The Answer is in the Smoke

We can generally understand what is wrong with a diesel engine by the colours of smoke emitted from the exhaust. There are three basic colours - black, white and blue.

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, defective or incorrect atomisers. (injectors need attention at about 100.000 to 120 000 Kms)
  

• Faulty injector pump     
  

• Incorrect fuel injection pump timing or incorrect valve timing.
  

• Poor engine compression
  

• Dirty air cleaner
  

• Turbocharger or intercooler faulty, poor boost pressure
  

• Problems within cylinder head, valves clogged up due to faulty EGR (exhaust gas recycling unit)
  

• Exhaust system restriction
  

• Defective "Thermostart" (Cold starting aid)
  

• Incorrect valve clearances.
  

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
  

• Incorrect grade of oil used.
  

• Poor compression