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Why is it that, whenever I see a smokey exhaust, it seems to be part of a Ford Diesel?? Either a Mondeo or a Focus.
Are they more susceptible to it or something?
Rachel
Plenty of other smokey diesels on the road. Most of the ones I've noticed lately have been VAGs though.
Not just Fords ime, seeing almost new cars puff out black smoke at every gear change means I'd never buy a diesel - too dirty.
Could be a million different things from a leaky gasket to a stuck EGR valve. The main reason is the driver. Mondeo owners are in middle age denial and Focus drivers like to make everyone think they've got an ST. As a result they both have bricks over the gas pedal.
Me, I've got a diesel Vectra which I drive like a massey ferguson.
The guy who was in a rush to pull out of a side road before I got there resulting in the saving of a couple of seconds on his journey and giving me a nice lung full of whatever crap he was throwing out, would disagree with the Ford thing, he was in a Rover.
Not just Fords ime, seeing almost new cars puff out black smoke at every gear change means I'd never buy a diesel - too dirty.
You do realise that the exhaust is on the outside of the car don't you?
I do.
I'd never buy a diesel - too dirty.
Of course, visible emissions are far "dirtier" than invisible ones.
And I have a Massey Ferguson...
Most diesels are smokey, which is why it pi553s me off that my 'clean' petrol is way more expensive in tax
Low revs letting carbon build up in the system. Put your foot down and that frees the build up. Mine used to smoke badly when I put my foot up after a week of inner city driving
My Mondeo smokes terribly - had it since 3k miles & queeried it with garage but apparently nothing wrong - the upside is I can give tailgaters a lung full should they get too close 8)
Most diesels are smokey, which is why it pi553s me off that my 'clean' petrol is way more expensive in tax
Thankfully "boffins" can measure this invisible stuff and tax appropriately.
Junkyard - MemberThankfully "boffins" can measure this invisible stuff and tax appropriately.
Well. It all goes off CO2 doesn't it? Which isn't a good measure of pollution.
That said, anyone who thinks diesels are dirtier than petrol, just because of the almost completely harmless soot, is a fool.
Mine smokes like a chimney, especially when I put my foot down at 65.... Mph.
However my car has done 159k miles!
I discovered today that mine smokes quite dramatically when I try to pull out of a junction in the wrong gear. :/
+1 for the reliability of diesels though, 164k and counting!
I have a Mondeo and when I bought it it smoked big time. Now it doesn't so much as I make sure I drive it hard every so often. Even on the motorway at 80 your only doing 2000 rpm so doesn't really get the soot out.
We also have a newer VAG diesel. On start up that always chucks out loads of soot, but doesn't kick out as much as the Mondeo in normal driving.
Older Fords both diesel and petrol do smoke a lot but that's grey smoke from oil being burned - I don't know enough about Fords to tell you why it's characteristic but it's either down to worn valve guides or worn piston rings.
Older diesels like the 2007 Passat PD I've just handed back, smoke a lot on acceleration; a brown smoke of unburned hydrocarbons. Any fuel burned at too low a temperature or not fully burned will produce smoke as any stove owner knows. The new Passat I've just collected with the new common-rail diesel doesn't seem to smoke at all, no matter how hard I try.
We used to have a 1986 Land Rover diesel, which had a very primitive fuel delivery system. If somebody was driving up your chuff you could declutch and floor the throttle to rev the balls off the engine and a massive cloud of greasy black smoke used to come out, which usually made people back off smartish. Not that tailgaters bothered us because when Mrs Gti got rear-ended by a Freelander it merely squashed our spare wheel carrier while the Freelander was absolutely flattened.
Remaps... the little plug in boxes that boost diesel power just dump more fuel in when you put your foot down, hence possible smokey cars...
Had VAG cars for the last 6 years now and none have kicked out black smoke, the Pugs did mind.
Slightly off topic - what makes diesels so much more economical?
Diesel has a higher energy density than gasoline - so you need less fuel to get an equivalent amount of 'bang'. The trick though is to get all the energy out of that fuel, which is why it has taken until reasonably recently for diesel engines to fully meet the performance (in terms of drivability, smoothness and power) of gasoline engines.
What's gasoline? Must be a pain going all the way to the US to fill up....
