Another DPF regen thread i know.

 

 

Bought my RS tdi about 8 month ago with around 85000km (55k miles) on it. 

Regen every 300-370 miles. 

 

Now i get regen every 110 miles. 

11000km (68k miles) on it now. 

 

What can be the cause? 

 

 

Edited 6 July, 20205 yr by Obalaan

MIne has done 6 this week and I want to get it removed and mapped out but cannot find anyone locally to do so ! 

1 hour ago, Chriso said:

MIne has done 6 this week and I want to get it removed and mapped out but cannot find anyone locally to do so ! 

Removing the DPF is an MOT fail in the UK.

On ‎07‎/‎07‎/‎2020 at 00:32, Obalaan said:

Another DPF regen thread i know.

 

 

Bought my RS tdi about 8 month ago with around 85000km (55k miles) on it. 

Regen every 300-370 miles. 

 

Now i get regen every 110 miles. 

11000km (68k miles) on it now. 

 

What can be the cause? 

 

 

what kind of journeys are you doing ? if you're doing lots of slow low miles you  could be filling the DPF up so it has to regen more often to clear it. Over time DPF's eventually fill up and have to regen more often until they are full and then need to be replaced.

also if the previous regen attempt was not successful it will keep trying

 

This may sound like a really stupid question... however how do you know that your DPF is regening (without connecting to the OBD with an app or scanner)?

 

I have owned 2 mk3 Octavia vRS’s and never noticed it happen? Perhaps thats down to my right foot made of lead and frequent long journeys, again with the foot down.... but I would have thought I’d have noticed at least once?

 

Thanks
Matt

23 minutes ago, MTwedVRS said:

This may sound like a really stupid question... however how do you know that your DPF is regening (without connecting to the OBD with an app or scanner)?

 

I have owned 2 mk3 Octavia vRS’s and never noticed it happen? Perhaps thats down to my right foot made of lead and frequent long journeys, again with the foot down.... but I would have thought I’d have noticed at least once?

 

Thanks
Matt

The car will idle at about 1000rpms and the radiator fan will activate.

3 minutes ago, Ecomatt said:

The car will idle at about 1000rpms and the radiator fan will activate.

I see... ok thanks probably has happened a few times then and I haven’t noticed!

6 minutes ago, MTwedVRS said:

This may sound like a really stupid question... however how do you know that your DPF is regening (without connecting to the OBD with an app or scanner)?

 

Another stupid question: Is your VRS a diesel?  You will not get a regen if it is petrol.

 

10 minutes ago, MTwedVRS said:

I have owned 2 mk3 Octavia vRS’s and never noticed it happen? Perhaps thats down to my right foot made of lead and frequent long journeys, again with the foot down.... but I would have thought I’d have noticed at least once?

 

There are 2 kinds of regen: active and passive. Passive happens automatically when a sufficiently high temperature is reached in the DPF. As far as I know there is nothing to indicate that this is happening. Active regens are needed from time to time, as the passive regens are not normally enough to take care of all the soot that builds up. When an active regen is in progress the idling speed is a bit faster than normal: 1200 rpm rather than about 900-1000. You may notice the faster idling speed if you have a DSG and are coasting in eco mode. If you stop before the active regen has finished there will be the noise of a fan running and a burning smell.

 

On 10/07/2020 at 14:59, Gissin said:

Over time DPF's eventually fill up and have to regen more often until they are full and then need to be replaced.

 

The purpose of the regen is to burn off soot which builds up relatively quickly in the DPF. Unfortunately this produces ash which is not eliminated by the regen process. It is the build up of this ash in the DPF which eventually requires replacement of the DPF.

 

3 minutes ago, OldBoyScout said:

 

Another stupid question: Is your VRS a diesel?  You will not get a regen if it is petrol.

 

 

There are 2 kinds of regen: active and passive. Passive happens automatically when a sufficiently high temperature is reached in the DPF. As far as I know there is nothing to indicate that this is happening. Active regens are needed from time to time, as the passive regens are not normally enough to take care of all the soot that builds up. When an active regen is in progress the idling speed is a bit faster than normal: 1200 rpm rather than about 900-1000. You may notice the faster idling speed if you have a DSG and are coasting in eco mode. If you stop before the active regen has finished there will be the noise of a fan running and a burning smell.

 

 

The purpose of the regen is to burn off soot which builds up relatively quickly in the DPF. Unfortunately this produces ash which is not eliminated by the regen process. It is the build up of this ash in the DPF which eventually requires replacement of the DPF.

 

Yes mines diesel and thanks for the detailed response! 

If you have not noticed any regens in progress it is probably not that surprising. The increased idling speed is easy to miss, and you are only going to be aware of something more obvious if the regen is interrupted by stopping the engine before the regen has finished. I had owned my car for a fair while before I noticed this for the first time. DPFs on earlier cars can be more problematic, but for most later models they seem to work pretty seamlessly and for me regens are not a cause for concern. I only do a small annual mileage with lots of short trips, but the car takes care of the regens OK, and I have never seen a DPF warning or needed to intervene in 4.5 years of ownership. 

 

I can also hear engine sounding different when I press the accelerator if active regen is in process. That is the 3rd sign of active regeneration on my car (besides already mentioned two). 4th is that if regen is active, Start Stop will be turned off automatically.

Put VAGDPF to work for custim group 0 and you ll see soot mass measured instead of NOx.

Monitor if soot mass measured raises faster than calculated and report back.

 

 

What is your differential pressure at idle right after a regen ?