pewe
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| posted on 12/6/14 at 10:43 AM |
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Tin-top Diesel Particulate Filter.....
Just arrived back last night from Newcastle completing a move South for my aged aunt.
Eventful journey as it turned out.
We were in her diesel Pug 406.
She's only ever really driven it locally, short journeys at that and 27k miles from new 6 years ago.
Over the weekend I was telling her how that sort of running wasn't good for a diesel.
Anywho lane 3, M1 in last night's rush-hour and it suddenly gave a big "POCK" and the dash lit up like a Christmas tree.
Power dropped momentarily which had me scuttling for lane 1.
We managed the next exit (22) with the intention of turning it off and re-starting it.
By the time we'd wound our way to a suitable location there was a small industrial estate and aunty spotted an MOT garage.
I caught him just as he was closing, describing the problem and much as expected he said "Diesel particulate filter".
I asked him if there was any problem driving it to Reading and he said not really but if I drove it for 30 miles at 3k revs, then turned it off it
should clean out the filter.
As it turned out he was 99% accurate - it actually took 60 miles!
So rather than having to visit a main stealer immediately we were able to continue our journey and by the looks of it avoid her having to shell out
for a new filter - c.£400 IIRC.
Thought you might like to know that....
Oh and a thousand thanks to TEK TestStation in Markfield for his advice - top man 
Cheers, Pewe10 
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DW100
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| posted on 12/6/14 at 11:05 AM |
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Yes we are seeing huge problems in the trade with diesels never being driven in the right way to enable the particulate filter to regenerate
properly.
This car obviously grabbed the chance to give it a go. You are lucky that it wasn't too clogged for the car to allow the process to start. If it
doesn't regen then it keeps collecting soot till its clogged and the car doesn't run.
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D Beddows
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| posted on 12/6/14 at 11:36 AM |
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and in those 60 miles you just pumped most of the particulates the DPF had been protecting the planet from into the atmosphere anyway...... they are a
complete nonsense and the work of the devil!
You were lucky, it's been my unfortunate experience that once the dash lights up and the car goes into limp home you often need more than just
revving the nuts off it for 30-60 miles - you don't always need a new DPF though as there are quite a few garages that have the equipment to
revive a properly bunged up one.
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DW100
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| posted on 12/6/14 at 11:46 AM |
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Don't believe the hype, it is unfortunately a common practice for garages to use a pressure washer to clean the particulate filter and all the
collected crap just gets washed down the drain.
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D Beddows
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| posted on 12/6/14 at 11:53 AM |
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I actually watched it being done properly on one of my company cars, not sure I would have enjoyed it if it had been my car though  - not to say
that a lot of people don't just use a pressure washer obviously!!
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DW100
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| posted on 12/6/14 at 12:04 PM |
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What do you mean by properly?
A static regen?, where the car sits there at 3000 rpm for half an hour, pumping excess fuel into the system so that it burns in the exhaust system, to
get the temperatures up to the point where the soot will burn and turn into ash? With the associated risks of fire and bits melting?
Or by pumping additives in that supposedly lower the burn point of the soot?
The reality is the system isn't suitable and is more about politics than a proper workable solution.
[Edited on 12/6/14 by DW100]
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D Beddows
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| posted on 12/6/14 at 12:15 PM |
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Option 1  - wasn't my car so I just smiled and stood well back! It worked as well....... then 3 weeks later the turbo actuator failed -
possibly related admittedly but who knows! No it's not 'proper' fix in the true sense of the word I agree and the whole DPF
thing is, as you say, a complete nonsense and all about green politics rather than the reality of what actually happens.
After my experiences with that Passat I definitely wouldn't buy a 'modern' diesel with my own money however!
[Edited on 12/6/14 by D Beddows]
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mcerd1
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| posted on 12/6/14 at 12:29 PM |
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quote:
Originally posted by DW100
Yes we are seeing huge problems in the trade with diesels never being driven in the right way to enable the particulate filter to regenerate properly.
they tell people to drive slower and keep the rev's low to save fuel, then they stick on a DPF to make what comes out the back 'a
bit' nicer to breath in
but the only way to keep the DPF clean is to get it nice an hot - normally by revving it for a bit (which destroys your average fuel economy) - so its
really catch 22
my mum's 59 plate 1.6D polo has been in for 3 separate recalls over this (each one an ECU update for the DPF) VAG just couldn't seem to
get it right 
at one point it was so bad you could have driven it up and down the motorway all day at normal revs (~ under 4k) and it would never get hot enough to
regenerate....
between the DPF, EGR and variable vane turbo's - I decided the answer is to stick to petrol cars !