Sorry - it's the term we use for petrol at work....don't know why really - obviously become a bit institutionalised! (trust a bloody engineering company to use a name different to 99% of the country....)
it's less down to the difference in energy density, and much more down to the operating temperature.
the efficiency of any heat engine is determined by the temperature drop over which the heat cycle can be run, in thermodynamic terms. for your internal combustion engine this is the temperature difference between cylinder temps and the ambient background.
diesels can operate hotter than petrol engines, since they don't pre-detonate like petrols do at high operating temps (pinking, iirc). bigger temp drop for the heat cycle means better inherent efficiency.
Slightly off topic - what makes diesels so much more economical?
To make it simple, Diesel cars are more efficient, basically every £1.00 of fuel put into a Petrol about 30% goes to making the car go forward the rest is lost in heat. Every £1.00 put into a Diesel about 45% goes to making the car go forward, so less is lost to heat.... hence why Diesels take longer to warm up on colder days!!
I have a nissan diesel and i have no black smoke issues.
Me, I've got a diesel Vectra which I drive like a massey ferguson
Having had a diesel Vectra, I can confirm they have more than just this in common with a tractor.
What's gasoline? Must be a pain going all the way to the US to fill up....
Odly, with the exception of the british public, does anyone refer to it as petrol? Even industrialy it's refered to as gasoline.
diesels can operate hotter than petrol engines, since they don't pre-detonate like petrols do at high operating temps (pinking, iirc). bigger temp drop for the heat cycle means better inherent efficiency
I think you have this the wrong way round? Diesel engines run about 200C lower than petrol engines but operate at higher compression ratios & are therfore able to convert more energy into forward motion, plus diesel whilst having the same calorific value of petrol (per kg) is about 15% denser, so more bang per litre of fuel.
Another factor that makes diesels more efficient is direct injection. You only need to inject the fuel you need to burn, whereas in a petrol you have to fill the cylinder with air/fuel mix so that it ignites - then if this is too much power you have to throttle it back which wastes energy.
As for the smoke - it's only bad when people tootle around town all the time. My diesels have always had lots of long trips and done some work, which cleans out any crud regularly. The Passat has never run so smoothly and cleanly as when I was in Germany doing lots of Autobahn.
My 1.9 Ibiza 105bhp wouldn't smoke at all no matter what I tried; the Passat can do a bit if I do lots of town driving then floor it suddenly. Globalti's Passat will have a DPF so no smoke.
I've got a 7 year old BMW 320d (no I'm not a sales rep!) and notice it smokes when I accelerate hard. Not loads but if the car behind has headlights on you can see it sometimes. I just assumed this was a combination of 'clearing it out' and burning more fuel.
So while we're talking about diesel, why is it more expensive than petrol now? I seem to recall years ago it was a good amount cheaper than petrol, is this because more people are driving diesels so 'they' have decided they can wangle more money from us or does it really cost more to produce (or is now taxed higher)?
I thought I read somewhere once that diesel is a by product of the refining process. If that's true (doubtful since I can't remember where I read it) why is it more expensive now?
[b]Smoking[/b] - largely down to the driver IMO. Mine smokes occasionally if you open the throttle sudenly. As someone posted above, diesels need to be worked hard from time to time to clear the soots out. It also helps to add some Redex diesel to the tank once in a while
[b]Gasoline[/b] - as much as I dislike Americanisims, "petrol" is a misnomer used by the British public. Petrol is short for petroleum, which covers a whole range of petroleum products. Gasoline is a blended fuel comprising a variety of different light hydrocarbon fractions from C5 to about C10.... and of course one of those blend components, C8, Octane gives it's name to the old octane rating
[b]Cleanliness and efficiency[/b] - It took me a long time to get a diesel, and it was a purely fiscal choice. As someone who works in the environmental industry I remain sceptical about the benefits of diesel over petrol. Tax and profits are a significant factor as far as I see it
There is always a light haze that you can see at night in the car behind's headlights.. I woudln't call this smoke really.
Petrol is short for petroleum
Have to pull you up on that one I'm afraid. Petrol is short for petroleum spirit ie something distilled from petroleum, which is not an unreasonable name. Next time you are at a garage look around you'll see some warning signs somewhere that say 'danger, petroleum spirit' or similar.
Diesel is worse for some pollution (NOx and particulates) and better for others (CO2 and hydrocarbons, both greenhouse gasses). So it depends which you consider important. If I lived in Athens I would not drive one because NOx and sunlight create smog, which is a terrible local problem there.
This is why petrol hybrids were invented, really - for the US market. The fuel economy of a diesel but with far less tailpipe pollution. And before anyone starts banging on about batteries being terrible things, find some real actual data about it. I'd love to see some.
