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Don't think I want one of those DPF things for Christmas.
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The extra diesel is needed to help burn the soot from the DPF. I think it's high temperature plus the fresh diesel that is used.
I've just realised that for a lot of my driving it's either 30mph or 70mph. In the Mazda6 143PS engine, 30mph is 1800rpm in third gear - this is not high enough for regen to occur. At 70mph in sixth gear it is also below 2000rpm.... hmmm.
I live about 2 miles away from a motorway so if I drive from home and then long distance on the motorways at 70mph the DPF might not regenerate anyway!
Quote from the AA site on DPF:
"We're seeing some evidence of these systems failing to regenerate too, even on cars used mainly on motorways. It seems that on cars with a very high sixth gear engine revs are too low to generate sufficient exhaust temperature. Occasional harder driving in lower gears should be sufficient to burn off the soot in such cases. "
But there's never been any indication of failing to regenerate on my car - not in 15500 miles. I just think it's injecting too much. Someone with this problem on technical had a faulty injector which was injecting too much diesel. I will ask about this on Tuesday when I get an oil change.
Rob
Edited by rtj70 on 21/12/2008 at 17:54
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while it is in the dealers ask them to do a regeneration and ask them to check if the ecu software is upto date
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I can ask but the cost would need approving.
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Rob, one thing I've been doing in the past 3 months or so is driving in a lower gear than I previously would have done, to keep the revs in the 2,000 - 2,500 rpm zone.
This means the engine is in the upper half of its peak torque range, which in turn should mean higher exhaust gas temps, and a better chance of passive (i.e. ongoing) regeneration.
I often find myself on single-carriageway A-roads in moving traffic at about 40 mph with no chance to overtake for 4 - 5 miles at a time. I try and use these occasions to regenerate by leaving the car in 3rd.
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IMHO, these things are not fit for purpose.
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I suspect if they are driven properly, there won't be a problem. We need to get over our aversion to allowing an engine to rev and to work.
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"I suspect if they are driven properly"
But someone needs to define "properly". As I say mine has never warned the DPF needs me to do anything to start regeneration so it must be doing it. But it is still putting too much diesel in the engine oil.
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>>But someone needs to define "properly"
Yes, I agree.
One of the underlying problems is that most motorists don't tend to push their engines anywhere near as hard as they are driven during testing and development, and this mollycoddling of engines doesn't really do the engines any good.
I've written before about the Ford research where they found that people tended to change up far too soon.
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The problem with the Mazda6 seems to be short journeys and stop-start type journeys. It's ironic that it seems if this is your sort of journey the original Mazda6 diesel with DPF is not suitable. At the other end of the Mazda range, the RX-8 is also not suitable for short journeys either.
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Short and stop start driving is bad news for any DPF diesel car.
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Such progress.
Disels should be ideal for stop start city type work (erm look at taxis maybe?). Now they have complicated it!
Good design, no doubt. Practical and sensible, no !
Fit for purpose? Interesting? Wonder if people are told this when considering purchase etc ?
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We have a Peugeot 106 diesel which has spent its entire 15 years doing 1 - 2 mile runs.And a Yaris diesel doing little more.
Both with no issues at all from the engine. Zip.
And moderne diesels cannot cope?
If I had one that behaved like that, I would want my money back as unfit for purpose.
POC.
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This is unbelievable!
I was whinging to my mechanic about how I couldn't fix my volvo V40 which is almost a right-off after 10 years, whereas anything that had gone wrong with my 25 year old 140 used to cost about £30 and could be DIYed.
So my wife borrowed a friend's mazda6 (which she wanted me to buy) and is now stuck 200 miles away on the M5 at 11:30pm with a baby on board with DPF problems.
This is not progress! this is lunacy! My tractor is 40 years old and there is nothing on it that you do not need to make it go! Certainly no computer. If it plays up, you hit it with a stilson.
I heard that the Apollo 11 got to the moon with less computing power than a mobile phone.
