Is my DPF regen too often?

[310golfr]

On 07/11/2021 at 13:59, BogdanB said:

A regen can indeed complete at idle. But not in 10 min. It usually takes around half an hour. 

I have watched a lot of regents using vag DPF / vcds. 

At idle, it struggles to keep the temperature up and it uses way more fuel for the post injection. 

While doing it on the highway, it does minimal post injection and it finishes in around 10 to 15 min. 

i've found that once the engine is up to temperature, a regen at idle is quicker than a regen while driving,

this is with monitoring with vag dpf app over 14,000 miles from new and virtually all town driving.

 

This is obviously the opposite to what ever one thinks,  ie  you must drive the car at over 2000 revs  on an extended motorway run etc

 

l've thought about why idle is quicker and i think when driving at speed the airflow through the front grill cools the engine, so maybe this is the reason 

 

Also mine is a 2019 euro 6 engine, i've heard that manufacturers have learnt from there past mistakes and dpf are now  fitted closer to the engine to retain heat better

 

have you watched regens on both euro 5 and euro 6 engines ?, maybe there is a difference 

 

[nta16]

Check, but I think a regen will stop before it's finish if your fuel level is low, always have say a minimum of a quarter of a tank (just for the sake of a measure) and if the running conditions aren't right.

 

The regen conditions want to be as constant and consistent as possible, and it makes it easier on the car and it's computers if you have minimal electrics and other operations going on.

 

Can't dispute 310golfr figures but doing a regen at idle is wasteful and potentially hazardous to surroundings and people, remember if you're standing or sitting there all that diesel exhaust **** is going to your lungs a lot less diluted than on the open road where you're also putting the fuel to more use.

 

As well as considering what comes out you have consider what's going in, cleaner in is better so regular servicing using good quality engine oil changed in a timely manner, same for air filter and cleaning of injectors and sensors, general maintenance of hoses, pipes, connectors and gasket and seals.  

 

Regular use (you decide what you can put up with as regular) of 'super' diesel fuel or perhaps an additive must be better based on my experience of driving my wife's previous car that was a diesel, accelerating at a test location with standard diesel would give a cloud of black smoke but when using the V-Power on the very few times when I dove the car and needed to fill the tank it was a cloud of silver-grey.

 

On a road I saw an Aldi putting out the most black smoke I'd ever seen from a car, then realised it was a neighbour's car, it's all black with smoked black rear number plate, I now wonder if the car was originally white.

 

[BogdanB]

59 minutes ago, 310golfr said:

i've found that once the engine is up to temperature, a regen at idle is quicker than a regen while driving,

this is with monitoring with vag dpf app over 14,000 miles from new and virtually all town driving.

 

This is obviously the opposite to what ever one thinks,  ie  you must drive the car at over 2000 revs  on an extended motorway run etc

 

l've thought about why idle is quicker and i think when driving at speed the airflow through the front grill cools the engine, so maybe this is the reason 

 

Also mine is a 2019 euro 6 engine, i've heard that manufacturers have learnt from there past mistakes and dpf are now  fitted closer to the engine to retain heat better

 

have you watched regens on both euro 5 and euro 6 engines ?, maybe there is a difference 

 

Mike's euro5 andI get the most efficient regents when driving at around 60-80kmh.  About - 2600 3000 mg/min. (once it's up to temp) 

Edited 8 November, 2021 by BogdanB

[The1effect]

       A quick interesting update. The regeneration started before reaching home 😒 after 45 min of traffic. Lasted at least 15 min. The exhaust gas temp in bank 1 sensor 3 didn't go over 600 degrees C but stayed in that range. After those 15 min the rpm start dropping the device showed that generation was still happening but was passive and temp drop to 250 c , after another 5 min regen was stopped so maybe is better to leave it another few minutes after is finished. Interestingly the oil temperature drop from 100 to 94 while regenerating so it doesn't seem to have any effect on engine this process 

[disherwood]

On 02/11/2021 at 14:10, gm73 said:

I sold my 15 plate 1.6 TDi CR with 200k miles

on it and it it constantly regenerated so I wouldn’t worry about it. The new owner has covered another 10k and it’s still going strong with no DPF issues. 

