Back in January I tried pumping gas and it got 48 cents and spit it back out..the gas laid up on top (where you put the nozzle)...the fuel pump was also whining...the fuel pump ended up stranding me and I replaced it along with the check valve...This was in March...the fuel pump again now is whining after driving a good while (I deliver the mail)...and again I tried putting gas in and got 78 cents in...my mechanic said try running it with the cap off and see if it sucks the gas that was laying on top outside down into the tank...didnt' work...I put the gas cap back on..(truck still running) went in and paid for my 78 cents of gas...came back out and took the cap back off to see if it went down and gas came gushing out of it. Previously a couple weeks earlier my mechanic tested the pressure on the new fuel pump because of the whining and said it was holding too much pressure but didn't know why. When this latest incident happened with the gas gushing out...he "air" blew out a container up underneath my truck around the tank and this enabled me to put gas in...however it kept shutting off every 3 seconds or a little over a 10th of a gal ..at a time which at this rate takes me 15 minutes to fill up my tank...thinking some kind of venting problem but stumped...can anybody help please? Thank you for your time.

 

There's a rollerover stop valve in the intermediate filler tube over the axle. Shoould be a half hour job on a hoist.

 

Sounds like your charcoal canister is full of gas. When the fumes have nowhere to go, everything backs up into the filler neck, for lack of a better explanation. Then you can't pump anything in.

When you could pump gas in easily, do you try to top off the tank with the most you can fit in there? If so, that's your problem. When you fill up normally, stop pumping after the first click. Cramming as much gas as possible into the tank is one cause for the charcoal canister filling with gas. It has nowhere else to go because the tank is full already.

 

I would have suggested the vent solenoid - rear, end of tube attached to canister - except for the gas 'lying there.'. Still could be I guess.
When you take off cap does air rush out, then replace vent valve for sure.
Think your mech needs to do a heath check of all the vent plumbing in back.
Is your SES light on?

 

ok just replaced both check valves and the charcoal filter...still shuts off every 3 seconds trying to pump gas into it ...when I first start pumping the gas it will actually go for about 10 seconds...but then you can actually "hear" it filling up and stops like it's full ...then if I pump it super slow (it literally takes me 15 minutes to put 16 gals in my tank) I can get the gas in but as soon as I try pumping it a little faster I "hear" it filling up again and it shuts right off. Also I can really smell gas when my blazer is parked..I first thought that was from the charcoal filter being so saturated (which it was) but not sure now...I just got my blazer back yesterday and was excited because I thought it was fixed but found out real quick that it wasn't when I went to the gas station ...any other suggestions? my mechanic is stumped ...thanks everyone for your help I really do appreciate it!

 

Have you tried blowing air through all of the lines to make surer that none of them are plugged our collapsed? How about checking the vent line on the filter hose itself (the smaller line that runs along side the large line)?

Beyond that, I know this topic has been discussed a few times before.