On my 2014 Corolla (40k miles), I am getting a very faint fuel odor around the fuel filler door. There is no check engine light on. I have already replaced the gas cap with a new OEM one from Toyota, but I'm still getting the faint fuel smell. I also notice that when tightening the cap, it clicks, but then bounces back a bit. Both the old and new caps do this. What is the likelihood of two defective fuel caps? Is this most likely a problem with the fuel filler neck or something else? The fuel odor is very faint, but I know it's supposed to be a sealed system.
Any thoughts you might have would be appreciated.
My car has 40000 miles.
My car has an automatic transmission.
This may be related to the fuel tank purging system. As you may know, all modern cars are equipped with an Evaporative Emission Control (EVAP) system. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the charcoal canister. The charcoal canister is filled with activated carbon pellets that can absorb the fuel vapors. When the engine is running, the fuel vapors are purged from the canister and burned in the engine. The vent control valve (solenoid) controls the flow of outside air in and out of the charcoal canister. When this solenoid is not working properly, this will cause excess pressure to back up into the tank resulting in the fuel cap being the path of least resistance. This may be what is causing it to back out on you. If you would like to have an expert check this out, a certified technician from YourMechanic can come to your car's location to inspect the fuel system for you and advising on a repair.
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