Its high time engineers designed cars to suit the people who drove them and stopped telling people they need to adapt to the rubbish cars that are produced, half the cost of which is 'value added' junk which starts going wrong as soon as you think you need it. The only winners now are the dealers!
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"Fit for purpose? Interesting? Wonder if people are told this when considering purchase etc ?"
I was not told this by Mazda or the lease company when I selected it. But I also do long motorway jouneys for which I want a big efficient car. So this effectively says I need two cars.
The lease company have only recently become aware of some of these problems on the Mazda6 with DPF. But I was not the only one getting one at the back end of 2007 - they were good on the monthly costs.
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>>Wonder if people are told this when considering purchase etc ?
I think that's the important question. If DPF isn't discussed during the sale, you might argue that car has been mis-sold.
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But not all DPFs work the same as the Mazda6 one. And the new 2.2l diesel from Mazda has a different DPF. It is said to regenerate twice as fast and needs doing half as often.
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The situation with DPFs is very similar to when cats were introduced in '92 / '93, there were a number of warranty issues and press horror stories about cat failures etc but it fairly quickly settled down.
I hope it's the same this time around, and resolves quickly.
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I've had loads of DPF problems in my Zafira. Eventually the DPF was replaced along with the EGR valve and ECU all under VX warranty.
I don't do short, stop/start journeys, but I do use 6th Gear quite a bit when on Motorways - namely to get the MPG up. Since the replacement I have now started to 'hang on' in a gear rather than change up and noticed that at the least the DPF in regenerating under its own steam (I just watch the instant fuel comsumption plumet!).
I've also moved away from SuperMarket Fuels and discovered that Shell gives me good performance and smooth running (not V-Power). Last fill was BP Ultimate and so will be the next few fills, just to see how that behaves in the Zaf.
Although I'd like another Zaf when it comes to 'trade-in' time, the DPF issue will be one of the deciding factors.
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My employer encourages use of supermarket fuel because it's cheaper! We all have fuel cards.
The problem with EuroV emissions is all diesels will have to have DPFs...
I have a feeling my next car will be a small capacity turbo petrol - had two before. And probably would have again but the choice did not include VAG cars the last two times.
I remember when colleagues grumbled when we all got taxed on emissions (they were not "aware") many years ago. I'd selected the Golf (1999) and Passat (2000) for these very reasons. Lower CO2 emissions and okay performance. Emissions of forced induction engines much better now too (diesels not so good back then IMO). More cars now coming out with turbo petrols it seems.
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One of the underlying problems is that most motorists don't tend to push their engines anywhere near as hard as they are driven during testing and development and this >>mollycoddling of engines doesn't really do the engines any good. I've written before about the Ford research where they found that people tended to change up far too soon.
It's up to the manufacturers to design engines that are suited to the motorists.
I don't like diesels of any kind and all this DPF nonsense just proves that the technology is being released on the unsuspecting public before it's sorted. I don't fancy being an unpaid development engineer for the manufacturers so it's petrol for me.
Edited by The Melting Snowman on 22/12/2008 at 21:14
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I suspect if they are driven properly there won't be a problem. We need to get over our aversion to allowing an engine to rev and to work.
When the standard rep-shed has 140-180bhp, and rarely needs more than 50 to move itself along, it's not going to do a lot of work. If buyers could accept engines were sized for the job in hand they'd be working nearer to capacity.
Driving round in third because the manufacturer can't make a car properly should be unnecessary.
Edited by Manatee on 22/12/2008 at 21:24
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>>> Driving round in third because the manufacturer can't make a car properly should be unnecessary <<<
I think it's more a case of we've all got used to modern engine management & injection systems, which enable engines to pull smoothly from tickover and lug high gears at 1300rpm .... while modern cars will do it, it's not mechanically sympathetic to make them do so.
If you tried doing the same in an older carburetted car it would pink, cough, spit back etc so you'd be forced to change down a gear or two ...
