despite repeated 3 mile and stop journeys to & from my work, interspersed with longer runs at the week-end.

I HAVE NEVER BEEN AWARE THAT THERE WAS A DPF FITTED.

well I tell a lie as i did smell it burning off in the early days.

BUT no warning lights....................ever.

Which is to say as I postulated when we bought the car,

I have every reason to belive that VW engineering in respect of a designed from scratch DPF installation WILL WORK.

The PD engine DPF installation was basically a less than ideally positioned "best bit" retro fit "bodge"

And the !"£$%^& of a loaner Vauxhall gave endless DPF troubles in the short while we had it, took a tremendous amount of revs and distance to clear.......this on top of the already appalling fuel consumption for a diesel

Again

All hail the VW group.

Cheers

Marcus

PS

The 1.6TDI installation is snugly wrapped up in at the rear of the engine below the windscreen............right next the turbo and ..............................................hot, hot hot.

i.e.

Properly designed, not mid life retro-fit

PPS

With the DSG gearbox and my gentle driving style the engine revs are rarely much above 1500, only "blipping" just short of 2000 before changing up

Edited 3 July, 201213 yr by dieseldogg

Okay first off, folk from the Isle of wight have a lot more to worry about than the the fuel they use. First recommendation is to move to a larger gene pool

Second, the only reason for fitting a DPF is to stop the car from belching soot. Peugeot used a different system that also has loads of problems. So do other manufacturers. The only cause of soot from a diesel is unburned fuel, getting a remap will tend to make this happen more.

You just need to let the car rev enough when its hot. Warm it up then drive it hard.

Or not and see my post above TDIum's

srsly!

Anyway I presume that if the engine needed higher engine revs to burn off the DPF the VW boffinins would have set up the DSG gearbox alogrythm(s) to hold the gears longer/run at higher revs, if so instructed by the DPF managment electronics.

Simples!

But it dont!

Cos it dont need to.

PS

Anyway I tought that the only reason for the IoW music festival was to introduce genetic diversity to the otherwise limited local gene-pool

Edited 3 July, 201213 yr by dieseldogg

Okay first off, folk from the Isle of wight have a lot more to worry about than the the fuel they use. First recommendation is to move to a larger gene pool

LMAO!! Seriously I've just spat tea all over the place!

Second, the only reason for fitting a DPF is to stop the car from belching soot. Peugeot used a different system that also has loads of problems. So do other manufacturers. The only cause of soot from a diesel is unburned fuel, getting a remap will tend to make this happen more.

You just need to let the car rev enough when its hot. Warm it up then drive it hard.

Kinda defeats the object of a diesel for economy reasons!

This whole DPF issue is cobblers and yet another example of Brussles foisting things on us. Rant Rant

Erm,

Despite being a 53 year old curmundgeon I kinda think DPF's are a good idea, having seen what I used to habitually wipe off the inside of the car windscreen.

I dont think all that particulate matter could be good for the lungs?

After all they used to think putting lead in the petrol was a good idea??

And sending weans with a bad chest to sniff the fresh Tar, them phenols will do you a power of good! Man Sur!

PS

From someone who laughed at Cresote, splash it on all over of a summers day when wearing shorts and little else 35 year ago.

I is now quite sensitive to Cresote, even a whiff!

Ditto a time served Joiner to hardwood dust, particularly peppery Iroko?

Ditto a now dead painter, that I knew, to some paint products.

Cheers

M

Lets get this straight - there clearly needs to be a system to filter out diesel particulates, but the current system is quite utterly insane and could only have been dreamt up by daft twerps in Brussels, who decided to use a system whereby the engine computer sends unburnt fuel down the exhaust pipe with the intention of starting a bonfire in the exhaust system?

Were they completely off their trolleys? Tell this to the owners of 'S' Type Jags that caught fire because of the DPF's. Tell it to the owners of Mazda 6's, when their engines literally blew up, because of diesel runaway caused by excess fuel getting in the sump. Tell it to the owners of Fiat Doblo's. Do you know anyone with a diesel Fiat Doblo that actually runs properly? I could go on.....

What is needed to solve the particulate problem with diesels, is a simple five quid filter that you screw on the end of the exhaust pipe. When it gets full up with soot and the engine won't run properly, you buy a new one, unscrew the old one and put one the new one.

Has the whole world gone completely mad? I'm off up the pub in an hour with my mate, Salvatores sells a good pint that solves most problems.

Anyway I presume that if the engine needed higher engine revs to burn off the DPF the VW boffinins would have set up the DSG gearbox alogrythm(s) to hold the gears longer/run at higher revs, if so instructed by the DPF managment electronics.

Simples!

But it dont!

Cos it dont need to.

I've read on here that DSG equipped cars do just that. During a DPF regen the gearbox holds gears for slightly longer to maintain a higher RPM to help the regen complete.

Before my vRS i had a E90 330d with a DPF. I never knew it had a DPF, never felt regens (if the car even did them??) it was mapped up to the eyeballs and ran faultlessly the whole time i owned it.

Perhaps VAG should take a leaf out of BMW's tech book on how to make a DPF system that works.

Hello mr......... Heres your new vw with dpf, if you dont drive it it will be just fine.