Why Does My Exhaust Smell Like Gas?
If you’ve noticed a strong fuel odor coming from your vehicle’s exhaust, it’s more than just an unpleasant smell; but is an indication that there is something malfunctioning with your car.
Common Causes of Gasoline Exhaust Odors
Rich Fuel Mixture
When your engine burns more fuel than necessary, it creates a “rich” mixture. This excess fuel doesn’t completely combust and can result in a distinct gasoline smell. Potential culprits include:
- Faulty oxygen sensors – Oxygen sensors monitor the exhaust from your vehicle and tell your vehicle’s computer to adjust the amount of fuel that is being injected into the combustion chamber. If the sensor is faulty and it tells the computer to inject more fuel than is needed then the car won’t burn all of the fuel and the result is a gas smell out of your exhaust pipe.
- Malfunctioning mass airflow sensors – The mass air for sensor, or MAF, monitors the amount of air coming into the engine. It works in conjunction with the oxygen sensors to tell the vehicle’s computer how much fuel to inject. Much like a faulty oxygen sensor, if a MAF is giving an incorrect reading it can result in excess fuel being injected and cause a smelly exhaust.
- Faulty fuel injectors – Fuel injectors can fail in a couple of ways that cause excessive fuel to be sprayed into the engine. Injectors have very small holes to ensure the fuel is atomized and burned efficiently. If any of these get clogged then that can disrupt the spray pattern and cause incomplete combustion resulting in a poor running vehicle and a fuel smell out of the exhaust. Fuel injector seals can also fail. When this happens fuel is leaking into the combustion chamber when there shouldn’t be any fuel coming out of the injector. This can happen when the vehicle is running or any time that the fuel system is pressurized, like when you turn the key to the on position before you start your car.
Damaged Fuel Pressure Regulator
A failing fuel pressure regulator can cause excessive fuel to be released into the combustion chamber. This happens when the regulator is stuck open and it results in a rich fuel mixture. This leads to unburned gasoline entering the exhaust system creating that strong gas odor.
Worn Spark Plugs or Ignition System Problems
Worn spark plugs or ignition system components can prevent proper fuel combustion, resulting in unburned fuel exiting through the exhaust. You will typically have misfires and a poor running vehicle if your ignition system has failed to the point that you are smelling fuel out of the exhaust.
Leaking Fuel System Components
Damaged fuel lines, injectors, or fuel pressure regulators can cause fuel to leak, introducing raw gasoline into areas it shouldn’t be. While external leaks may not be causing a smell directly out of the exhaust it is good to be mindful of the possibility of leaks and the fire risk that they pose.
Why You Shouldn’t Ignore This Problem
A gas smell from your exhaust isn’t just unpleasant, but can cause other issues such as:
- Reduced fuel efficiency
- Potential engine damage from potential “fuel-washing” of the cylinder walls or in extreme cases hydrolocking resulting in damaged internal components
- Increased vehicle emissions and pollution
- Safety risks due to potential fuel system leaks
What Should You Do?
If you are experiencing a gasoline smell from your exhaust, don’t wait. Bring your vehicle to one of our Sun Automotive locations in Eugene, Springfield or Junction City Oregon. Our expert technicians will perform a detailed inspection of your fuel system and utilize our advanced diagnostic tools to pinpoint the exact issue.
Contact us or schedule an appointment online today at Sun Automotive and get “The Best Service Under the Sun” for your vehicle.