Black Exhaust Smoke: Identify the Causes and How to Overcome It
The emergence of black exhaust smoke from cars often makes drivers worried. In addition to disturbing other drivers and causing air pollution, this black exhaust smoke can be a sign that something is wrong with the car's engine.
This condition usually occurs due to incomplete combustion inside the engine, resulting in abnormal exhaust smoke. The characteristics are that the exhaust smoke is too thick and black, accompanied by a burnt smell.
There are several factors that cause black exhaust smoke in cars.
1. Too much fuel mixture
The first factor that triggers black exhaust smoke in cars is too much fuel mixture, causing gasoline not to mix with air molecules in the correct ratio. Thus, when the engine starts, the spark plugs do not burn perfectly.
If there is too much fuel mixture, the emissions of waste gases from the exhaust will be thicker and irritating to the eyes.
2. Damage to the injection system
The injection engine uses a sensor to release a certain amount of gasoline into the engine. When the injection system has problems, the mixing ratio of gasoline and air becomes imperfect in the combustion chamber.
3. Dirty air filter
The main function of the air filter is to filter and clean the air from dirt through a filter made of dry paper. If the surface of this filter is filled with sand, dust, and dirt, it is likely that this dirt is blocking some important channels.
Indirectly, this condition can cause the exhaust smoke to turn black. In some cases, that dirty air contaminates the MAF, IAT, and MAP sensors located along the air induction hose. Thus, its function for sensor reading becomes inaccurate.
4. Idle Air Control (IAC) stuck or problematic
The IAC valve functions as a regulator of air passing through the idle channel in the throttle body. Its operation is that if the valve opens fully, the channel will open wide, resulting in a lot of air entering the intake manifold (a component that functions to channel the fuel and air mixture from the mixer to the combustion chamber or piston).
But if this valve opens only slightly, the result will be a narrower idle, causing the air supply to be restricted. Meanwhile, gasoline that continues to be supplied in the same volume can cause the air and gasoline mixture ratio to be incorrect. This is what has the potential to produce thick exhaust gas emissions.
How to overcome it
Fixing a car exhaust that emits black smoke can be done in various ways.
1. Re-tune the carburetor
The carburetor setting should be the first suspicion if black smoke comes out of the car's exhaust. This is because the carburetor determines the ratio of air to gasoline. The method is also quite easy; you need to re-adjust the fuel mixture from the adjustment screw on the carburetor.
If the black smoke issue occurs at idle RPM, it is caused by an incorrect idle air mixture. The solution is simply to turn the screw left or right until you find the ideal result. However, if the smoke issue occurs at high or medium RPM, there may be damage to the main jet inside the carburetor. You will need to replace the entire carburetor unit to resolve this issue.
It's a different story if black smoke only appears when the car is going uphill or under heavy load. This condition could result from the power system in the carburetor supplying more gasoline. This issue tends to be normal and does not indicate damage.
2. Clean the cylinder chamber
Excess leftover fuel is one of the causes of thick black exhaust smoke. You need to take the car to a workshop to clean the cylinder chamber from the leftover fuel that has settled.
3. Repair the injection system
The check engine light will turn on if a fault is detected in the sensor or injector. It is better to take the car to a trusted workshop or authorized service center for a machine checkup. With special scanning tools, issues occurring in the sensor or the accuracy of the injection system can usually be easily detected.
4. Regular car service
A surefire step to prevent and address black smoke coming from the car's exhaust is to perform regular servicing. Whether it's changing oil, cleaning filters, or if something needs to be replaced, the workshop will inform you immediately.
Easy ways to detect early problems in cars
Besides looking at the black smoke billowing from the exhaust, there is actually an easier way to detect if the car is having problems with the combustion system, which is to look at and touch the end of the car's exhaust with your finger.
Of course, this method should be done when the car's engine is off and has been parked for a while! The ideal time is in the morning before the car is warmed up. If you see black dust, you can be sure the problem lies in the combustion system.
Incomplete combustion is caused by dirt in the air entering from a dirty filter. Then, if you feel an oil leak at the end of the car's exhaust, it can be predicted that there is a problem with the valve seal, piston ring, or cylinder wall.
The logic is similar to the combustion system in a motorcycle. If the piston is worn out, oil can seep into the combustion chamber and will exit through the exhaust. If this condition is left unchecked, it can reduce the car's performance.
It's a different story if the dust that sticks to your fingertip is gray. This indicates that the car's engine is in good condition.
Observing the car's condition through the color of smoke coming from the exhaust
The smoke coming from the car's exhaust can identify problems occurring in the internal engine. Besides black smoke, there are at least three other colors of exhaust smoke that also indicate that the car needs to be checked immediately.
1. Gray smoke
In manual cars, gray exhaust smoke indicates damage to the PCV valve. This valve may be stuck, causing the usp and gas entering the engine compartment to be uncontrolled.
If in automatic cars, a leak in the transmission oil must be checked immediately. It could be that the oil is leaking or too much in the tank.
2. White exhaust smoke
If the white smoke that comes out is thin and only appears in the morning when the car is warmed up, you don't need to worry. This is a process of condensation or natural dew caused by environmental weather. When the car has been parked for a long time and is just warmed up, thin smoke along with water droplets will come out.
It’s different if the white smoke that comes out is thick and dense. It could be that oil is also being carried into the combustion chamber, where only fuel should be processed.
3. Blue smoke
For cars using turbo, blue smoke often appears. This could be a sign that there is damage to the turbo blower that is rarely serviced, a gasket, or even a worn piston ring. This condition causes oil to also burn.
Author: Dinno Baskoro
