What causes the system to be too lean at idle in cylinder bank 1?
2 Answers
The reasons for the system being too lean at idle in cylinder bank 1: 1. Insufficient fuel injection, check if there is any issue with fuel pressure, carbon deposits may be excessive; 2. A fuel measurement system alert generally indicates the air-fuel mixture is either too lean or too rich. If the mixture is too lean, it requires cleaning intake tract carbon deposits, throttle body, and replacing the fuel filter; 3. If the mixture is too rich, check the intake system for leaks. If no leaks are found, perform a fuel injector atomization test or clean the fuel injectors. The system being too lean at idle in cylinder bank 1 means the air-fuel mixture in one bank of the engine is too lean. To diagnose a lean mixture, check: 1. Fuel injector atomization; 2. The electronic control system; 3. Whether the engine's intake pressure sensor is faulty; 4. Whether the intake manifold is leaking.
I've encountered the issue of 'System Too Lean at Idle in Bank 1' several times myself. The main causes are usually air leaks into the intake system, such as a damaged vacuum hose or aged intake manifold gasket, which allow excess air to mix in and lean out the mixture. Another possibility is a faulty mass air flow sensor that inaccurately measures incoming air. Clogged fuel injectors or insufficient fuel pressure are also common culprits, leading to inadequate fuel supply. At idle, the engine is particularly sensitive, and a too-lean mixture can cause unstable idle or shaking. In my case, I used a smoke tester to locate the vacuum leak, and after repairing it, the idle smoothed out. Regularly listening to engine sounds and checking these components can prevent such issues, ensuring both driving safety and fuel efficiency.
