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Gas shooting from Filler Neck

Posted: Sun Jul 18, 2010 6:30 pm
by Rusgreim
I am posting this thread after the fact so any future users can search and hopefully find the solution to their problem.

A few weeks ago, after throwing a code for "Check Gas Cap" whch has been happening inconsistantly for a few years, despite my replacing the gas cap and cleaning the filler neck, I went to fill the car with gas.

After putting the nozzle in the car and beginning pumping after a few seconds, the pump shut off, and gas spewed out of the filler neck on the car and the ground. I figured it was a fluke and began filling again. The same results occured. Thinking it was a bad pump, I set it at its lowest setting, and allowed it to fill to a half tank and went on my way.

The same thing happened 2 fill-ups later.

The kicker was this past friday when, while driving between destinations, the car began to idle terribly roughly and threw a P305 Cylinder 5 Lean code.

After seeing a movie, the car still ran rough, UNTIL I opened the fuel cap to pump gas and it literally drew air into the tank for 10 seconds after the cap was removed. From the gas station home, it ran fine, and that when I knew it had to be an emissions vent.

I replaced both the forward and the rear vent, though the pumping gas issue was not resolved until I replaced the rear. When I went to replace the rear I could see that despite being half full of gas, the fuel tank had actually been drawn up away from the supports as the fuel pump created a vacuum inside the tank which could not be equalized due to the faulty evap solenoid.

The car is running fine now and the tank is staying where it is supposed to. Hesitation, stuttering and a few other issues I had attributed to an aging engine and bad plugs has also improved.

I hope putting this experience in writing helps some other member, somewhere down the road.

Re: Gas shooting from Filler Neck

Posted: Sun Jul 18, 2010 9:05 pm
by Archon
Than you for reporting that. I'm sure that it will be useful information.

Re: Gas shooting from Filler Neck

Posted: Sun Jan 01, 2012 11:21 am
by Ryan from Ohio
I just picked up a 2000 SLE with this same gas shooting issue. The seller warned me of it.

He told me it was just a check valve in the filler neck.

I just wrenched on the car a bit. Its a new filler neck! So I find it hard to believe its the check valve in it. Hell its got new stickers and such on it, cant be very old- 2-3K miles if.

I didnt notice any huge gasps of air when I pulled the fuel cap off.

Any ideas? Just clear the filler neck and try?

Re: Gas shooting from Filler Neck

Posted: Sun Jan 01, 2012 6:12 pm
by repinS
Hi Ryan,

This is an old post from 2010. Could you please continue here: http://www.pontiacbonnevilleclub.com/fo ... 18&t=30221