It's a risk yes - but I've yet to hear of a vehicle failing under the new tests where a DPF has been removed...

But give the authorities time, it's a bit risky IMO.

We now have drive by checks for reg/stolen/unpaid fines etc.......tack on tail pipe emissions......what's to stop that....give it time IMO.

It's a risk yes - but I've yet to hear of a vehicle failing under the new tests where a DPF has been removed...

 

To be fair it's only been in operation since February 2014.

 

https://www.gov.uk/government/news/new-rules-for-mot-to-test-for-diesel-particulate-filter

 

Knowing my luck I'd probably end up being the first to fail if I bypassed the DPF.

 

Up here even the police get stopped.

 

http://youtu.be/S-SLLOqp1zo

Muddyboots, does this mean you are no longer planning to stage 2 your car and remove the DPF if you are spending this amount of time looking into the cycles?

 

My 170CR Yeti is now a bit over two years old, with 33,000 miles on it.

In that time I've only actually noticed a regen cycle about three times.

 

I haven't made any decisions yet...

 

I decided I wanted to fully understand the system, and how it's functioning on my particular car on my typical journeys, before deciding what to do.

Much of the publicised fear of DPFs is based around earlier systems and is probably unfounded now, on the VAG CR engines at least. So it was interesting to read the self-study guides on the CR engine and on the newer DPFs to see exactly what has changed.

 

From what I've read and logged, I'm not worried about the DPF clogging. 

 

What has surprised me though, is just how often it's having to do an active regen. I'd assumed that my longer journeys would be sufficient for most of the soot to be got rid of passively, but to find it's actually doing active regens every 200-300 miles, was definitely a surprise.

This will be causing an increase in fuel consumption - but I don't think I can quantify how much by.

I've read anecdotal evidence from a few other CR170 owners who've had it done, that they have seen significant improvements in economy. Knowing now that I'm getting active regens so frequently makes me think I could benefit too.

 

So if I did look into DPF removal, it would be on the basis of long-term fuel savings.

 

And if I did, it would probably be accompanied by the Stage 1 remap. Shark tell me that this will be smoke free, whereas the Stage 2 will see "some smoke". I'd also be increasingly nervous of clutch slip with the Stage 2. Not seen the issue mentioned much on tuned CR170s, probably because they have smoother delivery, but it was certainly always an issue on remapped PD130s.

 

On the subject of DPF removal, MOTs, etc etc - that's all been done to death on every motoring forum on t'interweb, I'm fully aware of the all facts, so was hoping not to go through all that again here....likewise with supermarket vs. premium diesel. Those subjects probably rank closely behind "petrol vs. diesel" debates on the scale of futile forum discussions ( No offence to anyone in particular btw !)

On the subject of DPF removal, MOTs, etc etc - that's all been done to death on every motoring forum on t'interweb, I'm fully aware of the all facts, so was hoping not to go through all that again here....likewise with supermarket vs. premium diesel. Those subjects probably rank closely behind "petrol vs. diesel" debates on the scale of futile forum discussions ( No offence to anyone in particular btw !)

 

That's why I didn't mention the MOT etc...

Perhaps we have just been unlucky and the problem may not have been down to fuel issues - it's a component that could have other issues causing the concern.

 

Our last two diesel cars have both had issues with DPF. Both are used on regular mixed journeys - very few short journeys I hasten to add. Regular services, etc.

 

Speaking with a local experienced garage mechanic about the issues, the first question he asked was where we bought fuel from and he suggested we look to buy elsewhere using a brand.

 

I'm not saying the problem has gone away, but we have not had a subsequent "limp home" issue since moving away from supermarket fuel. It's a personal decision and one I'm comfortable with.

 

Given we've done away with supermarket onsite shopping and saved more by not driving to the shops (and ending up buying more than we need) it's a win-win for us personally. 

 

Perhaps I need to do some more work with VCDS to get more insight into the DPF issues.

 

I guess the other effect of DPFs is to mask any minor engine issues that - in pre-DPF days - would have been noticed by an increase in smoke.

 

If you had an issue causing slightly elevated smoke levels, that could cause the DPF to clog more quickly.

But some issues are minor enough not to cause fault codes to be logged in the ECU (an old example being failing MAF sensors).

That's why I didn't mention the MOT etc...

 

Sorry that wasn't aimed at you. Just a general request not to follow that path again

I haven't made any decisions yet...

 

I decided I wanted to fully understand the system, and how it's functioning on my particular car on my typical journeys, before deciding what to do.

