Hi all,  can anyone make sense of my dpf soot reading from main dealer as I had it booked in for intermittent fumes in car only to be told on test drive they couldn't smell fumes in car. However I did ask for the soot reading but I can't make out if it's blocked or ok. I'm thinking it's blocked and back pressure is causing fumes out the spindle coming out the turbo. Any help would be appreciated.

No idea on the values but if it’s blocked then it would pop up as an error id like to think.

 

Ignoring that side of things have you changed pollen filter recently and is your air quality sensor working? I believe when air quality sensor is working correctly it puts the car into recir mode automatically.

 

Is it 100% coming from your own car? If you were out driving when no one’s about and you can smell it then it’ll be your car.

 

Also not to sound rude but can others smell it in your car or just you? Could have been behind a stinky vehicle now you are smelling for it, if that makes sense 

Could it be a damaged/cracked flexi joint on the exhaust?

Definitely coming from my car can smell when I'm only person driving on the road. 

Can sometimes smell it getting out the car.

Had various dealers say they have looked at exhaust system but can't find any leaks.

17k on clock when purchased 6 months ago 36k on clock now.

fumes slightly better but still there.

Thinking main dealer don't want to pay and fit new dpf. 

Ideally would like to know what that soot reading means.

 

 

Hmm, next things I’d try then would be start the car and lift bonnet on and have a smell around but make sure it’s not a windy day just on exhaust your exhaust fumes don’t get blown forward.

 

Secondly have the air controls set to recirculating only then turn it off and keep it off then go for drives.

 

If you smell fumes in your engine bay then it’ll be a case of trying to find it, maybe find a garage which can put a probe around to see if that can detect fumes (I’m sure such a device exists)

 

I think it’ll just be a case of hunting, unlikely to be DPF issues at such low mileage tbh, if it was 360k miles then yeah

Have checked pretty much everything I can only smell I can smell is by the spindle coming out the turbo when under the bonnet which is why I'm thinking dpf might be blocked. Also mpg is only about 38mpg.

Could be the last owner did a lot of stops starts. 

10 minutes ago, Mark156 said:

Have checked pretty much everything I can only smell I can smell is by the spindle coming out the turbo when under the bonnet which is why I'm thinking dpf might be blocked. Also mpg is only about 38mpg.

Could be the last owner did a lot of stops starts. 

If DPF is blocked they’ll be errors and lights galore, does your fan run when you stop and turn ignition off?

 

If so that’s doing a regen which does smell funky but only outside (or should be)

 

Might be worth giving it the italian tune up for 15 minutes anyway, if you don’t have country lanes then go on the motorway and keep it in 3rd or 4th so the RPM’s over 2-3k.

 

Have you tried recirculating mode on for air vents?

 

Pull your pollen filter out too, but do it correctly by placing cardboard under pollen filter first! Then bring out pollen filter on its own!

Cheers for help but have tried all off the above, it does do a lot of regens every day which does make it produce more exhaust fumes and not just a smell of the exhaust getting hot but raw exhaust fumes.

I do around 200 miles a day mix of motorway and other driving as I'm a taxi driver.

Funny thing when Skoda sold it to me they let it slip that they had only just sold it to another customer but she returned the car. Asked why he said oh I think she didn't like the colour. What a load of crap they knew this had problems but thought they'd just palm it off on another customer. 

My fault for buying blind.😡

 

@Mark156  Does your car go through AdBlue at the sort of rate you would expect it to?

The DPF readings show that the measured soot is very low, although it should not be negative but the calculated is high, over the regen threshold, as it triggers on the calculated and not the measured reading that is why your car is constantly trying to regen, the fumes given off are fairly noxious and that is why you are smelling them in the cabin, also the bodies defence mechanisms put you on high alert when you smell fire (or hear the roar of a predator) thereafter just a whiff is enough to trigger your reaction.

 

Its possible that someone may have tried to remove the DPF or have it in some way disabled via a software patch and it has gone awry, the negative measured soot reading is implausible, at the very least the differential pressure sensor will need the adaption routine running to create the correct calibration offset.

Do you notice the same smell outside the car as well?

 

It sounds to me like as well as a possible exhaust leak, the car cant be running right as modern diesels are very clean. I don't smell mine at all, in fact I have to have the tailpipe in my face to be able to smell anything and I think I am quite sensitive to the old sickly diesel fume smell.

Hi JR

Cheers for your post, will admit didn't quite understand it all.

The car was only just over a year old when I bought it from Skoda, so don't think the dpf has been messed with and can't see any welding down the back of what I can see.

Would you mind simplyfing which readings are off and what the should be reading so I can go back to Skoda on this one.

Cheers.

Yes it does drink add blue at the normal rate.

 

1 hour ago, Mark156 said:

Would you mind simplyfing which readings are off and what the should be reading so I can go back to Skoda on this one.

 

Volontairement!

 

Soot mass measured being a negative value.

 

It is not measured as such but based on how resistant to flow the DPF matrix is, to do that there are 2 pressure sensors, one before and one after the DPF the difference between them (the differential hence "differential pressure sensor) is the pressure drop across the DPF or its resistance to flow, how bunged up it is with soot (which is removed during a regen) and oil ash which isn't.

 

You cannot have a negative reading meaning a lower pressure on the engine side than the outlet of the DPF.

 

A new sensor has to be adapted (a VCDS routine) to atmospheric pressure and the outputs of the pre and post DPF sensor.

 

That probably hasn't simplified things but it was the simplest way I could describe it.

 

It is usual to see the (not) measured soot value being less than the calculated (due to passive regeneration) but not a negative figure.

Thanks JR 

That gives me something to go with when I contact Skoda again.

Really appreciate your help thank you.

My pleasure! Thanks for the thanks!

If it is just the smell of petrol. Check if the plastic isolation at the tank/petrol inlet is in place.

19 minutes ago, Italiandriver said:

If it is just the smell of petrol. Check if the plastic isolation at the tank/petrol inlet is in place.

There are much bigger problems if he is getting Petrol fumes 😂