 

GM79 thank you for your positive pragmatic comment...

I’ve just purchased an octavia estate 2016 1.6 diesel with 71k miles and am somewhat bemused

i experience a “regen” or something associated with the dpf after short runs ..the car fan sat running after a i stopped and i noted the dpf to be very hot.....

 

how long did you own your 200k miles diesel for some time......if so it is reassuring to know i can basically monitor / learn about it without getting worried

[disherwood]

On 12/11/2021 at 17:14, The1effect said:

       A quick interesting update. The regeneration started before reaching home 😒 after 45 min of traffic. Lasted at least 15 min. The exhaust gas temp in bank 1 sensor 3 didn't go over 600 degrees C but stayed in that range. After those 15 min the rpm start dropping the device showed that generation was still happening but was passive and temp drop to 250 c , after another 5 min regen was stopped so maybe is better to leave it another few minutes after is finished. Interestingly the oil temperature drop from 100 to 94 while regenerating so it doesn't seem to have any effect on engine this process 

 

Thanks the1effect.......what software app are you using and obd

 

many thanks..

[BogdanB]

You can use VAG DPF app together with an ELM327 Bluetooth device

[The1effect]

16 hours ago, disherwood said:

 

Thanks the1effect.......what software app are you using and obd

 

many thanks..

This is stand alone device autel maxi link 720ml if I remember correctly, no phone or pc

[gm73]

On 20/04/2022 at 17:56, disherwood said:

 

GM79 thank you for your positive pragmatic comment...

I’ve just purchased an octavia estate 2016 1.6 diesel with 71k miles and am somewhat bemused

i experience a “regen” or something associated with the dpf after short runs ..the car fan sat running after a i stopped and i noted the dpf to be very hot.....

 

how long did you own your 200k miles diesel for some time......if so it is reassuring to know i can basically monitor / learn about it without getting worried

I owned the car for 4 years and it was a taxi so lots of short journeys.  I made sure that when the regen began I always drove the car until it had completed and that I always completed one motorway journey per day. 
 

I was getting at least one regen per day. 
 

There’s no point in getting worried about something that probably won’t happen. 
 

I only had the DPF light come on once and a quick Italian style blast over some B roads sorted it. 

[cybernck]

Hello, long time forum lurker and a 2015 Skoda Octavia Mk3 vRS Diesel owner for a year now.

It's been my dream daily car since its debut but unfortunately I've been burdened by both high fuel and high oil consumption since the first day of my ownership.

 

I've done a lot of research and it looks like not much can be done about the oil consumption (6 liters on 15,000 km - if I've kept track correctly) without an engine rebuild.

 

On the other hand, I've traced the high fuel consumption (between 1 and 3 liters over what board computer states and what I would expect) to DPF regenerations happening far too often.

 

I've recently equipped myself with Vgate Pro and VAG DPF app, so I've been able to confirm that the regeneration is taking place almost non-stop.

Oil ash residue is a bit high for the mileage (204,000 kilometers) at 62g or 77% but other VAG engines seem to function normally with that sort of oil ash residue.

However, what confuses me is the soot residue gets a sudden spike from 8g to 23g and starts the lengthy regeneration process. Sometimes it drops down suddenly as well.

 

I'm failing to understand if the DPF filter is actually clogged OR if it's the engine oil burning causing it OR if there's a problem with some DPF sensor.

The last thing I want is to clean the DPF filter or even do an engine rebuild and have the same issues coming up!

 

Thanks.

[fr1nklyn]

7 hours ago, cybernck said:

Hello, long time forum lurker and a 2015 Skoda Octavia Mk3 vRS Diesel owner for a year now.

It's been my dream daily car since its debut but unfortunately I've been burdened by both high fuel and high oil consumption since the first day of my ownership.

