Gasoline Leak Help

[jspaeth]

Hey, I filled up wit gas today and smelled gas like 2 minutes after leaving...the guy topped it off, but only by like 25 cents (insiginificant amount)

I pull over into a parking lot to get something, come out, and there is a small puddle of gasoline under the car (right under the tank)

Now, I a have had this happen before, and it was one of the fuel lines coming off the pump had come all the way off....

So I pop the access lid thingy off, and sure enough, all of the lines are fine, but I can see a small pool of gas on top of the part where the pump goes down.

The problem is, I dried it all out, and when the gasoline came back, it definitely wasn't coming out of any of the connections from nipples-->hoses...it seemed to be just "bubbling" up from around the edge of the cap.

I got home, let the car idle, and now, no fuel on the ground, so I am guessing it was because the gases was all the way up to the top......


Could I have a bad "fuel pump gasket".....this seems like it might be the problem, since the bubbling out of the gas stopped after I drove a bit. Also, if this gasket is slightly bad, would that completely inhibit my ability to build proper fuel pressure?

Thanks

[johngriff]

There are a few parts that may be failing in your fuel system.

There is a relief breather that should let air out so it does not over pressurize. But if you top the tank off too much, or the breather is clogged/broken it will not work.

The "gasket" you are speaking of is a large black rubber o ring that sits on the bottom of the "sending unit hat" against the fuel tank. This is where you are seeing fuel seep out from. More than likely it is bad, because of a fuel pump repair, and not using the OEM o ring, or reusing the stock o ring.

I am yet to find an identical oring to fit the tank, so i happily pay the $10 at the dealership for a new o-ring everytime the sending unit comes off. Because it is rubber, once it sees fuel vapor it expands and refuses to seal correctly.

Cliffnotes: Go to dealer, buy new o ring, replace.

[jspaeth]

Thanks for the fast reply.....this seems to make sense, as this would cause it only to leak if the gas is ALL the way up....

Also, by any chance do you know if having this type of leak (not a GAPING hole) causes major problems with supplying fuel to the engine at proper pressure.....in other words, can the fuel system raise the pumping quickly enough to keep up with the demand asked for by the ECU

[johngriff]

low fuel pressure, overly hot pump causing premature failure, and extremely unsafe by constantly mixing fresh oxygen in with the tank, turning your gas tank into a BOMB if you get rear ended.

[Wahl 136]

I had it happen to me before turns out the gasket was bad. Quick fix and no problems since.

[jspaeth]

alright thanks also, no oxygen will get into the tank, as it is constantly under pressure greater than atmostpheric....

but good try with the explosion thing

[johngriff]

i know, i know, a little bit of fear every now and then isnt all bad.

[jspaeth]

hahaha! if only i wasn't a chemical engineer, mayb you coulda had me there

thanks again for the help bro