Particulates and regens and my OCD!

**gdallas** · 10-09-2013,07:33 PM

Couple of queries here!

Have been becoming concerned that my car has forgotten how to regen. Could be my OCD! Lol was sitting at 24g the other day, which I felt was rather high. Just so happened to bee working in Aberdeen today, which meant a 100mile each way up the A90 at 75-79mph. for the first half hour I drove in 4^th to keep th revs over 2k. when I arrived home, I measured the soot, it was only blooming at 10g! and this is where my ocd may be kicking in, doesn’t this seem high, following a large journey like that?

some hours later I strapped on the vcds and took it up the motorway for 20 mins, I watched in realtime the soot go all the way down to 1.91g then it kinda bottomed out. What I noticed tho was as I arrived at junction, or whacked it on neutral, any time where there was very low revs, the measured soot began to climb farily rapidly actually. And within a 10 seconds, maybe about 2g. is this normal?

Now, my ignorance here is with reagrds when a regen has completed, or even started, or what actually defines a regen in the first place. I’ve measuring my soot a lot recently, it looks as though my car continuously burns off soot when the conditions are right, i.e. about approx. +2k revs where the exhaust gas temp must be sufficient to burn it off. However, as far as I can glean from my experiments, although my car appears to be continuously regenerating, it only appears to regenerate IF the soot levels fall below a particular low level as my “time/distance since last regen” status is still of large values.

Now I’m particularly concerned as I would have assumed a 2.5 hours journey each way to Aberdeen on a 70 should have “regenerated” the dpf, like completely? That and the fact why soot levels climb back up rapidly scares me a little!

It may be related to me not having adapted my dpf sensor, but im not sure

**Guest 2** · 10-09-2013,07:54 PM

The adaption could have something to do with it, I can feel my DPF doing its thing ~40% full on VCDS. This is only once every 2.5 weeks tho.

All other times its normal and I do one run a week in 4th just to help it along. I do 600 miles a week, 100% motorway, no town.

**gdallas** · 10-09-2013,08:02 PM

How can you tell from vcds that's it's 40 percent full?

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**Guest 2** · 10-09-2013,08:04 PM

It's group 75 in Engine Measuring Blocks .. I'll go out and screen shot now.

**Guest 2** · 10-09-2013,08:09 PM

3rd box along - currently 22.9% full of soot or whatever it is.

Btw - A PM to Crasher would prove useful as he knows his ash from his soot and can advise better than me!

**gdallas** · 10-09-2013,08:18 PM

Ah, what a peculiar name to call it ...

Cheers Bro. I'll check mine now

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**Guest 2** · 10-09-2013,08:19 PM

Thats on my 1.9 A3, I can't see it being much different to your A4, as I said above, maybe a PM to Crasher would prove useful as he knows alot about DPFs and loves(!) them!