 

I've done a lot of research and it looks like not much can be done about the oil consumption (6 liters on 15,000 km - if I've kept track correctly) without an engine rebuild.

 

On the other hand, I've traced the high fuel consumption (between 1 and 3 liters over what board computer states and what I would expect) to DPF regenerations happening far too often.

 

I've recently equipped myself with Vgate Pro and VAG DPF app, so I've been able to confirm that the regeneration is taking place almost non-stop.

Oil ash residue is a bit high for the mileage (204,000 kilometers) at 62g or 77% but other VAG engines seem to function normally with that sort of oil ash residue.

However, what confuses me is the soot residue gets a sudden spike from 8g to 23g and starts the lengthy regeneration process. Sometimes it drops down suddenly as well.

 

I'm failing to understand if the DPF filter is actually clogged OR if it's the engine oil burning causing it OR if there's a problem with some DPF sensor.

The last thing I want is to clean the DPF filter or even do an engine rebuild and have the same issues coming up!

 

Thanks.

You may have issues with any of the sensors on this mileage, but your constant regens are caused by the excessive oil consumption, sorry 😕

 

VAG DPFs at 80% usually need replacement or cleaning.

 

I am not even sure should you change your oil or only the oil filter when you add more oil between changes than when you do a service. But that’s another story.

 

If you can get someone with VCDS to run a diagnostic and see are there any logged errors that would give  you an idea is there a problematic sensor or not.

Edited 6 November, 2022 by fr1nklyn

[cybernck]

Hi, thanks for the reply.

 

Did you mean that the oil consumption is the culprit directly or by way of getting the DPF clogged up? Or in other words, do you think constant regenerations would still happen even with a fresh clean DPF?

 

I don't find it logical that 0.005 liters of oil per 1 liter of diesel can create such a havoc really 😃

 

As far as I know, the diagnostics don't bring up any issues with DPF related sensors.

 

 

[varooom]

The oil ash that your car thinks it has, is from the engine oil, hence why low oil ash oil was created for these engines.

 

You said your car drinks lots of oil, so it has to be exiting somewhere, it's hitting the exhaust and choking it.

 

That calculated value of 62g (77%) is just an estimation from time/distance the ECU calculated (not measured) you may find that your actual physical amount is 124g (154%)

 

Not saying this is accurate, as I cannot see either, but odds are high that it is clogged up.

[PetrolDave]

7 hours ago, cybernck said:

Did you mean that the oil consumption is the culprit directly or by way of getting the DPF clogged up?

By way of getting the DPF clogged up, by producing extra oil ash.

3 minutes ago, varooom said:

You said your car drinks lots of oil, so it has to be exiting somewhere, it's hitting the exhaust and choking it.

 

[cybernck]

Yes, I agree with that. But the point is that the ash residue has developed over the course of 200k km (or probably less, as it had already been like it when I got it back at 187k).

 

So, the question is - if I get the DPF cleaned, will it be fine for the next 50k or so? Or will engine oil trigger the regenerations straight away anyway?

[varooom]

18 minutes ago, cybernck said:

Yes, I agree with that. But the point is that the ash residue has developed over the course of 200k km (or probably less, as it had already been like it when I got it back at 187k).

 

So, the question is - if I get the DPF cleaned, will it be fine for the next 50k or so? Or will engine oil trigger the regenerations straight away anyway?

You could clean or remove the DPF, but not actually going to be fixing the cause of the issues.

 

Ideally you need both things doing, sort the engine and clean DPF.

 

But it's your car and your money, cleaning just the DPF will be a short term solution, as the oil ash will quickly build up and regens will be often.

[cybernck]

You're telling me what I already know fully well.
 

But opening the engine is not an option, so I'm trying to establish if it's worth doing *anything* to the car, considering there's a big service coming up very shortly as well.

 

It must have been buring oil already long before I got it anyway. The car was on Skoda's dreaded 30k km "flexible servicing interval", which is known to kill the badly designed oil piston rings.

