BMW 335is Smells Like Gas

Common Causes of Fuel Odors in Your BMW 335is and Essential Steps to Address the Issue

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Reviewed by
Aisha
Written by RepairPal Car Genius
Updated January 14, 2025
0%
15% chance it's the
Gas Cap
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40% chance it's the
Emissions Control System
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45% chance it's
Something else
The most common reasons a BMW 335is smells like gas are the gas cap, the fuel system, or the emissions control system.
  • Gas Cap: A loose or damaged gas cap can cause fuel vapors to escape, triggering the check engine light and potentially affecting fuel system pressure.
  • Emissions Control System: A faulty emissions control system can lead to increased hydrocarbon emissions and trigger the check engine light due to malfunctioning components like the EGR valve or O2 sensors.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a BMW 335is smells like gas?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

A failing catalytic converter can cause a vehicle to fail emissions tests and turn on the check engine light. The exhaust might have an unusual smell. A restricted catalytic converter can result in a loss of engine power.

» LEARN MORE: How to tell if your catalytic converter is failing

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. The canister may also cause difficulty starting the engine, a rough idle, and poor fuel mileage.

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. A fuel tank leak may also cause difficulty starting the engine, a rough idle, and poor fuel mileage. When a fuel tank is simply corroded to the point of failure, the exterior tank condition rarely shows damage. The inside of the fuel tank will be rusted or corroded, and rust flakes or other debris may be floating in the fuel.

For most vehicles, the only symptom will be a check engine light or fuel tank filler cap light illuminating on the driver instrument cluster. This is to signal that there is an evaporative emissions (EVAP) leak. In some situations, the vehicle may take longer than normal to start, or, more rarely, the engine may not start at all. on-board diagnostic (OBD) trouble codes will refer to EVAP system failures such as a small or massive EVAP system leak. Lastly, the powertrain control module may notice a lean running condition, which could even lead to random and infrequent misfires.

Troubleshooting Gas Smell in a BMW 335is

When troubleshooting a gas smell in your BMW 335is, it's essential to adopt a systematic diagnostic approach that prioritizes simpler fixes before delving into more complex issues. Start by checking the gas cap; ensure it is securely tightened and inspect it for any signs of damage, as a loose or faulty cap is a common culprit for fuel odors. Next, examine the fuel system for leaks, particularly around the fuel injectors and hoses, as these components can develop cracks or malfunctions over time. If you notice any fuel residue or a strong odor near the engine bay, it may indicate a gasoline leak that requires immediate attention. Additionally, inspect the emissions control system and the charcoal fuel filter, especially in hot weather, as these can also contribute to gas smells. Pay close attention to rubber O-rings and seals, as they can dry out and crack, leading to fuel leakage. Lastly, check the valve cover gasket for any oil leaks that might be dripping onto the exhaust manifold, which can create a gas-like smell in the cabin. By methodically addressing these areas, you can effectively diagnose and resolve the gas smell issue, ensuring a safer and more comfortable driving experience.

What Could Cause a Gas Smell in a BMW 335is?

When you notice a gas smell in your BMW 335is, it’s important to act quickly to identify and resolve the issue for both safety and performance reasons. A fuel leak is often the primary suspect, which can arise from damaged fuel lines, faulty fuel injectors, or a leaking fuel tank. Additionally, a loose or damaged fuel cap can permit fuel vapors to escape, leading to an unpleasant odor inside the vehicle. Another potential source of the smell could be a clogged or malfunctioning fuel filter, which may cause fuel to leak or evaporate. Problems with the evaporative emissions system, designed to capture and recirculate fuel vapors, can also contribute to the gas smell. Lastly, consider the possibility of exhaust system leaks, such as cracks in the manifold or damaged gaskets, which can allow gas odors to enter the cabin. While some of these issues may be addressed through DIY methods, it’s advisable to consult a qualified mechanic for a comprehensive inspection to ensure your BMW remains safe and reliable.

What Should You Do If Your BMW 335is Smells Like Gas?

If you notice a gas smell in your BMW 335is, it’s crucial to act quickly, as this could indicate a serious issue that poses safety risks. Start by checking the gas cap; a loose or damaged cap is a common culprit and can easily be fixed. Next, inspect the fuel system for any signs of leaks, as even a small fuel leak can lead to dangerous situations. Additionally, consider the emissions control system, as malfunctions here can also contribute to gas odors. Ignoring these symptoms can lead to more significant problems, including fire hazards or costly repairs down the line. If you’re unable to pinpoint the source of the smell or if the issue persists, it’s wise to consult a professional mechanic. Prioritizing safety and addressing these concerns promptly will help ensure your vehicle remains in good working condition.

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