I ride a 2002 Blazer and lost my gas cap a couple weeks ago and have beenprocrastinating on getting a new one. The last couple of days I've had problems pumping gas at some pumps. None of the gas I pump goes into the tank. It just overflows as if it was full. Will not have a cap cause something like this?

 

does the fill nozzle go all the way into the tank? No cap could cause rust or something to jam the little check valve at the top of the filler neck

 

yea it does. i'm able to flip in open all the way. maybe something got inside?

 

I would start with checking the area the gas is coming out of, then check hose connections.

 

Sounds like something is stuck in the filler tube. Can you see down in there with a flashlight?
Maybe try a straightened out coat hanger with a little hook in the end, otherwise you might have to remove the filler tube.

You should have a gas cap on to keep the pressure in the system. You have probably already seen the check engine light on and set an emission code, probably a P0400

 

Hmmm, this is an interesting dilemma. I've taken apart my gas tank and filler pipe and I did notice that there was a check ball that is trapped in a cage in the filler pipe, just above the point where the rubber connector connects the filler pipe to the tank. My best guess is that this ball in cage arrangement prevents your gas tank from being siphoned, as well as, the ball would block the gas from spilling out the filler tube in the event of a rollver with the vehicle ending up on its roof. Anyway, I wonder if it's possible that the ball has somehow lodged up into the cage where it won't let any gas INTO the tank. Hmmmmm!

 

maybe try putting some fuel treatment/cleaner down there to try to clean it up and free up any seized parts.