It spills out...duh.

 

I'm not playing your stupid game.

 

I'm not playing your stupid game.

Meaning you have no idea...
And no, it didn't spill...
"Intersting" head - Car still drives around...

 

 

Where the excess goes also depends on your locale's regulations of vapours. In my area it can be a waste of money.

 

If you "overfill" the tank while pumping, the excess gas is picked up by the gas pump and goes back into the gas station's tanks.

If you fill your car absolutely full, flooding the vapor collector in the car, the gas will expand in the tank and give you bad gas mileage. Then your muffler bearings explode.

So why are you posting this question if you know it already? I don't understand lol.

 

If you "overfill" the tank while pumping, the excess gas is picked up by the gas pump and goes back into the gas station's tanks.

False. If the pump could "suck back" excess fuel, that's a tremendous fire hazard. A small fire on the pavement could be drawn back down to the station's main tanks... instantly causing a really bad day for the fire department. There are check valves in the pump to prevent this.

The gas pump uses an ingeniously simple mechanical vacuum valve to shut off the pump when the gas level reaches near the end of the pump nozzle, but if you force the pump back on again, it absolutely will overflow the car's fill tube and spill over the side of your car. You can thank our good friend Bernoulli for this neat little valve.

 

I heard it goes back from whence it came... Oz.

 

NOS!

 

I guess if you have a faulty gasket on the hatch that you open to replace the pump that it could spill in the cabin of the car....but then you have other problems, one being that you have been sucking gas fumes in your ride and not fixing it.

 

The gas trickles back into the gas pump handle, where tiny elves live at exactly the halfway point. These elves thrive on incoming gasoline, whilst having no use for outgoing gasoline. Once the incoming gasoline gets to the tiny elves, they mate with the particles, creating Charlie Sheen.

 

lol

Last time, and only time, my tank got overfilled, the station attendant actually did it because the pump was malfunctioning - charging me without pumping any gas...he kept forcing the pump and eventually gas was coming out all over the ground and all over my car. My car didn't drive any differently for many years to come so not sure what happens other than a stinky mess.

 

lol
.... My car didn't drive any differently for many years to come so not sure what happens other than a stinky mess.

Was this a WRX? I'm asking this for a real reason...

 

It was a Plymouth Laser - 4 banger turbo.

 

OK, nobody knows?
But everybody knows nobody, so I guess for right now I'm nobody...
I was going to give rep to Rambo for best (if still wrong) answer, but the system won't let me: "you have to spread the love around..." or something to that effect.
Anyways, I had this effect: car started to run sickly and then a CEL "running too rich". My interpretation is that the fuel pressure regulation got effed up and delivered too high pressure, resulting in injectors dis-charging too much fuel. Car did run noticeable rich, smelled accordingly. After a while of driving around and everything seemed normal I got gutsy and reset the ECU. No ill effects whatsoever. So no more filling to "upper level lower lip"... my poor car was literally fed-up!

 

No, this doesn't make sense.

The fuel pressure regulator is a passive device: if the fuel pressure increases above 43 PSI, the excess pressure is routed back into the tank. By obvious nature, if you remove fuel to feed the injectors and the excess fuel is fed back through the return line to the tank, you'll always end up with less fuel in the tank then when you started (I wish this wasn't the case). Excess fuel is routed back through the return line with a pressure of at least 43 PSI. To cause back flow, you'd have to have at least 43 PSI of pressure from the fuel tank: this means either a 37.5 meter deep fuel tank or 43 PSI of vapor pressure. You'd have neither and you're grasping at straws.

 

Really? My 2002 has had gas spill out of the filler all over the side due to I'm guessing a faulty shut off valve in the filler gun. Had to stop it manually or it would have kept going. The attendant immediately put one of the out of order bags over it when I told him.

No effect on the car what so ever other than gas draining all over the side of the car and wheel. No CEL, No bogging, No smell or smoke. I do not have a wide band to monitor AFR though.

Could it be isolated to newer models?

 

Could certainly be. Could also be a mis-diagnosis on my part. This is just what I experienced. And I'm positive that the overfill lead to the symptoms I had. However, I've done same thing with virtually every car I've owned, never had this. But then again, I've also never had a car quite as new as this one. That's why I posted this whole thread, just to see if maybe someone had a good understanding of this vapor recovery and associated junk...

 

No stupid questions....

 

Only stupid questions are those nobody asked... And if you look further up - that's me...

 

I disagree. It's a very stupid question and isn't worded well and will receive slow feedback for the answer you're looking for. It's easy to ask a question to which you already know the answer because you know the answer you're looking for. But since it's not worded very well, it's probably not going to draw out the answer you already know. Since you left it so broadly worded, there are tons of variables that can easily lead to 100 different correct answers. So, yeah, pretty dumb if you ask me.

 

OK...

 

I mean, are you looking for the answer that if the tank is overfilled it wont allow the gas to expand? Or are you talking about flooding the emissions systems? What about cars that don't have modern emissions systems? If you're looking for a specific answer, you need to ask the right question. :alextrebek:

 

See, if I knew I wouldn't be asking.... I'm asking as stated, since I did overfill and my car got "sick" for a while. Not knowing anything about the vapor recovery and how it interacts with emissions and the rest of the fueling I was left with only guessing that it messed up the fuel pressure regulation. I was hoping someone would know and go "vapor lock increases pressure beyond what regulator can handle.." or whatever. I honestly don't know much about this. I have not had a vehicle with the "modern day" emissions, the newest I had before was a '96 JP GC with the v8. It had some exhaust return and cats. That's about it... Everything before that didn't even have cats or anything. I'm a bit old-school, even from before electronic ignition and fuel injection.

 

So, Zax, you think there shouldn't be any connection between overfill (even flooding the vapor recovery stuff) and fuel pressure at injectors? I'm not disputing you, just clarifying. It does make sense that the pressure regulator would just bleed off the excess thru the fuel return line. And regrettably the return is always somewhat less then the feed. Hence the need to fill up from time to time. I also don't think the tank and other components would care much for 43PSI, something would likely give. Any ideas what made my car sick? It does seem related to the fill level.

 

Here's a thought I had on my way home: The vapor tank is a charcoal container for all that I know (which isn't much...). This would have to be purged. I would guess that's done thru vacuum lines. Meaning the engine gets to "suck it up" with the intake. Would that fly as explanation?