The year, make, model and engine size would help us answer that one for you.
van gogh was poor.
On the contrary - he was poor and unknown.
Contact any auction company, e.g. Sotheby's or Christies. If you have a genuine van Gogh you are going to be rich.
A leaking fuel injector can cause a rich condition on one bank of the engine.
The best way to fix an alternator is to replace it with a rebuilt one from the auto parts store.
We need to know the year, make and engine to help you.
Defective oxygen sensor, the check engine light should be in your face if it is running rich (black smoke).
Adjust the fuel/air mixture, ensure you have an unclogged air filter/air cleaner.
It will be smoking black out of the exhaust / Running RICH. Spark plugs will be fouled out/ Black. Replace them if it is running rich. Plugs will not fix your problem. Replace map sensor.
I will fix it
You may have a bad catalytic converter. This may also be caused by an engine running rich which is a number of possibilities.
To fix a 1988 Nissan Pulsar running rich, start by checking and replacing the air filter if it's clogged, as this can restrict airflow and lead to a rich condition. Next, inspect the fuel injectors for leaks and clean or replace them if necessary. Additionally, test the coolant temperature sensor and oxygen sensor, as faulty readings can disrupt the fuel-to-air ratio. Finally, ensure that the engine's vacuum lines are intact, as any leaks can also contribute to a rich mixture.
Your civic could be running too rich because you used bad gasoline. It could also be running rich if a spark plug needs replaced.
If the fuel is running too rich in a car, it would be a good idea to adjust the EFI or Electronic Fuel Injector (carburetor). It would also be a good idea to make sure that all of the air cleaners and oxygen sensors are clean and functioning properly.
van gogh was poor.
You need to make sure that the pulleys are all running in a straight line.
You can't fix it till you know what's wrong with it.