What causes the EA888 engine to report a rich mixture in cylinder 1 system?

[Kim]

The EA888 engine reporting a rich mixture in cylinder 1 system is due to increased carbon deposits in the combustion chamber, which reduce the combustion chamber volume, increase the compression ratio, resulting in higher cylinder pressure; an overly rich air-fuel mixture in the combustion chamber; or exhaust flow obstruction or a clogged catalytic converter can also lead to excessive cylinder pressure. Solutions to address the false impression of high cylinder pressure are as follows: 1. Use the natural cleaning method: You can drive at high speeds for a few trips to utilize the high-speed airflow to clean the combustion chamber. This method is suitable for vehicles with relatively short-term, minor, and soft carbon deposits. 2. Use a combustion chamber cleaner for non-disassembly cleaning: Excessive cylinder pressure in a car engine can cause engine knocking and difficulty starting. Uneven cylinder pressure across the engine can result in rough engine operation or misfiring. Insufficient cylinder pressure in the engine can lead to reduced engine power, increased fuel or oil consumption, excessive emissions, and difficulty starting.