What are the causes of a car's rich air-fuel mixture?
2 Answers
The main causes of a car's rich air-fuel mixture include clogged air filters, faulty fuel pumps, and blockages in the carburetor. The specific causes and solutions are as follows: Clogged air filter: First, check the choke valve opening and adjust the fuel needle. Then remove the air filter screen to see if the engine performance improves. Inspect the pipeline from the fuel tank to the carburetor connector - fuel leakage or blockage can cause the mixture to become rich. The solution is to unclog or replace the components. Faulty fuel pump: Check the fuel pump as malfunctions can lead to a rich mixture. The solution is to replace the fuel pump. Carburetor blockage: Blockage in the carburetor's main jet or main fuel supply passage. The solution is to clean and unclog these components.
I was just tinkering with my old car in the garage. A rich fuel mixture is a pretty common issue—basically, there's too much gasoline and not enough air in the engine. The most common cause is a clogged air filter, where dust buildup blocks the air intake, restricting airflow and making the fuel seem excessive. Another issue could be faulty fuel injectors, like aging leaks or sticking, causing too much fuel to be sprayed without stopping. If the fuel pressure regulator is broken, the fuel pressure gets too high, and the fuel injection can't be controlled. Sometimes, the ECU receives wrong signals, like a temperature sensor falsely reporting the engine is very cold, prompting it to inject extra fuel to warm up. Don't underestimate this—if it gets severe, emissions can exceed limits, and you might even see thick black smoke. When parked, you might notice a strong gasoline smell from the exhaust. I often advise car owners to first replace the air filter, then check the fuel injectors. If that doesn’t work, it’s best to visit a repair shop.
