Do blocked DPF cause fumes smell in cabin?

[hollyp0p]

I've got an 11 plate 1.6 tdi Fabia estate which I have had since November. 

As I do a fair amount of town driving with blasts at the weekend, so the DPF light has come on I think 3 times since I have owned it and each time prior to the warning light for a few days I get exhaust fumes smell in the cabin when reversing only... Does this smell just relate directly to the blocked DPF?

Light goes out after a good run up abs back on the dual carriageway and no smell afterwards (it's not run with the light on for days and no engine management lights). 

Is there something else that would be causing the smell which needs investigating as I am in two minds about just getting the DPF cleaned but don't want to if it indicates another issue. 

 

Thanks 

[mrgf]

It is more likely you will notice fumes when reversing as basically, you are reversing into the exhaust outlet! 

The Fabia's a/c (At least, on climatronic) Speeds up the interior fan as a kind of cure for this. It goes faster as you engage reverse gear, to suck more fresh air in to the cabin. 

You might be noticing this as you are not so used to a diesel for instance, and notice the exhaust smell more. 

 

This is also one of the reasons you should try not to drive with the tailgate open. The exhaust fumes could potentially be drawn back in to the vehicle and cause problems for the occupants. 

As for smelling MORE during a regen or when it is needed, this may well happen as the engine will try burning more fuel, to heat the exhaust emissions to a higher temperature, to burn off more soot. You normally do this by driving faster, out on duel carriageways, so may not notice extra whiffiness!

 

This in itself does not mean that there are not any holes, etc in the actual exhaust system. The old fashioned way of checking this is to run the engine and try obstructing the tailpipe for a few seconds. The engine might struggle and cut out or you may find it hard to keep the pressure on, with the exhaust gasses forcing you off the pipe but if there is a proper leak, you should then hear the gasses escaping and possibly even hear/see where it happens. If it cuts out, it kind of suggests no leak as the pipe cannot release the gasses and the engine stalls. 

[hollyp0p]

Ok thanks, I've only ever had diesel cars over the last 17 years or so and have not had one that does this before - Although this is the first diesel I've had with a DPF fitted as previous cars were all too old for that kind of technology.

 

The smell isn't slight when this occurs either, it's very pungent and definitely exhaust type fumes not rubber, eggy or raw diesel smells. However like I said once it's been run and DPF light is out, the smell on reversing is gone completely.

 

Any idea if the DPF cleaning additive is safe for the 1.6 TDI engine, like Wynn's which you pop in the fuel tank? I know the handbook says not to use fuel with additives, but not sure if that means things more like diesel + from the posh pumps!

[mrgf]

I use Cataclean, the actual specific one for diesels, not the diesel and petrol version. It seems to help and can be purchased quite economically from a well known auction site. I often buy two at a time as it saves money and the best price seller can be as much as half price anyway! You put the whole lot in a quarter full tank (Approx) And drive for around fifteen mins, more if possible. You then drive as normal, run near to empty and fill again, when needed. I have done this prior to MOT tests and pass without issue. Recently, I had an MOT and failed so the tester ran it on a different branded cleanser, Where he did it static though, he managed to somehow "Blow" The coolant expansion bottle and that had to be replaced. Once replaced, it passed the test but that cost an additional £7 to fix, on top of his £20 for there treatment. Wish I had filled with the Cataclean first! It was a bit unexpected though, as I had someone damage my door and had to have that repaired and the car re-MOT'ed for the insurer to be happy. Due to this, the car had been standing unused, for a number of weeks, then MOT'ed from cold, without any runs, etc. 

[hollyp0p]

Thanks that's handy to know! What engine is in your Fabia?

 

Mine's actual in with my regular garage today to check it over and make sure EGR isn't sticking or another issue which would need resolving. I've told them though that I suspect it might just be in need of a good clean, I've no idea if it's ever had one and we've just hit 90k on the clock so it's got a lot of miles if it's never been cleaned or replaced!

[hollyp0p]

Call from the garage and it#s pretty much worst case scenario, I am gutted!!!

 

Flexi hose coming down from DPF is blowing (small blow), mechanic says due to it all being one part that he doesn't think we can do any cut and fit to replace and that it means new DPF. He was asking though if anyone knows of any easier ways in than dropping sub frame to repair and whether he is right in thinking he is going to need new DPF to repair?

 

Also where's the best place to find myself another DPF, don't mind refurbished if it's from somewhere reputable.

 

Thanks!

