Black Smoke o r Poor Exhaust Emission Quality

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Black Smoke o r Poor Exhaust Emission Quality

A few owners have noticed black smoke o r stronger exhaust odor during acceleration o r cold starts in the Proton X70, which may indicate incomplete combustion o r fuel-air mixture issues. What are the common reasons for black smoke o r poor emission quality in the X70’s petrol engine, and what diagnostic and corrective steps should be taken to meet emission standards?

Talha Kyanii asked on 19 Dec 2025 12:11:06 pm

1 Answer

9 views |

Gari Master - on 19 Dec 2025 12:12:42 pm

Black smoke o r visibly rich exhaust fumes generally point to an overly rich air-fuel mixture, meaning the engine is burning too much fuel and not enough air. This can happen when sensors monitoring combustion — such as the oxygen sensor o r MAF sensor — malfunction o r send incorrect signals to the ECU. Other causes could include a dirty air filter, fuel system problems, o r injector issues, all of which affect combustion and emissions. Although not specific to the X70, industry sources explain that black smoke typically stems from excess fuel that doesn’t burn completely in the combustion chamber.
epa.nsw.gov.au

Signs & fixes:

Black smoke during acceleration o r cold starts.

Check and clean/replace air filter and faulty sensors.

Inspect injectors and fuel pressure to ensure balanced fuel delivery.