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I had an 895cc Polo with carburettor in 1979 that would pull smoothly from 20mph in top. I don't advocate labouring, I'd actually rather use the lower of two gears when on the cusp, to use lower torque. I'm driving round the potential fragility of the DPF as you are driving round the DPF.
The aforementioned Polo was abused mecilessly when I was a feckless youth (with a company car) and never missed a beat (give or take the odd knackered drive shaft)
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I've done 10's of thousand of miles in my Focus 1.6 TDCi with a DPF and never had any problems with the DPF.
As already mentioned when Euro V for cars comes into force next year a DPF is required to clean up the Particulate Matter (PM) that otherwise some person would breath into their lungs. Better for the PM to go into a DPF than someones lungs.
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But for EuroIV you didn't need a DPF.... my Mondeo was EuroIV without.
I suspect they are trying out DPF on EuroIV diesels so they work (for emissions) on EuroV. They seem not to work properly on EuroIV for some.
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Good point Mike.
They should make them properly, sans catalysing fuel additives and the requiremnt to keep driving for 20 minutes when a light comes on.
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Here's some more info, with a very detailed section specific to VAG cars equipped with DPFs. It has in-depth info about soot-loading thresholds, exhaust temps and more.
www.tdciforum.co.uk/viewtopic.php?t=4107&highlight...3
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Just read through the info - found it very illuminating. It seems that if my wife had a DPF diesel for her Home Care work it would become 95% blocked and need a new DPF within a few days.
Can you imagine - someone is trapped in a soiled bed - by age and infirmity - hungry and needing a bath. But the home care worker approaching in her car can`t stop because the DPF (having reached 95% due to her work demands) needs a further 15 minutes running above 40mph or its ruined. What are they supposed to do? head out of their work areas and cruise down a Motorway? Or exhausted after work, not come home but keep on driving...
I think if we had one, I would be tempted to take it off and `rod it out` using a broom handle or iron bar..
Yeah.. I know..but what a farce... ;)
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Fabulous link that... reading through that material has more or less convinced me never to buy a diesel fitted with a DPF. I'll stick with my old Octavia 1.9 non PD as long as I can. I was originally attracted to diesels for their simplicity and economy benefits over equivalent petrols in the 90s. eg the XUD 1.9 unit. This was a lovely sweet running engine, hardly anything to go wrong, 55mpg day in day out. The complexity and likelihood of failure of DPF and the even more demanding forthcoming Euro 5 and 6 requirements makes me shudder! I'm wondering if future diesel technology will actually be cost effective and workable for the average motorist within these EU requirements? Or perhaps we are just in a position where the technology is nearly-but not quite there yet and manufacturers will overcome these glitches and produce DPF technology with more robustness.
Are there any of the latest models on sale without DPF, meeting Euro 4 or 5?
Cheers and Happy New Year All!
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"Are there any of the latest models on sale without DPF, meeting Euro 4 or 5?"
Exactly what I`m thinking Bazza. My 2005 Punto van with the Multijet - met Euro 4 without a particulate filter and the older 2002 indirect injection job soldiers on..
In other words, re the older car - attempt another 5 years hoping technology will sort the problem? Or grab one of the last non DPF (if available) and try to get 12+ years out of that.
The irony is that a battery car (or light van - but not micro-car) with a twenty mile range and top speed of 40mph would be perfect for my wife`s car....
Edited by oilrag on 01/01/2009 at 11:11
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Or maybe a simple petrol small car? eg Yaris 1.0, Sirion 1.0, Aygo 1.0? All with the fantastic 3 cylinder unit that averages somewhere in the 50s mpg, not much to go wrong either. Or Panda 1.1? I think I'd be thinking if diesel was really worth it?
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Its really exceptional cold running stop start use though.
Its getting 53mpg on 30 or so few hundred yard runs a day. In today`s weather at around -1c , the engine temperature gauge will never register on the scale all day. Its like that all winter and never reaches operating temperature.
She had a Seicento 900cc petrol for a few weeks before buying the diesel and it was costing around double for fuel. It ran on fuel enrichment the whole time.
