Peugeot306tld - A pearce
I have a pug306tld which has done 80000 miles. It emits black smoke on pulling away. IT runs and starts perfectly. Could anyone please advise how to cure this and is it easy.
Re: Peugeot306tld - David Woollard
If you are using a quality diesel then think of an "in-tank" injector cleaner, some think these are good others not. Can't do any harm.

Next step at this mileage is an exchange set of injectors, or an overhaul of yours.

After that you could be looking at a pump/timing fault.


Re: Peugeot306tld - Alan
There is hardly a diesel that does not smoke (badly) when it pulls away accelerates or climbs a hill. That goes for brand new ones as well. Its time the manufacturers admitted the fact and stopped pretending that they are low on emmisions. I followed a very smokey BMW last week and they are meant to be one of the cleanest.
Re: Peugeot306tld - Matt
Check the fuel consumption to see if there has been a drop. Mine smokes like hell during acceleration in every gear but still does 55 mpg and when I open the throttle to heat up and clear the exhaust still passes its MOT first time.

My previous Rover 2l diesel was just as bad, I had it for 80 000 miles and had new injectors at 50 000, that didn't stop it smoking. Everything was in order when it went to the garage for services etc and consumption was fantastic.
Black smoke. - David Woollard
Matt's post made me realise I was unsure of "pulling away". If you mean it dumps a load of black smoke, that then mostly clears, as you go on boost to pass another car...well this is quite common.

But if it lays a trail that obliterates the car behind as you "pull away" from a junction at normal speeds... that needs investigation.

Re: Black smoke. - Ian Cook
Just to follow David - if the smoke is really visible in daylight that's a possible problem. If you're worried because you see it at night in the rear view mirror with following headlights, then stop worrying - all indirect injection diesels do that.
Re: Black smoke. - Andrew Tarr
Whatever the identity of your 'black smoke', I'll bet a shot of Diesel conditioner in your next fill-up will reduce it.
LPG - Guy Lacey
If you want low emissions - go gas.

I would suspect any car trying to get up Bathwick Hill will smoke!

I would take the mota in for a decent tune up and focus on the cleanliness and state of the injectors and the settings on the fuel pump as this is the determinand for amount of fuel burnt and would contribute to schmoke.
Re: Diesel emissions - Stuart B
Alan said

?There is hardly a diesel that does not smoke (badly) when it pulls away accelerates or climbs a hill. That goes for brand new ones as well. Its time the manufacturers admitted the fact and stopped pretending that they are low on emmisions. I followed a very smokey BMW last week and they are meant to be one of the cleanest.?

I am surprised one of the real diesel heads has not picked up on this comment.

Diesel emissions.

CO2- diesel consistently better than petrol see Govt statistics

CO- diesel produces none due to running with XS air

NOx- diesel produces more when new compared to a petrol with 3 way cat, but over the life of the vehicle the petrol NOx emissions increase at a higher rate than the diesel NOx increases. At some point during the engine life, about 30k the curves cross and after that diesel produces lower NOx. When S levels in diesel fuel are reduced further it will be possible to sort this out also.

SOx- not seen comparative figures since ULSP became more widely available, prior to ULSD diesels generally gave off more SOx. The level will generally decrease with lower sulphur fuels, though red diesel has very high sulphur and yet almost no tax. Illogical Mr Spock. BTW Central heating oil also has high sulphur. Anybody got the up to date info?

HC- much lower HC given off by diesels.

VOC- negligible from diesel, petrol contains one of the highest known carcinogens benzene, and every time you fill up you breathe in a tankful.

So finally we get to the subject of the post, smoke or particulates.

Particulates are known to cause lung cancer in rats, but not hamsters or mice, therefore the mechanism is species specific. Other compounds also cause lung tumours in rats, eg chemically inert titanium oxide, which actually causes lung cancer in lower doses than diesel particulates. The particulates cause only lung tumours and nowhere else in the rats body. It is believed that the cause of the rats suffering from tumours is due to physiological differences between the species and the way they clear obstructions in their lungs. Basically hamsters can cough, rats cannot apparently.

So what does all this rat/hamster stuff mean for humans. Well you cannot do experiments on humans and personally I am not at all sure that such experiments ought to be done on animals but that is a debate for elsewhere than on this site however distasteful we might find such experiments. However humans have been exposed to diesel exhaust as a result of occupational exposure, eg working in enclosed spaces/mines/buildings where they use a lot of diesel engines. Results of such research show by long term exposure (like 30+ years) to diesel exhaust gives about a 1.33 times increased risk of getting lung cancer. Quite how they managed to calculate such an accurate figure is beyond me, it?s a bit like reporting miles per gallon to 15 dec places. Anyway the other thing that is important is that if we accept this 1.33x figure, the researchers themselves say that they cannot separate out accurately how much of this is due to active and passive smoking of tobacco.

Recent research suggests that a bigger problem might be small particulates, in that these are not filtered out by the bodies defence mechanisms, nose hair, and the various bits and bobs in the bronchial passages to the lungs, but that these small particles might get right down into the deep part of the lungs where they cannot be removed by coughing. Same problem as the rats, guess which internal combustion process produces these small particles, yes petrol engines, esp the direct injection sort. In order to give a balanced view actually we should not forget that the modern high pressure injection diesels also produce smaller particle sizes.

Time to take cover, head for the hay and let the debate commence methinks.

PS Guy Lacey FYI this is not pseudo academic piffle, it?s just the plain and simple facts!
Re: Black smoke. - Brian
I had a Ford Orion 1600 diesel that turned a yellow dinghy practically black between Essex and Bordeaux. I was recommended to change the injectors but that seemed to make practically no difference.
On the other hand my Pug 309 and 405 turbo have only smoked on hard acceleration. I towed the boat with the 309 and now tow the caravan with the 405 and neither have shown any obvious sign of smoke deposits.
It seems to be individual car characteristics rather than models. As other have said, injector condition, pump settings , quality of fuel, engine wear, etc. all seem to play a part.
Re: Black smoke. - Chris
Don't forget the air filter. When was it last changed? Is it fitted correctly? Could be as simple as a blocked or partially blocked air supply.


Value my car