Encontrei esta informação em um site inglês, espero que nunca seja necessário, mas se for espero que ajude!
"Black Smoke
This is due to a air to fuel ratio imbalance, either the fuel system is delivering too much fuel into the engine or there is not enough clean air (oxygen ) a few things to look for :
Faulty injectors (injectors need attention at about 100.000 to 120 000 miles)
Faulty injector pump
Dirty air cleaner
Turbocharger or intercooler faulty
Problems within cylinder head, valves clogged up due to faulty EGR (exhaust gas recycling unit)
White Smoke
Normally means that the fuel injected into the cylinder is not burning correctly. The smoke will burn your eyes.
Engine/pump timing out
Fuel starvation to the pump causing the pumps timing not to operate correctly
Low engine compression
Water/petrol in the fuel
Blue Smoke
The engine is burning engine oil
Worn cylinders or piston rings
Faulty valves or valve stem seals
Engine over full with engine oil
Faulty injector pump/lift pump allowing engine oil to be mixed with the diesel
"
Carripana on the way ...
"Black Smoke
This is due to a air to fuel ratio imbalance, either the fuel system is delivering too much fuel into the engine or there is not enough clean air (oxygen ) a few things to look for :
Faulty injectors (injectors need attention at about 100.000 to 120 000 miles)
Faulty injector pump
Dirty air cleaner
Turbocharger or intercooler faulty
Problems within cylinder head, valves clogged up due to faulty EGR (exhaust gas recycling unit)
White Smoke
Normally means that the fuel injected into the cylinder is not burning correctly. The smoke will burn your eyes.
Engine/pump timing out
Fuel starvation to the pump causing the pumps timing not to operate correctly
Low engine compression
Water/petrol in the fuel
Blue Smoke
The engine is burning engine oil
Worn cylinders or piston rings
Faulty valves or valve stem seals
Engine over full with engine oil
Faulty injector pump/lift pump allowing engine oil to be mixed with the diesel
"