[cybernck]

On 02/11/2021 at 15:50, BogdanB said:

When my DPF was clogged this is what would happen: 

1) Regen running, only completing on idle. 

2) Soot mass calculated steadily going up 

3) Soot mass measured spiking to almost 100% ( 24g) when starting to drive away 

4) Few seconds into driving, a new regen starting, triggered by soot mass measured, even if soot mass calculated was at around ~5g

 

@BogdanB- Hi, it looks like I'm experiencing exactly the same symptoms and somewhere else I read that you scheduled the engine rebuild soon, due to high oil consumption - so it's exactly the same case as well.

 

I'm just wondering if you did get your DPF cleaned last year and - if so - what's has it been like with DPF regens since then?

 

Thanks.

[Ootohere]

@cybernck what type of big service has your car coming up.   Nothing about VW group services are big.  Cam belts / water pumps cost money.     Not like a Big BMW serviced where all fluids and bulbs are changed if owners are stupid enough to pay for that.   As to long life services and oil changes.  Nothing wrong with them where a driver covers lots of miles / km in a year.  It is those that do not think that might not drive far and leave the oil and filter to be changed every 2 years to that can be the issue.   Or drive a diesel to save money without understanding servicing costs and emission controls. 

Edited 6 November, 2022 by roottoot

[Ecomatt]

6 hours ago, cybernck said:

You're telling me what I already know fully well.
 

But opening the engine is not an option, so I'm trying to establish if it's worth doing *anything* to the car, considering there's a big service coming up very shortly as well.

 

It must have been buring oil already long before I got it anyway. The car was on Skoda's dreaded 30k km "flexible servicing interval", which is known to kill the badly designed oil piston rings.

A DPF is a filter and will eventually block up again. If it is blocked then it needs cleaning. No one can predict how long it takes to block up again as that will depend on driving style etc.

If you do not clean it out it can lead to other damage and even a fire in extreme cases. But mostly it will just go into limp mode and prevent the engine from damaging itself.

[cybernck]

@roottootYes, by big service  I meant cambelt, waterpump etc at 210k km (as compared to the small service which is just oil and filters). Just a terminology we use here.

 

It's a general consensus here on the forum that it's the 30k km service interval that kills these engines.

 

@EcomattSure, it will eventually clog up again, be it in 1k, 10k or 100k kilometers. But my question is if it will operate fine until it gets clogged up again or will the temporary soot levels still be high and trigger frequent regenerations just due to the excessive engine oil consumption.

[Ootohere]

@cybernck interesting to find out what the consensus is on this forum.   Who is we regarding big and small services and where is here?

[Ecomatt]

9 hours ago, cybernck said:

@roottootYes, by big service  I meant cambelt, waterpump etc at 210k km (as compared to the small service which is just oil and filters). Just a terminology we use here.

 

It's a general consensus here on the forum that it's the 30k km service interval that kills these engines.

 

@EcomattSure, it will eventually clog up again, be it in 1k, 10k or 100k kilometers. But my question is if it will operate fine until it gets clogged up again or will the temporary soot levels still be high and trigger frequent regenerations just due to the excessive engine oil consumption.

My understanding is that the soot levels will be reset once clean and the car will continue to regen every 270 miles give or take. The extra oil burnt will not make too much difference as there is only a small amount. If you think how many litres of fuel is burnt per how much oil is burnt. The oil quantity is very dilute in comparison and wouldnt make a huge impact.

[cybernck]

Yes, that's my understanding as well, considering I estimate it at about 0.005 liters of oil per 1 liter of diesel.

Will be a touch more oil per liter of diesel once the constant regenerations stop and the car starts using less fuel.

 

[J.R.]

Why do you think there was such a need to create low SAPS oils if combusted engine oil has a negligable effect on a DPF?

 

Its like me saying that 1mg of arsenic is nothing compared to the 2000g of water I drink a day.