BMW 335i XDrive Smells Like Gas

Common Causes of Fuel Odors in Your BMW 335i xDrive and Essential Safety Precautions

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Reviewed by
Bo Fader
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 335i xDrive 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 335i xDrive 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 Issues in a BMW 335i xDrive

When troubleshooting gas smell issues in your BMW 335i xDrive, it's essential to take a methodical approach to diagnose the problem effectively. Begin by checking the gas cap, as a loose or damaged cap is often the simplest issue to resolve and can lead to fuel vapors escaping. If the gas cap is secure, inspect the fuel system for any visible leaks, particularly around the fuel injectors and lines, as these areas can emit a gasoline odor or show signs of wetness. Next, assess the emissions control system, focusing on the catalytic converter, since malfunctions here can produce unusual smells and may trigger warning lights on your dashboard. If these checks do not uncover the source of the gas smell, evaluate the fuel tank, especially if you encounter difficulties while refueling or notice fuel leaking when the tank is filled to capacity. By systematically addressing these potential issues, you can pinpoint the cause of the gas smell and take the necessary steps to ensure your vehicle remains safe and performs optimally.

What Could Cause a Gas Smell in a BMW 335i xDrive?

When you notice a gas smell in your BMW 335i xDrive, it’s essential to investigate several common problems that could be at play. One of the first areas to check is the gas cap; if it’s loose or damaged, it can lead to fuel vapors escaping. Additionally, inspect the fuel system for leaks, particularly around the fuel pressure regulator and charcoal filter, as these components can deteriorate over time and cause odors inside the cabin. Another critical area to examine is the catalytic converter; a failing unit can not only trigger the check engine light but also produce unusual exhaust smells. If you’ve recently changed your spark plugs, ensure that the sealing washers are intact and that they are properly torqued, as improper installation can lead to fumes entering the fresh air intake. Lastly, consider the fuel pump connection, especially in older models, as a compromised connection can result in fuel leaks. By systematically checking these components, you can identify the source of the gas smell and take appropriate action to rectify the issue.

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

If you notice a gas smell in your BMW 335i xDrive, it’s essential to act quickly, as this could indicate a serious fuel leak that poses a fire risk. Start by thoroughly inspecting the engine bay and undercarriage for any signs of fuel leaks, as gasoline can evaporate rapidly, making leaks difficult to detect. Pay special attention to the fuel pressure regulator located under the driver side rear seat; it should be dry and functioning correctly. Additionally, check common leak areas, such as connections beneath the driver side floorboards and around the left rear wheel. Be vigilant for potential causes like a damaged fuel injector gasket or cap, which can also lead to fuel odors. If you’re unable to pinpoint the source of the smell or if the issue seems beyond your expertise, it’s crucial to seek assistance from a qualified mechanic or BMW service center. Ignoring these symptoms can lead to severe safety hazards and costly repairs, so addressing them promptly is vital for your safety and the integrity of your vehicle.

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