Much of the publicised fear of DPFs is based around earlier systems and is probably unfounded now, on the VAG CR engines at least. So it was interesting to read the self-study guides on the CR engine and on the newer DPFs to see exactly what has changed.

 

From what I've read and logged, I'm not worried about the DPF clogging. 

 

What has surprised me though, is just how often it's having to do an active regen. I'd assumed that my longer journeys would be sufficient for most of the soot to be got rid of passively, but to find it's actually doing active regens every 200-300 miles, was definitely a surprise.

This will be causing an increase in fuel consumption - but I don't think I can quantify how much by.

 

I'm having frequent regens in the same mileage as yourself.

 

I'm now used to it happening now and as long as it clears without too much hassle I can live with that.

 

Will keep following this thread to see what decision you make as I'm not ruling out anything longterm. 

If anyone wants to know what the inside of their DPF looks like, have a look at this thread:

http://www.myturbodiesel.com/threads/mkv-dpf-dissection.6854/

 

And here's one having the ash cleaned out of it with a pressure washer:

http://www.myturbodiesel.com/threads/mkv-dpf-washout-and-rebuild.17842/

I'm trying to find out exactly how a driver initiates regen?

You can't initiate an active regen without using VCDS (or dealer computer) AFAIK.

I thought it was mentioned mentioned in the handbook but didn't elaborate.

The handbook tells you what to do when the DPF light comes on, which I believe will be when it's tried an active regen and the filter is still carrying too much soot.  This is in the section which describes the various warning lights on the instrument panel (page 30 in my owner's manual). My understanding is that driving in the way described in that section of the manual is optimal for an active regen (which the car already knows it needs to do) to be successful.

 

As muddyboots says, you can't trigger a regen yourself without VCDS.  The document linked from muddyboots' post #36 describes how to force a regen using VCDS.

Edited 1 July, 201412 yr by ejstubbs

I've never noticed a regen light coming on, but then I've only done 9000km so far.

I'm lucky in that I do very few short trips now and when we move to the country (escape?) my 'short' trips will be 50km return on quiet fwy/hwy conditions.

I'm wondering if the 'bad press' PDFs get relates to PD as opposed to CR engines.

There is no 'regen' light. The light only comes on if there is a problem with the DPF which the car can't sort out for itself. It's a 'DPF error' light.

Edited 2 July, 201412 yr by weasley

Ok.

I still wonder if the CR engines have less PDF issues, or is it too early to say?

Ok.

I still wonder if the CR engines have less PDF issues, or is it too early to say?

They seem far better than the previous generation engines - I've hardly seen any reports of problems with the CR.

I think you're right that a lot of the bad press came about when DPFs were first shoved on as an afterthought to the PD engines, and that worry has stuck.

Reporting back on earlier findings, I seem to be getting 2-3 active regens every week (on average I do around 400-450 miles/week).

So I wonder if anyone with a CR engine has had a PDF problem.

I've never noticed a regen light coming on, but then I've only done 9000km so far.

I'm lucky in that I do very few short trips now and when we move to the country (escape?) my 'short' trips will be 50km return on quiet fwy/hwy conditions.

I'm wondering if the 'bad press' PDFs get relates to PD as opposed to CR engines.

Don't have a diesel car now, but as far as I recall the old 1.9 PD engine which I ran for many miles didn't have a DPF. Don't know if they stuck one on later?

Don't know if they stuck one on later?

They did, yes.

Something's not right if you are getting 2/3 re-gens in a week, unless the mileage you mention is all short stop/start runs. But even then it sounds excessive.

Is it wrong....or is it just that I'm going out of my way to monitor regens, when most people probably wouldn't notice them happening....

Do you only run short start/stop journeys? If you do a long motorway run 15/20 mins no slowing or stopping for hold-up's, you probably won't notice the re-gen, other times you may notice higher rev's when idling and the fans are on.

Do you only run short start/stop journeys? If you do a long motorway run 15/20 mins no slowing or stopping for hold-up's, you probably won't notice the re-gen, other times you may notice higher rev's when idling and the fans are on.

Not at all, my regular commute is approx 40 miles, at least 75% of which is on fast, open rural roads.

But steady cruising, even at 60+, doesn't get the exhaust temps up enough for passive regeneration to occur.

 

I can usually spot the regen by the change in exhaust tone. A quick dip of the clutch to see what the idle speed is confirms, as does VCDS when I check distance since last regen.

Probably worth getting it checked, may be a faulty sensor.