Most diesel smoke is down to poor servicing. Diesels require a good, clean flow of air. If the air filter is blocked up, leak in the turbo charger/pipework or blockage i.e. EGR then it will overfuel creating unburnt diesel in the exhaust and smoke.
Diesel isn't a clean fuel like petrol and injectors and pumps can collect sediment causing poor injector spray and weak combustion so the fuel system needs regular, at least annually, to maintian efficiency. Products like Redex are useless on diesel fuel systems and need stronger products such as BG44 or Forte.
I'll look up BG44 and Forte, thanks. Definitely interested in keeping my diesel running nice and cleanly.
EDIT just looked at BG244, the first thing it says it helps with is 'hesitation and flat spots'. Well I'm seeing hesistation a couple of times every time I drive off, so I'll give it a whirl. Do you have to order it online?
Have run nothing but diesels for a few years now in our house.
Yes they smoke a bit when you boot it. It's just clearing out all the soot that's built up in your exhaust as you've been pottering along for a bit.
Top tip immediately pre MOT, give it a good thrashing (eg red-line it up a big hill in second) to get everything out of the exhaust system before. 🙂
This is what I was trying to describe and is just what I see, although not always.There is always a light haze that you can see at night in the car behind's headlights..
I'm amazed nobody has picked up on the use of the word 'tailpipe' already so here goes....
Tailpipe? TAILPIPE? It's called an [i][u]exhaust pipe[/u][/i] over here you know. 😛
The usual reason for black smoke is the engine running too rich, i.e. not enough air to burn all the fuel going through. It can be down to problems with the engine, but you can make almost any diesel do it by labouring the engine. Putting your foot down pumps more fuel through, if you're in the right gear for the speed you're doing, no problem, if the gear's too high the engine will pump out black smoke until the revs catch up enough to send through enough air to burn all the fuel. Electronic engine management helps, but can't always compensate for a heavy right foot.
The modern ones shouldn't do it if they have a fap (or particulate filter) as this is ment to trap the particules but its basically unburnt fuel. I can just about get my auto diesel to do it by giving it a real boot full but its only mild compared to others. Most manual diesel will do it noticable when floored or as above if they have ablocked air filter or spilt turbo pipe and the air/fuel mixture is rich.
oh and fi the fap filters are why the paris dakar trucks no longer smoke when they are racing.
Petrol is short for petroleum spirit
True - it's been a while since I've seen that in full!!
In my line of work it's always gasoline. To my embarassment I've even called it gasoline when paying 😳
Products like Redex are useless on diesel fuel systems
I do use the diesel specific Redex
That said, anyone who thinks diesels are dirtier than petrol, just because of the almost completely harmless soot, is a fool.
That's true. It's the emission of PM2.5 and NOx that we should worry about.
Twigged on last week why my windscreen was difficult to see out of at night. There was a film of oily, sooty, shit over the inside, which left me worried about how much has gone down my throat.
I have a diesel, but it has a particulate filter so I drive around guilt free. I reckon the vast source of diesel soot is coming from buses, which with their start-stop route and driver's tendency to boot it every time chucks out vast quantities of black smoke.
Busses have had DPFs for years I think. The new ones are very clean.
no problem, if the gear's too high the engine will pump out black smoke until the revs catch up enough to send through enough air to burn all the fuel
It's because the turbo is not spooled up. I think modern cars over-fuel a little bit to get the turbo spooled up faster when you boot it from low revs.. hence the little puff.
Petrol emissions are worse for the planet and diesel for people, tasty NOx. Mine smokes like a trooper if I've got my foot down, foot down off-boost and a I can produce a James Bondesque smokescreen which is great for deterring tailgaters.
TAILPIPE? It's called an exhaust pipe over here you know
Odly, I'd say the tailpipe is the bit after any equipment on a plant so its a prefectly good decription for the last few feet of the pipe form the silencer?
Top tip immediately pre MOT, give it a good thrashing (eg red-line it up a big hill in second) to get everything out of the exhaust system before.
We had an old fiat JTD that got through about 3 MOT's like that, so it definately works (and before TJ says theres no proof it wouldnt have passed anyway, it didn't, the garage tested it and told us to take it for a run after it failed the first time :P)
molgrips - Member
I'll look up BG44 and Forte, thanks. Definitely interested in keeping my diesel running nice and cleanly.EDIT just looked at BG244, the first thing it says it helps with is 'hesitation and flat spots'. Well I'm seeing hesistation a couple of times every time I drive off, so I'll give it a whirl. Do you have to order it online?
