Gas Fill-up Causes Car to Flood?

Hi, I have a 2000 Hyundai Sonata, bought used (single-owner) at 147,000 miles. Currently has 150,000 miles on it. Has been running great.

Here's my problem. The last two times I have filled up my car, it has flooded the engine. Or at least it seems to have flooded the engine, I don't know much about cars so it could be something similar. The engine turns over, idles at a low RPM (the needle stays at a low RPM and goes up and down) and then dies. Engine light on.

The first time the problem was solved by waiting for maybe 5 minutes, continuing to try to start it. I think I caught it once when it was idling and gave it some gas and it stayed going.

The second time it happened it was worse, I had to wait maybe 10-15 minutes and then I finally got it going by pressing the accelerator to the floor when I started it. That worked like a charm on the first try.

Other than that it seems sometimes as though it is wanting to die a little bit when it is idling, but it may just be me overreacting. I guess I didn't pay enough attention to the idling when I first got it.

Anyway, the problem seems to be very linked to me filling up my gas tank. Anyone have any ideas as to what the problem could be? And maybe a potential solution? I'm gonna fill up again tonight, but keep my car running while I do it (I just recently left my lights on and drained the battery so I don't want to risk needing to start it multiple times). If something happens of note I'll let you all know.

Thanks in advance!!

Have you checked the diagnostic codes to see what they indicate? That would be step number one. Of course by filling it while the engine is running will certainly cause a code or two (not to mention the potential safety risks to you and others).

If the car is flooded (which I doubt) you could try holding the throttle all the way to the floor while cranking. This Wide Open Throttle (WOT) condition causes the engine to go into "clear flood" mode, shutting off the fuel injectors to clear a flooded condition.

It sounds like you might have either an issue with the fuel cap not properly pressurizing the system or possibly a evaporative emissions purge solenoid system issue.

-Rod

If the car is flooded (which I doubt) you could try holding the throttle all the way to the floor while cranking. This Wide Open Throttle (WOT) condition causes the engine to go into "clear flood" mode, shutting off the fuel injectors to clear a flooded condition.

This is what I did the 2nd time the car "flooded" and it worked. Does that mean that my car was indeed flooded? Or do you think it was just a coincidence?

filling up the tank shouldn't have any connection to how it runs. The only thing I can imagine happening is the EVAP cannister is getting raw gas in it, but the purge valve should be closed at start up/idle

Whether it is full of gas or whether the purge valve is leaking, you would get a code most likely

Does the check engine light stay on all the time? Either way, you should check the codes that are stored on the computer


One thing though, if there is gas in the cannister, that happens from overfilling the tank. You never "top it off", when the station hose shuts off, don't try to put any more gas in it. It will overflow the tank vent and fill the cannister and that is bad

How do I check the codes stored on the computer? Will I be able to see the codes that came up when I last filled up last Friday?

No, the check engine light does not stay on all the time.

And I do not ever "top off" the gas tank when I fill it.

Thanks for the suggestions, keep 'em coming if you have more to add! :)

i just worked on a ford ranger and it sounds like same problem. it was the maf and 0'2 sensor..some mfs you can take apart and clean the screen..

An Update:

On the way home from work today I filled up my gas tank. Same problem as before. I did the "WOT" method mentioned above and that got the car to start. The car died at the stoplight at the corner and I had to do it again, which worked, and then I rolled stop signs all the way home to make sure it didn't happen again.

I did notice the lights that were on when this happened, so I think I'm gonna go take a look at the owner's manual and see what it says about that.

If anyone knows anything about Hyundai Sonatas specifically, it was idling in my driveway at less than 1000 RPM. It was probably 800 or something. Dunno if that is bad or not. Anyway imma go check the manual.