Diagnosing your Diesel Engine using the Exhaust Fumes
More recent makes of diesel engines – those manufactured in 2008 and newer models – are equipped with special DPF, DOC, SCR exhaust treatment systems. These exhaust-after treatment systems ensure your vehicle doesn’t give off smoke. Old diesel engines, however, give off some smoke, this is partly due to the fact that they are not equipped with these exhaust-after treatment systems.
Whether your diesel engine driven vehicle is old or not, there are times you will see smoke in the exhaust fumes. The smoke as you may have noticed is usually white and appears early in the morning. But as the temperature of your vehicle steadily rises, it should clear out. If your diesel engine is the emitting smoke of a different color at other times of the day, is a strong indication that something is wrong. Read on to find out what it means.
Sometimes it may appear to be a deep shade of gray. This color of smoke is emitted due to the incomplete combustion of fuel in the engine . The reasons fuel is burned incompletely could one or all of the following reasons:
- Imbalance of air-fuel proportion in the combustion chamber
- Inadequate air to aid in combustion of fuel
- Excess fuel in the combustion chamber
- Faulty injector causing fuel to flow a little too soon.
It’s not uncommon for drivers to complain of unusual oil consumption when their vehicles start emitting this color smoke. Blue smoke indicates the presence and combustion of engine oil in the combustion chamber. This is not healthy as oil has no business being in this chamber – the combustion chamber is for air and fuel. Oil in the chamber is as a result of the following
- A loss in the integrity of Turbo Charger seals
- Failed valve seals
- Worn out piston rings
As earlier mentioned, white smoke is usual if your engine is cold and just running for the first time on a colds morning. Once it gets warmer, the smoke clears out. However, if white smoke is still a constant occurrence, it’s an indication that particles of fuel are leaking the combustion chamber without burning. This is usually associated with low temperatures in the engine.
Sometimes just changing the fuel injector, piston rings, valve and turbocharger seals will clear out the fumes. Other times the state of your engine is to blame. If that is the case, run a compression test on all the cylinders to confirm if the engine builds at least 350 psi. If it’s a straight pass on all the cylinders, examine the turbo intake pipe for the presence of engine oil.
Knowing what the color in your exhaust fume is saying about your diesel engine health will help you quickly diagnose and solve the problem.