Extremely frequent regen - every 30 kilometers

[BogdanB]

Go to settings, Custom engine group, and select Group 0 CRBC,CLHA,CKFC. They are basically the same engine (the 150hp version, 2L also, EA288), but it will also show you the Soot Mass Measured instead of Nox sulfur charge, so you will better understand why the sudden jumps.
Also what are your avearge values for mg/km ? When engine cold vs engine at operating temp.

 

[BillyCool]

Go to settings, Custom engine group, and select Group 0 CRBC,CLHA,CKFC. They are basically the same engine (the 150hp version, 2L also, EA288), but it will also show you the Soot Mass Measured instead of Nox sulfur charge, so you will better understand why the sudden jumps.
Also what are your avearge values for mg/km ? When engine cold vs engine at operating temp.

Thanks for that. I'll see how I get on.

Ref mg/km do you mean MPG/fuel consumption?

 

[SuperV8]

I'm on about 95,000 miles. 2015my

measured soot 35.4g
calculated soot 7.07g
distance since last regen 20.8km

Don't know if measured soot is the same value as ash in the DPF app?

 

[BogdanB]

Thanks for that. I'll see how I get on.

Ref mg/km do you mean MPG/fuel consumption?

My bad as i wasn't clear enough. The value in the upper right corner in the VAG dpf regarding Soot Quantity. The one that says -7787mg/mi in your screenshot. If you leave the app open for a few minutes while driving, it will also show how much soot is produced per mile( or km, depends on settings probably ).

I'm on about 95,000 miles. 2015my

measured soot 35.4g
calculated soot 7.07g
distance since last regen 20.8km

Don't know if measured soot is the same value as ash in the DPF app?

View attachment 25608

The ash should be oil ash volume if I'm recalling correctly ( in VCDS at least ). The measured content of soot doesn't seem right as 35g is way above the limit. Also the differential pressure offset seems odd too. The offset should usually be around a few negative hPa. Definetely not -149.

As from the self study program you also linked, there are two soot load models.

The first model referred is the "Soot Mass Calculated" and the 2nd one is the "Soot Mass Measured" .

Most certainly when people see jumps in their Soot Mass Calculated, it's the 2nd model that is getting to 100% triggering a regen.

 

[SuperV8]

My bad as i wasn't clear enough. The value in the upper right corner in the VAG dpf regarding Soot Quantity. The one that says -7787mg/mi in your screenshot. If you leave the app open for a few minutes while driving, it will also show how much soot is produced per mile( or km, depends on settings probably ).

The ash should be oil ash volume if I'm recalling correctly ( in VCDS at least ). The measured content of soot doesn't seem right as 35g is way above the limit. Also the differential pressure offset seems odd too. The offset should usually be around a few negative hPa. Definetely not -149.

My engine wasn't running.
Like I said: Don't know if measured soot is the same value as ash in the DPF app?

 

[BogdanB]

My engine wasn't running.
Like I said: Don't know if measured soot is the same value as ash in the DPF app?

My edited answer should clarify this probably.
TL;DR: No, measured soot is not the same as oil ash.

 

[SuperV8]

My edited answer should clarify this probably.
TL;DR: No, measured soot is not the same as oil ash.

View attachment 25610

Thank you, I couldn't see the measured soot mass on Brian's screen shot.
There were loads of live data streams to pick from. I'll try and borrow the tool and have a deeper look.

 

[BogdanB]

Thank you, I couldn't see the measured soot mass on Brian's screen shot.
There were loads of live data streams to pick from. I'll try and borrow the tool and have a deeper look.

That's why I told him to change engine group.

 

[BillyCool]

So - here you are. As the car is first started and driven, the calc soot mass is more than the measured and then the measured catches up and becomes the greater figure.

My mg/mi was around 110 when colder or town driving and seemed to drop to around 60 on the open roads. That might explain why it DPF regens more now I'm doing lots of local trips c.5 miles and the car (oil) isn't even up to temp. I used to do a 20 mile commute each was and motorway miles. Now I'm plodding along on rural roads with 30/40/50 limits. I don't even get over 60 and a lot of the time the car doesn't even get the oil up to temp.

I do think that the DPF might be getting more full up as well but I'm open to suggestions.

 

[BogdanB]

If the car hadn't been using abnormal quantities of oil, then your Oil Ash Residue reading might be somewhat accurate and 55% shouldn't be a problem. Otherwise, it will be higher than what's estimated and your DPF might indeed be more full.

 

[cjperks]

A bit late on the response here, but every little helps.

Finally took the DPF out this winter, sent it away for cleaning, and reinstalled.

The removal and reinstall was a massive pain. Even the local specialist garage I spoke to wasn't keen. Did it in the back yard with the car on a mini scissor lift.

Short version: problem still remains. Discussed with the garage as well, and I'm about 95% sure that the problem is simply the engine burning oil and the waste clogging up the DPF. Only realistic fix at this point is engine out and a rebore. I'll probably not do that, and just accept the problem until acute issues start to present.

Root cause (in this case) is probably the extended service intervals (by Skoda) at the start of the cars life causing early wear on the piston rings.


Hope this helps someone!

Perks

 

[SuperV8]

A bit late on the response here, but every little helps.

Finally took the DPF out this winter, sent it away for cleaning, and reinstalled.

The removal and reinstall was a massive pain. Even the local specialist garage I spoke to wasn't keen. Did it in the back yard with the car on a mini scissor lift.

Short version: problem still remains. Discussed with the garage as well, and I'm about 95% sure that the problem is simply the engine burning oil and the waste clogging up the DPF. Only realistic fix at this point is engine out and a rebore. I'll probably not do that, and just accept the problem until acute issues start to present.

Root cause (in this case) is probably the extended service intervals (by Skoda) at the start of the cars life causing early wear on the piston rings.


Hope this helps someone!

Perks

A re-bore is not always 100% required.
Some people just replace rings, and works fine and cures their oil consumption.
Trouble is - you never really know until you're into the engine and can inspect the bores.
If you have severe oil consumption this will damage your DPF - which is also an expensive fix!

edit#
Can see this piston part listed:
"04/13-12/16 001 Dimension group 1 80,920"
So 'guess' that is an oversized piston? - listed at £250 - so £1k additional + machining.
Mahle do some +0.25 and +0.50 but all seem to be out of stock which is strange!

https://www.autodoc.co.uk/car-parts/piston-10629/audi/a3/a3-8v1/55593-2-0-tdi?supplier%5B%5D=10223