[Edited on 12/6/2014 by mcerd1]
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DW100
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| posted on 12/6/14 at 12:38 PM |
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I thought that was what you meant.
Most manufacturers have now removed the ability to do a static regeneration from their diagnostic equipment because of the risks.
Only option now is a forced regeneration that takes two technicians around an hour. Its done on a road test so that airflow around the car stops
things getting too hot. The system checks the differential input and output pressures of the particulate filter and if the filter is not too blocked
it will allow the procedure to be started. The car has to be driven above a set speed and the second technician uses the diagnostic laptop to command
a regeneration. If the car drops below the critical speed or the exhaust temperatures get too high it will abort the regeneration and you have to
start again.
If it fails this procedure its a new filter.
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DW100
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| posted on 12/6/14 at 12:43 PM |
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There are new rules coming into the MOT that mean a particulate filter cannot be removed.
At some point they will actually start doing Gas emissions tests for diesels and opposed to the current joke of passing a light through the exhaust
fumes to see how much smoke there is.
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cliftyhanger
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| posted on 12/6/14 at 01:40 PM |
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I suspect that they will also soon start checking for remaps on cars. Not hard to do, just plug in the old OBD scanner and it will say if the map has
been modified......
That will cause a few people sleepless nights.
But we recently bought a vx diesel, ecoflex thingy. All good so far, but it gets plenty of decent runs up the motorway.
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MikeRJ
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| posted on 12/6/14 at 02:29 PM |
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quote:
Originally posted by JAMSTER
just have removed and have a remap
Hope you have a friendly MOT tester.
quote:
Originally posted by D Beddows
and in those 60 miles you just pumped most of the particulates the DPF had been protecting the planet from into the atmosphere anyway......
The captured particulates are burnt at high temperature which results in a cleaner exhaust than directly emitting diesel smoke. It would be a bit of
a pointless exercise if it just captured all the particulates and then let them all go again.
[Edited on 12/6/14 by MikeRJ]
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pewe
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| posted on 12/6/14 at 05:26 PM |
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"The captured particulates are burnt at high temperature which results in a cleaner exhaust than directly emitting diesel smoke. It would be a
bit of a pointless exercise if it just captured all the particulates and then let them all go again."
But isn't it a trade-off, MikeRJ ^^?
If I understand it correctly regenerating the DPF turns whatever's blocking it into CO2 and water rather than chucking out diesel particulates?
Both are harmful directly or indirectly to the environment and/or humanity so it seems to me it's a lose/lose situation regenerating it  not
that I'm complaining as we were able to (sefishly) continue our journey
BTW not wanting to rake over the coals but did you see the bike at the TT spontaneously combust when they were refilling it? Looked like the rider
suffered charred nuts and hands.....
Cheers, Pewe10
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britishtrident
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| posted on 12/6/14 at 08:35 PM |
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VW have had major problems with DPFs not regenerating on smaller engined cars, to the extent that the dealers were advised to steer buyers such as
district nurses and little old ladies likely to do stop-start or short journeys towards petrol models.
A major clamp down on re-maps is on the cards.
Following the lead of some US States checking petrols and diesels via the OBDII socket must be on the cards, for both MoT and roadside checks with
recent vehicles you can tell a lot from the I/M Readiness self tests.
See. http://www.autotap.com/techlibrary/obdii_and_emissions_testing.asp
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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mcerd1
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| posted on 13/6/14 at 07:40 AM |
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quote:
Originally posted by pewe
But isn't it a trade-off, MikeRJ ^^?
If I understand it correctly regenerating the DPF turns whatever's blocking it into CO2 and water rather than chucking out diesel particulates?
Both are harmful directly or indirectly to the environment and/or humanity so it seems to me it's a lose/lose situation regenerating it
The soot particles are proven to be a bigger / more immediate issue - they are known to cause breathing problems for the local population
so that wins hands down vs a small increase in the CO² output and its still less than the CO² from a similar output petrol (at least that's what
I was lead to believe)
the problem is that in reality they don't work that well
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cliftyhanger
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| posted on 13/6/14 at 08:51 AM |
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And to stir it up a bit, water is not exactly harmful. Unless you can't swim. CO2 doesn't do anything nasty except insulate the planet a
bit. And has anybody mentioned it is what plants "eat"
the real nasties are to sulphur and nitrogen compounds, taken out by cats on cars. And soot from diesels as mentioned above.
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