Under more normal short journey conditions, I think the balance may well swing to petrol and I don`t think I will be replacing the van with another diesel.
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In which case, if I were in your shoes, I'd keep it. A 2002 vehicle isn't old, with regular oil changes and a weekly blast to blow out the cobwebs, warm everything up to boil off condensation and charge the battery, it will last for years. Any diesel you buy now will inevitably be more complex, and I can't see would offer anything over what you already have. The trend seems to be that DPF is very unsuited to that type of use - amazing really, how EU legislation can ruin such a wonderful concept.
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Yes, It`s likely we will keep it. It`s been serviced only by me - half interval oil & filters and grease covered subframes... ;)
I really am amazed by the DPF situation and eveything around it - such as piston scraper rings taking derv off the cylinder walls into the sump..(how could they not anticipate that?) It almost seems as though the cars currently on the road are `test beds` for the technology..
Edited by oilrag on 01/01/2009 at 12:10
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And i would really check out a new petrol for your good lady's particular running Oily, maybe by trying one on her particular work before committing to buy.
Trying to teach me grandma probably..;)
The reason i say this is we hear of the excellent fuel consumptions of the 3 cyl petrol fitted to the C1/107/aygo and apparently one or two more, and i have no reason to doubt those figures.
And i actually like driving those cars (hide this post someone) as they have a marked difference to most new cars in that they do have a remarkable amount of torque at very low revs, and are reluctant to stall, the same cannot be said for many others.
However as you know with my job i am using the very low down lugging power of engine's to get them onto the truck during loading operations.
Now many modern cars including most modern diesels don't have that ultra low speed torque to enable easy loading and its a case of higher revs and clutch slipping often, cruel but no choice.
The little engine we are talking about doesn't behave like that and will happily chug down to stall speed and still pull up the slope without complaint.
Thats great, but i do often see black smoke from the exhaust during that exercise, which i believe is a very competent fuel enriching device operating as an anti stall, the way our good old fashioned diesels would perform.
I can't think of any other reason for black smoke, and i'm not mistaken on this.
What i do wonder therefore as the Lady Oilrag will be driving in a similar manner to me during the course of the good work (and long may she continue to do so) with a cold engine will she be involuntarily bringing this (possibly i'm totally wrong, it won't be the first or last time) enriching action into use, with i wonder what effect on consumption.
The vast majority of users may never notice this as i have, as how many people try to reverse a stone cold engine up a 1 in 3 or so slope.
I do go on a bit, hope you can make head or tail out of my waffle..;)
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"driving in a similar manner to me during the course of the good work (and long may she continue to do so) with a cold engine"
I think so GB. She had a 900cc Seicento for years when working in a nursing home - prior to community work. That involved a four mile run to work and of course the same back. Fuel consumption then doubled on the home care work and after 2 weeks of that we bought the diesel. as you will know, its the old Lucas (fingers crossed;) rotary pump and indirect injection.
The diesels consumption - year in year out - over the last 6.5 years has been 53mpg working and around 60mpg on a steady run to the coast. Only 7mpg difference between the worst running conditions and the best. The Seicento petrol was around 25mpg difference. ( approx 50%)
Incidentally, we tried a Grande Punto petrol for a few days last year and it was doing 28mpg
Typical work use is up to two minutes running (often 30 seconds) - twenty or 30 minutes standing. Its now done 50,000 virtually exclusively in that use - runs like new.
I don`t think the current small petrol engines are suitable, for this extreme use - neither are the new DPF diesels.
Amazing isn`t it? As said, we really need a battery car that can be charged over night.
Edited by oilrag on 02/01/2009 at 07:41
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Its now done 50 000 virtually exclusively in that use - runslike new.
I think thats proof enough if any were needed of our oft ridiculed high maintenance regime. Standing by for incoming..;)
HJ referred to the lowering of emissions even further in that fine little Toyota engine, i hope they don't manage to lose that wonderful almost stall speed tractability in the process, which in my humble makes it stand out above many others.
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