2006+ Honda Civic Forum banner
1 - 20 of 33 Posts

·
Registered
Joined
·
303 Posts
Discussion Starter · #1 ·
Hi there guys, as you know DPF is a common issue with most diesels, it appears to be more VAG cars but you all have them. I wrote an article on these the other week for our blog/help page BHPplus but thought you may find it useful, rather thank linking it I figured it would be better for you re-posting it for you here (even though Google wont like it), I hope it helps at least a bit, there was a decent amount of research before I wrote it. :popcorn:

Cheers guys

Particulate Filters (DPF) the thorn in the diesel driver’s side.

Small city commuting car's with the torque and economy of a diesel engine seems like the perfect match and many people have started to realise this. SMMT shows diesel models are accounting for 50% of the overall new car market. The trouble is to meet the strict 2009 Euro 5 emissions guidelines which all car manufacturers must adhere to lowering the harmful gas output from vehicle exhausts.

Among these gasses is Particulate Matter, small molecules of solid or liquid matter suspended in the atmosphere. These can be seen on older diesels as the black foggy cloud of soot that comes from the exhaust under heavy acceleration.

To meet the Euro 5 regulations all new diesel cars are now fitted with a Diesel Particulate Filter (DPF). These filters are a very effective way of removing this particulate matter and can be as much as 85-100% more effective. The DPF filter collects all of the particulate matter, much like a filter would collect dust in your vacuum cleaner. This runs in cycles and when it becomes full needs “emptying”, known as DPF regeneration – this is done by burning off the soot at high temperatures.

There are two forms of regeneration:

Passive, done at constant speed over 50mph
Active, the ECU increases the fuel entering the engine in order to heat up the exhaust gasses
Active regeneration is more common in cars where the filter does not get as hot, cars with a smaller engine or cars that have the filter further from the engine because of space. Some smaller diesel engines also have a fuel additive in a small tank which is added automatically during the regeneration as the engines do not get hot enough.

So how does this affect you?

Not clearing your filter can cause the soot to build up over 75% and after this the filter cannot be cleared via the standard cyclic regeneration. If caught quickly a dealer can induce forced regeneration costing around £200, but as with the fuel additive based engines, this can leave a residue which slowly builds up meaning in these cases the filter has a limited life.

In the long term, if the filter is left too long without clearing, or the residue builds up too much, the filter will need replacing which can cost upward of £1000. Overloading the filter, ignoring warning lights and not seeing a dealer when the error does not clear can completely overload the filter causing excessive back pressure and may lead to irreparably damaging the engine. This could mean paying out even bigger bills in the multiple thousands, to top it off most manufacturers will not cover DPF issues under warranty.

The popular Nissan Qashqai, which has 3 different diesel engines, offers an 18 page thread with 627 replies on DPF issues on the popular Qashqaiclub.co.uk, ranging from members not being told about the DPF when buying the car, to the light coming on signifying a required regeneration after only 3k miles of ownership. In extreme circumstances, taking an extra journey every 2 weeks in order to cycle the filter is the only suitable solution.

But don’t give up hope, this is where you come in!

The first port of call is to refer to your vehicle handbook, as many vehicles will have varying instructions to maximising DPF efficiency and life.

When a filter reaches its pre-set limit, usually around 50%, a light will come on on the dash which indicates the filter should be cleared as soon as possible. To do this generally will involve an un-interrupted 20 minute drive at 40-50mph above 2k rpm; this varies between manufacturers as Nissan ask for above 50mph for 30mins. Because of this, a road where you must slow down for a roundabout will not complete the cycle.

Cars where there is a fuel additive will have a small tank for the additive, very little of this is used and it is topped up during the usual service schedule, this must be completed as without the additive the filter may not be possible to regenerate.

Some cars will suffer from these issues more than others; cars that are used predominantly for town trips will not clear the filter during normal driving. Similarly, small engine diesels which frequently do not get hot enough alongside cars with a very economical top gear keeping the revs extremely low will not reach the right temperature when on the motorway. These may require an extra trip in a lower gear just to clear the filter, whereas some diesel drivers who use the motorway regularly may never see the light or have to clear the filter.

It was a common thought that Tuning boxes used to cause harm to the DPF, the poor tune of some boxes and resistor based tuning boxes did, due to the generic extra load on the endgine would create increased soot and clog up the filter much faster. However the latest Speedhawk boxes do not suffer with the same issue, as they are mapped for the engine specifically, so do not increase soot output as they are optimised. The boxes are actually if anything good for the DPF, especially with smaller engines as the increased boost pressure and performance means the DPF should be easier to clean, which makes the correct cycling temperatures also easier to reach.

There is a wealth of information available on DPF filters at your local forum, but in summary, following your hand book instructions and never ignoring a warning light will save you a lot of money. If you are in the market for a new car and don’t get out on the motorway much, make sure you take into account DPF cycling before you take the plunge.
 

