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Is it possible to put too much gas in the tank?

My problem started about 6 months ago. Every morning, on the first start of the day, I can smell gas. Inside & outside the car. Pretty strong. After about 5 minutes, it goes away. Does not happen again until next morning. Even if it sets for 10 hours and started up in the afternoon, no smell. Only in the morning on the first start up. Car starts fine hot or cold any time of day no matter what the outside temperature is. Doesn’t matter how much gas is in the tank. 3.1V6, Chevy Malibu,114,000 miles. Gets about 32 to 34mpg. The only thing I have done is replace gas cap. No go. I cannot find a leak and fuel pressure is within specs. No fault lights either. When I fill up I have a habit of getting as much gas in as possible. Prices going up almost daily if not weekly. Bad reason for doing this I know. I have been told it can cause the fuel vapor canister to become saturated. I haven’t checked it yet. I’ve been to several major parts stores and they ALL tell me I have to go to a dealership to get that filter. Coo Coo Ka Choo.

If you top off the gas to the very top when you fill up you might have a bad canister. If you stop filling as soon as the pump valve clicks off and don’t add more gas after that, then the canister is OK. Usually a CEL will go on if the canister is bad as part of the car’s emission control system.

If there is no check engine light you might have a slight fuel leak somewhere in the motor compartment. When you stop the car the vaporized fuel might enter into the cabin via the fresh air vent in front of the windshield. Fuel vapors are dangerous, so you really need to find the source of this problem and get it corrected.

Please, in addition to the replacement parts for which you may have to pay for, consider the the environment. Yes, yours may not in and of itself be a big deal, but consider everyone else who does this and together it does make a significant impact. Instead of trying to overfill your tank if you’re worried about price increases, just buy a gas can and fill if with your car, leave it at home and dump it in as you need it.

Overfilling leaves you more inclined to have “smell” problems related to expansion and contraction as the temperature changes.

You do not need to buy a new canister just yet, just stop overfilling and it will take care of itself. But I think Uncle Turbo is right, you have a leak somewhere.

I can’t tell you when the purge valve purges the canister (which it does) - I think its different on different systems.

But if yours purges on a cold start - and if you had a contaminated canister - and a broken evap line after the purge valve - that could explain it all. Many will want to say - oh but the check engine light would be one. Maybe, maybe not. Those things aren’t as “smart” as they are often given credit for. I once drove around for a good month smelling fumes at idle. I finally found my main evap feed from the tank had worked itself free of its clip, fallen on the EGR tube and melted in two. If the computer “knew” anything about this, it didn’t decide to “tell” me about it.