Car won't start after filling up

Quick question for anybody out there. I took a cross-country trip last month in my 2000 Hyundai Sonata. About 4,000 miles into the trip, after numerous fill ups with no problems, I filled the car up and when I went to start it, it turned on, got to about 1,000 rpms and sputtered out almost immediately. I did the same a few more times with the same result. I ended up having to rev the engine a few times and then kicking it into gear immediately to keep it from shutting off on me. For the rest of the road trip thereafter, and up until now, the same problem occurs when I get gas. But ONLY when I get gas. Any other time the car starts fine.

I’ve tried taking the gas cap off and putting it back on without filling up and the car starts fine. I just had it in the shop and they said they couldn’t find any codes in the car indicating there was a problem at all with the engine in the recent past so no luck there.

Any thoughts on what this might be? I can live with it because I’m eventually able to get the car started, but it is annoying.

Thanks for any help!

It sounds like your car is starved for fuel. Why is the mystery.

Stopping the car for gas is the only time you turn the engine off for 2 minutes. Other stops are probably longer (restroom, food, etc). You said you tried just taking off and replacing the gas cap. Did you do this test under the same conditions as when you experienced the problem (long hot drive)? What happens if you only fill up the tank half way? What happens if you leave the gas cap off after the fill up?

When you suck gas out of the tank for the engine, something has to replace it, and that something used to be air, leaking in through vent holes. But now, gas tanks are sealed systems to reduce pollution and the air comes from the engine by via of vacuum lines and canisters that trap vapors to be burned in the engine rather than released into the atmosphere.

I would guess that you either have a weak fuel pump, or a problem in the gas tank ventilation system. But a ventilation problem would probably set the check engine light, so I’m puzzled.

You could also have vapor lock (gas in the fuel system gets hot and goes to vapor, which prevents liquid gas from getting from the tank to the injectors). This could also be related to low fuel pressure, or a bad check valve, or to worn out rubber in the fuel lines under the hood.

Next time you fill up, try driving off without the gas cap. That will set the check engine light, but it would allow you to determine whether your car is starved for gas due to a gas tank ventilation problem. (After you replace the gas cap and run the car through a few start/stop cycles, the check engine light will go off when the computer no longer detects the problem.)

Hey thanks so much for the suggestions. After initially telling me they didn’t know what the problem was, the folks at the repair shop said I have a bad canister purge valve. Does that sound about right? I checked prices for this part and they were only $25 or so, but they estimated $130 for the repair. Is this a difficult fix?

Thanks again for taking the time to respond. I really appreciate the help!

Well, the canister purge valve is part of the system I described so it is definitely plausible. The repair cost includes labor, you can ask them how they calculated it.

Most shops use a manual that says how many hours each job should take and they bill by the manual instead of by actual time. That way, you don’t get overbilled if an underskilled mechanic takes forever, but you also don’t get the benefit of a really good mechanic who is faster than average. But at least it is a pretty standard method that everyone seems to use so you can compare from shop to shop.

Are you adding more gas after the pump handle clicks off the first time. If so, next time the gas pump handle clicks off, so right there, do not even round off to the next nickel or dime. Just stop and put the handle up.