Choosing the right fuel may seem simple, but it directly affects the engine’s performance, durability, and lifespan.
Using low-quality gasoline - of unknown origin, containing impurities, or with a low Octane number - can cause severe damage to the fuel system, combustion chamber, and exhaust after-treatment system.

Below are four major technical consequences that vehicle owners should be aware of:

1. Damage to the Fuel Injection System and Combustion Chamber

Symptoms:

• The vehicle is hard to start, idles roughly, and accelerates poorly.
• The engine vibrates, emits black smoke, and consumes more fuel than normal.

Technical Cause:

Low-quality gasoline often contains impurities, water, paraffin, sulfur, and organic contaminants.
These deposits adhere to and clog electronic fuel injectors, causing uneven or improper fuel atomization.
As a result, carbon deposits build up inside the combustion chamber, leading to incomplete combustion.

Consequences:

• Loss of engine power and increased fuel consumption.
• Excessive combustion temperature, which can cause piston damage, valve cracking, or spark plug failure.

2. Engine Knocking and Power Loss (Pre-ignition / Detonation)

Technical Cause:

Gasoline with an Octane Number (RON) lower than the manufacturer’s specification leads to premature ignition (pre-ignition or knocking) - when the air-fuel mixture ignites before the spark plug fires.

Consequences:

• Noticeable metallic knocking or pinging sounds from the engine.
• Sudden spikes in combustion pressure cause strong impacts on pistons, connecting rods, and bearings.
• Reduced engine power, localized overheating, and a significant decrease in engine lifespan.

3. Damage to the Exhaust After-treatment System (Catalytic Converter)

Technical Cause:

Contaminated gasoline may contain sulfur compounds, heavy metals, or non-standard additives, leading to incomplete combustion.
The by-products - such as SOx, carbon soot, and lead residues - accumulate inside the catalytic converter.

Consequences:

• Blockage of the catalyst surface, increasing exhaust back pressure.
• Reduced conversion efficiency, causing the vehicle to fail Euro 4-5 emission standards.
• Excessive heat buildup in the converter can melt or fracture the ceramic substrate inside.

4. Corrosion of the Fuel Tank and Fuel Lines

Technical Cause:

Low-quality gasoline may contain water, impure ethanol, or acidic contaminants.
These substances cause metal oxidation, leading to rust inside the fuel tank and lines.

Consequences:

• Rust flakes and sludge contaminate the fuel pump, filter, and injectors.
• Resulting in fuel pump seizure, reduced power output, and shortened fuel system lifespan.

Technical Recommendations and Safe Usage

Conclusion

Cheap, poor-quality gasoline doesn’t just reduce performance - it destroys the engine from within.
A small saving at the pump can lead to repair costs many times higher than the initial amount saved.

Always choose certified, high-quality fuel, perform regular maintenance, and follow the manufacturer’s recommendations to ensure long-term engine reliability and safety.