[spartacus68]

It should be possible to remove the DPF and catylitic converter without the subframe being removed. https://workshop-manuals.com/skoda/fabia-mk2/power_unit/1.6/55;_66;_77_kw_tdi_cr_engine/exhaust_system/removing_and_installing_parts_of_the_exhaust_system/removing_and_installing_pre-exhaust_pipe_with_diesel_particle_filter_vehicles_with_right-hand_drive/

 

That said, you're paying for labour here, so any temporary fix needs to be ruled out, you'll definitely be wanting to weld in a new flex pipe.

[hollyp0p]

11 hours ago, spartacus68 said:

It should be possible to remove the DPF and catylitic converter without the subframe being removed. https://workshop-manuals.com/skoda/fabia-mk2/power_unit/1.6/55;_66;_77_kw_tdi_cr_engine/exhaust_system/removing_and_installing_parts_of_the_exhaust_system/removing_and_installing_pre-exhaust_pipe_with_diesel_particle_filter_vehicles_with_right-hand_drive/

 

That said, you're paying for labour here, so any temporary fix needs to be ruled out, you'll definitely be wanting to weld in a new flex pipe.

 

Brilliant thanks, I'll email this over to him so he can have a look!

 

I've spoken with a local DPF terracleaning branch who are actually saying they don't think it's worth cleaning the DPF while it's off (they would need to assemble a rig to clean as they don't do the chemical soak and blasting, apparently it often causes damage and gives them more business). He said from my description he thinks DPF is working as it should and that they should look to chop flexi hose and refit new to my DPF as it is and just run it, only to refer to them for diagnostic and cleaning if I get any issues beyond that.

 

So I'm hoping between these two new bits of info that we may be able to save quite a bit of money, and I can bear in mind the cost for a clean if required at a later stage.

 

Does that sound sensible or is it really short-sighted not to just refurb/replace it?

 

[GlenP]

Local main dealer quoted £1389, just to obtain, never mind fit, a replacement DPF, and it would be a like for like swap with a refurbished unit. Apparently, these engines are now classed as too old to obtain a new replacement DPF / CAT assembly. 

 

Salvaged / reconditioned units were coming up on an online parts search at anywhere from, roughly, £250 - £900, without being fitted, and you'd have to make sure the garage you took the car to had the ability to map the replacement onto the ECU, using VAGCOM, or it wouldn't regenerate, when needed, therefore needing replacement much more quickly than should really be the case.

[hollyp0p]

So the last two times it's had a 45 min run up for the day to next city and 45 min back it has caused DPF light to come on after a few days, smelling because of the SPLIT a few days before that. 

 

Is that normal or should it be clearing on a long run without the light having to come on first? 

[spartacus68]

5 hours ago, hollyp0p said:

So the last two times it's had a 45 min run up for the day to next city and 45 min back it has caused DPF light to come on after a few days, smelling because of the SPLIT a few days before that. 

 

Is that normal or should it be clearing on a long run without the light having to come on first? 

 I don't know how often the car should be doing a regeneration. I probably do 300 miles a week, so I suspect it's doing a regeneration at least weekly. This is determined by soot level, engine temperature, etc. The only way to have a definitative check is with VCDS. The DPF light could be linked by Lamba sensors after the DPF and again after the catalytic converter. Again, VCDS would read the fault codes thrown up, otherwise you're just guessing.

 

Try a can of Forte diesel conditioner in the car on a quarter tank, and drive it hard. Forte is good for the injectors, and won't do it any harm. Even treat it to premium diesel and see if that makes any difference.

Edited 13 May, 2019 by spartacus68

[mrgf]

On 30/04/2019 at 10:02, hollyp0p said:

Thanks that's handy to know! What engine is in your Fabia?

 

Mine's actual in with my regular garage today to check it over and make sure EGR isn't sticking or another issue which would need resolving. I've told them though that I suspect it might just be in need of a good clean, I've no idea if it's ever had one and we've just hit 90k on the clock so it's got a lot of miles if it's never been cleaned or replaced!

Mine is a 1.4 tdi Greenline. I notice more smoke/fumes if I use Asda fuel. If I use say, Shell/Esso, etc, never noticed an improvement if used premium fuel over standard, though. You might do on higher tuned variants. 

I had the EGR once, the issue raised again within hours of being driven. I think it only got filthy due to other issues. To this, I paid around £300 for a job that was un-needed. As you now know it is a hole, getting that sorted will be priority.

I think the DPF's self regenerate as you drive on long journeys but stop-start/slow journeys and the need to "Do" the regen becomes apparent. (Light on, drive faster, non stop, for 15 mins etc). This may need doing today, say, even if Saturday (For instance) You drove 150 miles up the motorway, then drive around town again over the rest of the weekend.