Mercedes GLC Diesel Engine Running Rich

My 2019 Mercedes GLC Diesel engine seems to be running excessively rich. At 10060 km, I've noticed reduced engine power, the check engine light is on, and the engine runs roughly. Also, fuel consumption has increased, and the vehicle jerks when accelerating. Could a defective injector be the cause?

4 comment(s)

A rich mixture can cause those symptoms. I had similar issues on my BMW. Check the air filter and whether the intake manifold is clean. A blocked air filter would reduce airflow, increasing the amount of fuel compared to air, resulting in a rich air-fuel ratio. Have you checked the spark plugs?

I appreciate the response. I haven't examined the spark plugs yet. If the rich mixture is caused by the air-fuel ratio, how would that relate to a defective injector?

The injector directly controls the amount of fuel injected. A faulty injector can deliver too much fuel, causing this rich running. Given the symptoms, it's plausible. However, start with cheaper fixes before replacing the injector. I would recommend visiting a workshop to get your diagnosis confirmed.

I appreciate the advice and have taken the vehicle to a workshop. The diagnosis confirmed a defective injector. The injector replacement cost 515€. Thank you again for your input.

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