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post #1 of 5 (permalink) Old 1st May 2006 Thread Starter
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Smoking diesels?

My 1.9DCi smokes like mad when you give it a good bootfull! It is even worse now I've fitted a tuning box. I see a lot of diesels kick out smoke when they are thrashed, TDs particulary, but what actually causes this?
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post #2 of 5 (permalink) Old 1st May 2006
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Reckon it's got something to do with the extra fuel being pumped through.

My DCi has never really smoked badly either before or after fitting the tuning box, but if I floor it, I have noticed a slight smoke screen coming from the exhausts in the mirror

I'm sure someone will have a better idea than me!

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post #3 of 5 (permalink) Old 1st May 2006
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My old Lag1 in town traffic was very under utilised and belched out black smoke like hell, but if I took it on the M Ways and gave it a fair amount of wellie it cleared all the black rubbish out,,,,,,,,,,, but sooner or later when back in regular town traffic the same problem always returned.

S'funny you only occasionally see a similar problem with well maintained vans where the driver isn't the owner, in a case like this the driver is a lot more willing to take the rev's right up to the governor in any gear, and anywhere he / she can.
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post #4 of 5 (permalink) Old 2nd May 2006
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Isn't this something to do with common rail injection engines? My dad's brand new Merc used to do exactly the same when the engine was under load
post #5 of 5 (permalink) Old 2nd May 2006
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I think the smoke is just down to incomplete combustion when you're injecting large amounts of fuel.

The Euro IV emissions standard pretty much eliminates smoke production by diesel engines. From what I can see, manufacturers appear to be achieving this in one of two ways:
1) Restricting the engine to produce only about 80% of it's potential peak power.
2) Fitting a particle filter to trap the soot.

According to this Wiki article, particle filters are going to be mandatory on diesel engined vehicles in the EU from 2007. Whether or not this will be the case for cars that can meet Euro IV without a filter remains to be seen. Common sense says it shouldn't be, but then they insisted on making catalytic converters mandatory on petrol engined cars, even though lean burn technology (which isn't compatible with the cat) might have proved to be more effective in reducing overall polution.
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