·
#MrGrumpy
Joined
·
13,117 Posts

·
#MrGrumpy
Joined
·
13,117 Posts
Really? That's awesome! Clearly this is the diesel to get then! How do they manage that with the Euro regs any ideas?
It's UK specific for the 8G Civic so I'd guess they introduced the model just before it was compulsory.
If you buy the European version it's got a DPF, and you could request one from the manufacturer as an optional extra if you wanted it on the UK version - although why you'd do that I have no idea!!
 

·
Registered
Joined
·
303 Posts
Discussion Starter · #6 ·
It's UK specific for the 8G Civic so I'd guess they introduced the model just before it was compulsory.
If you buy the European version it's got a DPF, and you could request one from the manufacturer as an optional extra if you wanted it on the UK version - although why you'd do that I have no idea!!
Maybe because they like reading my articles and enjoy the drama of it :facepalm:
 

·
#MrGrumpy
Joined
·
13,117 Posts

·
Arfurs right hand man
Joined
·
4,125 Posts
And Honda's that DO have them fitted don't have them fitted at the cold end of the system but in a cartidge at the manifold end, i.e. they are nearer the hotter end of the system and therefore the regen cycle kicks in much more frequently leading to alot less foul ups due to doing 20 years of 3 mile a day journeys.
 

·
Premium Member
Joined
·
15,644 Posts
I have a DPF on my Octavia vRS and its fine...Regenerates when you go on a motorway run and no smoke or soot from the exhaust
VAG PD engines can have a problem with them clogging..but the newer CR engine does not...They seemed to have solved that...I hope Honda have that sused as well on their CR diesel!
 

·
Living the dream!
Joined
·
8,545 Posts
We had a Auris T180 (2.2 180bhp td) and in emissions it was years ahead of its time but unfortunately it had a 5th injector in the dpf to do burns. Long story short once my wife started working local (5mile drive to work) it killed the MPG low 40s to mid to late 20s, we had this back to Toyota and nothing was found wrong (car even went back to the factory). In the end I drove to Swindon at a steady 70mph for 3 hours and only got 32mpg yet the CRZ did 49mpg on the return trip.

Would I ever buy a diesel again? in short no because with the extra cost of buying a diesel and then the extra cost of a diesel and to be honest not a massive MPG difference as people like to think its just not worth it for us and truth be known a FN2 is as economical as the T180 was in the end and a lot better car to drive.
 

·
Premium Member
Joined
·
15,644 Posts
My Mrs had DPF issues with her CR diesel engined A3 (2010) until a software update, so wouldn't be quite so confident! :lol:
Very few issues reported in the Forum..unlike PD Diesels
I can only go on that information..I didnt say it was unheard of, but compared to the PD, they have more reliability
I still think however, like others, that they are a nuisance and a potentail worry, particularly for high milage users..at least they appear to be more reliable than they used to be..so some progress has been made. Politics eh!! Global warming? Phaaa...more politics!! But thats another story..LOL
 

·
#MrGrumpy
Joined
·
13,117 Posts
Understandable, and the issue we faced could well have been isolated.

In any case it's put me in the position where I won't buy a diesel with a DPF again!
 

·
Premium Member
Joined
·
1,677 Posts
Would I ever buy a diesel again? in short no because with the extra cost of buying a diesel and then the extra cost of a diesel and to be honest not a massive MPG difference as people like to think its just not worth it for us and truth be known a FN2 is as economical as the T180 was in the end and a lot better car to drive.
Had to chuckle at this. So if you want an economical diesel - buy an FN2 instead!
 

·
Living the dream!
Joined
·
8,545 Posts
Would I ever buy a diesel again? in short no because with the extra cost of buying a diesel and then the extra cost of a diesel and to be honest not a massive MPG difference as people like to think its just not worth it for us and truth be known a FN2 is as economical as the T180 was in the end and a lot better car to drive.
Had to chuckle at this. So if you want an economical diesel - buy an FN2 instead!
Well in short in my experience if you want a diesel with power which has a DPF fitted there was not really much mpg difference and lets all remember diesel has been and can be up to 10ppl more which also eats into the mpg advantage. The best we ever got from the T180 was 46mpg driving like a 80 year old on his way to church over 400miles (long runs) yet Ian (H7LFW) got 46mpg coming home from Scarborough the other week doing a steady 56mph on cruise control in a FN2. Now the CRZ lacked the outright power of the T180 but was quicker 0-60 and was a better drivers car due to weight etc and loads more economical (we averaged 48mpg over 9000miles) and me personally would love to see a 1.6turbo CTR with a decent 30BHP electric (hybrid) motor.
 

·
Premium Member
Joined
·
131 Posts
I am also far away from the official MPG figures. Yes, i drive spirited, but anything below 6.5 L/100 km is outright impossible. Mostly i am around 7L/100 km. A DPF regeneration alone hurts MPG by about 0.2 L/100 km according to the display, i guess the additional backpressure of the DPF would also cause some MPG loss.

Add the extra miles to drive to avoid interrupting the regeneration (possibly bad for turbo, as post-turbine temperatures reach over 500°C!), and you can almost drive a petrol for the same cost.

Considering all the things that could fail in a modern DPF equipped diesel, a petrol could really be more economical.
 
1 - 20 of 33 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top