Make sure you buy the correct version BG244 for Diesel and [url= http://www.powerenhancer.co.uk/product.php/3/bg-244-diesel-fuel-cleaner ]Powerenhancer[/url] are the importers for it.
Products like Redex are useless on diesel fuel systemsI do use the diesel specific Redex
You're wasting your money try something like Millers diesel power sport 4 which will work out cheaper per tank and do a better job but putting a can of BG244 in your tank once a year will clean the system better and work out a lot cheaper over the same time period.
You're wasting your money
Although it does seem to work on the smokiness issue....
Will try to find some of that BG244, so cheers for the tip
My diesel doesn't smoke. It totally rocks. It is cool. People stop me in the street to tell me how cool and attractive I look and ask me about my obvious length and girth.
Honestly.
(He says, trying to convince himself that 'dad-car' is better than the TT that is now history).
🙁
My beemer does it on heavy acceleration when I change gear. It does have a sick thermostat at the mo though
Nothing wrong with the right type of Dad car m_f .. I have fully come round to the plus points of ours 🙂
molgrips - Member
Another factor that makes diesels more efficient is direct injection. You only need to inject the fuel you need to burn, whereas in a petrol you have to fill the cylinder with air/fuel mix so that it ignites - then if this is too much power you have to throttle it back which wastes energy.
Not necessarily. A modern petrol that uses stratified direct injection uses a wide open throttle and a weak mixture through most of the cylinder apart from near the spark plug.
Nothing wrong with the right type of Dad car m_f .. I have fully come round to the plus points of ours
Not feeling that love yet.
My wife did say 'it's very posh inside'.
So what, I don't want posh. I want a fun car.
🙁
Modern disels and particle filter and some (like some mercs) have urea injection to reduce NO2 - even to the point that they are suitable for strict US nox laws.
Not necessarily. A modern petrol that uses stratified direct injection uses a wide open throttle and a weak mixture through most of the cylinder apart from near the spark plug.
That was the second part of my post that I forgot to add 🙂 VW's FSI and TSI engines are fine examples 🙂
MF - you have to choices - either learn to love the plus points of your new car aka look on the bright side, or save up more money and buy another TT.
Modern disels and particle filter and some (like some mercs) have urea injection to reduce NO2 - even to the point that they are suitable for strict US nox laws.
Only the US versions have the NOx catalyst I think.
Once stricter NOx legislation comes to Europe (Euro 6), the NOx will fall dramatically from current levels and if an SCR (urea) system is used for this then there should be a corresponding drop in soot (and increase in fuel efficiency) as you can greatly reduce the amount of EGR required. Pop a DPF on (current diesels with DPFs are generally well below legislated soot limits) and you have a very, very clean engine.
Nice.. so I should hold off buying a new diesel til.. when? 🙂
owenfackrell - Memberfap filters
I don't say this very often, but on this occasion I will- LOL.
You can get the NOX catalyst mercs in the UK (Ad-blue), but not many are fitted since there is no tax incentive.
Euro 6 comes into force in 2014, so you will probably start to see Euro 6 compliant vehicles at the very back end of 2012 and into 2013. NOx emissions are almost a third of Euro 5 and although particulate mass doesn't change, there is new legislation for the number of soot particles over a certain size (the harmful, smoke making ones) so visible smoke will be reduced again.
Particulate filters have to regenerate every so often that chucks out loads of soot.
Only problem with DPF's and whatever they bring out to comply with Euro 6 is that they are trapping rather than eliminating the problems which just causes more problem as anyone with a DPF fitted will know that clog up causing running problems.
Probably easier to just buy a small petrol car then?....seems like diesels are getting ever more complicated and are likely to be ludicrously expensive to fix when they go wrong.
I was in Alderley Edge today and there was so much smoke i thought there was a fire but it was some guy revving his Ferrari 430 ( may be it had a ford desiel engine in it),
Only problem with DPF's and whatever they bring out to comply with Euro 6 is that they are trapping rather than eliminating the problems
Where do you think it goes after being trapped? The burn-off cycle actually burns it into CO2.
I know a few people with Skoda and VW's who would disagree due to the amount of DPF problems they have had.
It does. Whether or not it works properly in any given car is another issue.
