What/how does regeneration work?

[tram]

I am thinking that this is to do with the particulate filter getting time for a clean, so then the engine does something to burn the soot away. I only do short journey mostly. I am thinking that the engine will only decide to regenerate if it feels it is going to get a good long hot steady run?

 

[BAZT6]

You will get an alarm up when the engine is ready for a regen, picture of the DPF and a message. Best thing to do is not leave it to long but get out on to a decent bit of road and just run it at about 3000 rpm, light will go out when the DPF has cleared 20 mins or so. Your short journeys are the problem as the exhaust is not getting hot enough for long enough, but they don't tell you this when you are buying a modern diesel. My A4 blinded its DPF eventually so I removed the DPF cut the end off and drilled the guts out, welded end back on, blanked off EGR and got car remapped. Difference was chalk and cheese, car was so much better to drive. Still passed MOT on emissions but does smoke when pushed hard.
Baz

 

[RattyMcClelland]

You will get an alarm up when the engine is ready for a regen, picture of the DPF and a message.

You won't get any warning on the dash. Not even on the t5.
The dpf Regen's about twice every tank of diesel and only when conditions are met and diesel is above 1/3 full tank.

 

[BAZT6]

Thats a poor system, the 2 Audis that I have had DPFs in both with PD engines have put a message up to let you know that a regen is in progress, when I have seen this I try to drive enough miles to clear the alarm in one go. T6 is a different engine to the Audis though with more emission control.
Baz

 

[Pauly]

Agree with @RattyMcClelland you only see the dash warning light if a regen is overdue because the conditions have not been met for a while ie low fuel level or short trips etc

 

[Grainfoot]

No lights on dash but but regeneration occurs very regular. Sometimes after 50mile drive pull into driveway and fan comes on and assume regeneration is in progress. Only had van a few weeks but this occurs very regular .

 

[danny1313]

Is it possible for a regen to occur straight away after cold start-up when van is sat idling on the driveway? Or would it only kick in when engine is warm/moving?
(2016 T6 140)

 

[Howzat]

It can start from cold. You'll notice the revs increase slightly on idle and the van will get up to temperature quicker because the van is injecting extra fuel to get the van up to temperature so it can burn off the soot. It'll take forever to regen at idle so if you notice it's trying it's best to take it for a run keeping revs above 2k for about 20 minutes.

 

[danny1313]

Thanks Howzat, I’m hoping this explains a couple of very smoky startups over the last couple of months. Plumes of dense acrid white smoke that smells like firefighters/charcoal. Can’t say I noticed much of an increase in the idle speed but it’s possible. Seemed to smoke for about 5 mins not sure how long a regen should typically take.

 

[Howzat]

You shouldn't be seeing white smoke (or is it steam?)
Water could be getting in your engine which could be disastrous.
Get that checked.

 

[Dellmassive]

Thanks Howzat, I’m hoping this explains a couple of very smoky startups over the last couple of months. Plumes of dense acrid white smoke that smells like firefighters/charcoal. Can’t say I noticed much of an increase in the idle speed but it’s possible. Seemed to smoke for about 5 mins not sure how long a regen should typically take.

That may be diesel smoke....?

Possibly a leaky injector?

Can you get a video clip on your phone?

 

[danny1313]

Thanks both, I not sure what it was tbh, but definitely had a different smell to usual, I'd have assumed steam wouldn't alter the smell so much?
I'll try and take a video next time, it's only happened a couple of times on start up in 4 months, so I was thinking (hoping) it may be a regen.
Is the check for water in the engine checking for oil filler cap residue?

 

[danny1313]

If I buy a Carista, is there a log of the regen cycles - wondered if that might enable me to pinpoint whether it was a regen or not.

 

[Howzat]

The smell will only come with the regen so that's probably what was happening but the engine working harder might be showing up another issue that is the cause of the white smoke. I think the van logs the last time regen was run which can be seen with a diagnostic tool.

 

[danny1313]

That may be diesel smoke....?

Possibly a leaky injector?

Can you get a video clip on your phone?

Vans not smoked for a while, but noticed last couple of days it's been a bit smokey on start up....it's not had a long drive for several weeks so maybe (and hopefully) just needs a good run, the smokey exhaust fumes stink.

 

[Dellmassive]

That's not right, very smokey. What was the outside temp?

 

[danny1313]

I think it was about 7-8 degrees, fairly damp air.

It was serviced a couple of months ago, no error codes noted, but I'll give it another scan today. Engine seemed to be running ok, not particularly lumpy so don't think it's injector or glow plug.

 

[danny1313]

Found a few posts on facebook with similar, mentioning potential causes as dripping injectors or intercooler, or maybe just 'normal' condensation in winter weather......hoping it's the later - will give it a good run to see if it improves.

 

[Drive Wayne]

Did you get a Carista Danny? They do tell you how much soot is there and when the last 'regen' happened. You can also force a regen on them when you know you have a good 20 minute drive on a motorway or faster road. Mine will do a regen while not up to temp, usually when you have just got to Morrisons or to take the dog a walk! The revs go up to nearly 1000 instead of the usual 900 on idle. Our van does too many short journeys, regens every 130 miles on average. For £35 Carista is a very worthwhile investment, for many reasons.

 

[danny1313]

No in the end I used an old ELM327 with the VAG DPF lite android app which seemed to indicate it wasn't a regen taking place. Think I'll get a carista though as maybe it has access to more data.