A bit of smoke from the exhaust is normal. But what if suddenly all you can see in the rear-view mirror is a black bank of fog? Unusual exhaust gas colors can have several causes, some of which can be rectified quickly and easily.
Others come close to completely rebuilding the engine. Let me take a deep breath and tell you what the colour of the exhaust gases reveals about the engine’s condition.
In a well-functioning engine, only petrol or diesel is burned. It creates various combustion products that get into the environment through the exhaust.
CO2 makes up most of this mixture of substances, but it also contains hydrocarbons, nitrogen oxides, and carbon monoxide. None of these substances are really visible.
So what you see coming out of the exhaust is a mixture of the finest soot particles and condensation.
The latter occurs when hot gases meet colder ones. The contrails in the sky are also formed in this way.
However, if the engine no longer runs smoothly, the composition of the emitted mixture often changes, with it the exhaust gas’s color.
If your car emits thick black smoke while driving, you either have a problem with the lambda sensor, the spark plugs, or the car’s engine management system.
Black smoke is caused by incomplete combustion. Fuel residues become sooty and escape from the exhaust. The black smoke is the result.
Fortunately, such errors are mostly routine problems and easily fixed. However, a visit to the workshop will still be necessary because the complex electronic systems that are in a modern car cannot be serviced in the driveway at home.
There are several reasons for black smoke coming out of a car. Contrary to popular belief, burned engine oil is not an option because it causes blue smoke. Possible causes of black smoke include:
- deposits in the exhaust
- a too rich fuel-air mixture
- contaminated fuel
- an improperly functioning exhaust gas cleaning system
- admixtures to the fuel
- a clogged air filter
- a defective turbocharger
- low temperatures
- an incorrectly adjusted ignition or control
Some causes of black smoke are specific to petrol engines, some are specific to diesel engines, and some are independent of the engine type.
If dark or black smoke comes out of the exhaust, you can assume that too much fuel has been injected (“mixture too rich”) or that combustion is not taking place correctly.
Another thing you must observe is exactly when the car emits dark smoke. For example, this can occur mainly after starting or when accelerating.
You can learn more about typical causes, necessary repairs, and all the costs involved in the following guide!
The diesel scandal affects vehicles from VW, Mercedes-Benz, BMW, Audi, Skoda, Seat, Porsche, Volvo, Opel, and other manufacturers.
Due to current court judgments (e.g., BGH judgment of 21.2.22), there are always new decisions in favor of consumers.
Let me assist you in writing details of the causes of black smoke
Air mass meter defective
The air mass meter (LMM for short) is a sensor that records the exact air mass of the air sucked in by the engine. In this way, the engine control can calculate the fuel required in each case.
If the defective sensor, the engine control unit may inject too much fuel (mixture too rich) incorrectly. The injected fuel is not completely burned and can cause dark smoke from the exhaust.
The air mass meter must be replaced with a new part if it is defective. You can find more information about the repair in this separate guide.
The coolant temperature sensor
(also called coolant sensor, coolant temperature sensor, or engine temperature sensor) constantly records the temperature of the cooling water.
A defect can cause the engine control unit to incorrectly inject too much fuel, for example, because it constantly assumes that the engine is still cold.
As a result, it may also be possible that the additionally injected fuel is not burned correctly and causes dark smoke.
Lambda sensor defective
Lambda sensors determine the oxygen content in the exhaust gas and pass the values on to the engine control unit. They are, therefore, largely responsible for an optimal fuel-air mixture.
A defective probe can result in incorrect values being passed on to the engine control unit, which may incorrectly inject too much fuel (mixture too rich).
Here, too, it is possible that the additionally injected fuel is not burned correctly and causes dark smoke. The check engine light typically lights up if the lambda probe is defective.
Fuel injection problem
Defects in components around the fuel injection system can ensure too much fuel is injected.
Depending on the design of the engine, dripping injectors, a defective injection valve, or defective pump-nozzle elements can all be considered.
As a result, in addition to increased fuel consumption, this can also result in dark smoke from the exhaust.
Diesel particulate filter full/clogged
A full or clogged diesel particle filter can ensure that fuel combustion no longer takes place correctly and the engine runs too rich.
It is when the cylinder can no longer be completely emptied during gas exchange due to excessive exhaust back pressure.
As a result, this can lead to dark colour smoke from the exhaust. If the diesel particulate filter can no longer be regenerated, it must be removed, burned free, or replaced.
While regenerating the diesel particulate filter, a strong cloud of black soot escapes from the exhaust for a short time.
This can sometimes be observed with cars driving ahead on the freeway.
HOW DO YOU FIX BLACK SMOKE FROM YOUR EXHAUST
What should I do if black smoke comes from the car’s exhaust pipe? The exhaust trachea is like our human nose, removing waste from the body and breathing fresh air.
When driving, there are times when the exhaust pipe is damaged or black smoke is emitted. Now there are very few on the street. There used to be many such cars.
What is the reason? Today, let me tell you the solutions to the black smoke from the exhaust.
In the usual maintenance, you should also check the ageing degree of the carburettor and other parts; you should carry out regular maintenance and recovery. You must take note of how you drive.
For EFI vehicles, check the cylinder line every 30,000 kilometres, check the spark plug every 10,000 kilometres, and replace the new parts when they need to be replaced.
Therefore, those faults of the car it is not unavoidable.
As long as the car owner pays more attention to inspection and detailed maintenance, many car faults will not impact their driving.
IS IT BAD IF MY CAR BLOWS BLACK SMOKE
You are reading these articles because your car is smoking black smoke. And you want to know if it is normal or you should attend it.
If the ambient temperature is low and the black smoke only appears within a few seconds of starting, it is a normal phenomenon.
It is because the temperature of various parts of the engine is too low when starting, and the fuel combustion is not fully formed.
It is definitely not normal if it takes a long time or black smoke has been emitted.
It means that the engine mixture is too rich and the combustion is insufficient, which manifests in engine failure.
Black smoke from the engine exhaust pipe indicates that the engine is not working well and that the mixture of the fuel supply system is too rich, indicating that the vehicle load condition does not match the actual fuel injection amount.
So if you are experiencing such a thing, it is a signal that urgent attention is required of y look for a solution to stop the black smoke before it leads to a bigger problem.