Seems to me like most people who have DPF problems are ignoring the advice about how to look after them.
I have a 100k 04 reg Mondeo and the amount of soot it produces varies wildly during the period between services (much less sooty with clean oil in and new filters) My money is on that being due to it being well maintained and driven mainly on the motorway for decent distances.
It's nowhere near as bad as some (newer) cars we've had in the house (both VAG diesels in lighter cars).
I suspect the worst "smokers" and some of the DPF failures are those used mostly round town and which never get taken over 2000rpm and that never get a good hot exhaust system to stop them getting all sooty OR those that don't get good quality clean oil and filters on a regular basis.
As for the cleanliness / tax issue there's good and bad in both fuels environmentally. At the moment it's politically expedient (and administratively more cost effective) to focus on CO2 so guess what that's how your VED is calculated. Diesel drivers pay more at the pump in tax (but my money's on that being demand driven rather than truly environmental).
Given a choice I prefer petrol to drive but diesel has certain economic advantages when you do bigger miles for work!
As an exhaust system designer of more than 20 years I want to point out that Molgrips has it right. A DPF does not allow particles through - no matter what the operating conditions are. The re-generation (increasing exhaust gas temperature to oxidise the soot into CO2) is triggered by the engine control module and is a result of the diferential pressure between DPF inlet and outlet reaching a set threshold level - The duty cycle of the vehicle is completely irrelevant.
In short if you don't maintain a diesel correctly it pollutes just as badly as a poorly maintained petrol - Black smoke = poor maintenance
MF - you have to choices - either learn to love the plus points of your new car aka look on the bright side, or save up more money and buy another TT.
Saving up to buy a house with a garage to store the Elise I want in... 🙂
The duty cycle of the vehicle is completely irrelevant
Really? I was under the impression that if you did enough short trips even the regen cycle wouldn't work and you'd have to take it to a garage..?
The regen cycle cannot occur if the vehicle never enters a driving mode that support the regen cycle (e.g 10 minutes steady state at normal engine operating temps) - So you are right. The fix is to spend a few minutes on a dual carriageway - much cheaper than a trip to the garage where some unscrupulous person may convince you part with some of your hard earned
I know that some site vehicles like fork lifts and dumpers have a DPF that has cartridges that are removed each night and cleaned off. A DPF on a car that could be removed and cleaned out this way would be pretty handy for people who do short trips obliviously and then have to limp to a garage. £30 instead of £800.
On the honda accord forum there are a couple of threads about taking off DPFs and cleaning them with a high pressure washer. It seems to work. I just made sure my diesel didn't have one when I bought it and keep it well maintained so it doesn't smoke.
Problems DPF's, EGR's, turbo's etc... the savings on fuel petrol vs diesel can soon disappear.
On the Accord forum the "common faults" for petrol has 169 replies at the moment and diesel has 3360 replies!!
Remember diesels generally do more miles and there are more of them around.
The guy who said buy a small petrol basically has it right, by euro6 I should any small to mid cars will generally be petrol. The diesels will be hugely expensive, not good on a light duty cycle and plenty complicated.
Problems DPF's, EGR's, turbo's etc... the savings on fuel petrol vs diesel can soon disappear.
Only if you get the problems. I've just done almost 40k trouble free miles. Oh, tell a lie, I had a fault with the airbag wiring the other day.
40k miles cost maybe £4,100 if you assume an average of £1.20/l over the last two ish years. A petrol would have cost maybe £5,300 at 38mpg (a guess for a petrol Passat) and £1.15/l
You are absolutely right - with no problems you are going to save a lot of money on fuel petrol vs diesel. I ran a citroen ZX TD for over 100K with not a single problem and 40k on my current merc without a problem. The issue is that it's more of a risk now with how complex modern diesels can be. If they go wrong you can have some big bills that soon cancel out fuel savings.
My mondeo doesn't produce soot and it is more than worn in now, probably because it's rarely running at low enough revs to collect.
Another example;
Of the Land Rovers at work the TD5's are smokier than the new TDCi, not so much because of the common-rail technology progression or age, but the the heater tecnology progression, the older ones spend a lot more time idleing to get the cab at least as warm as outside, whilst the newer TDCi is warm before we get to the road, straight from start-up.
the older ones spend a lot more time idleing to get the cab at least as warm as outside
That's a bad idea. Just MTFU and drive the thing, it's better for the engine and will warm up far quicker. Your newer car will have an electric heater in it.