Dificult to fill gas tank.

[STX]

I have searched and found a little about purge valves and canisters but nothing specific to correct this issue.
I can barely fill the tank without the pump clicking off about 15 times. It is annoying. I have no codes or other issues but it does seem like an evap/venting issue since when I go really slow, it doesn't click the pump off as frequently.
I am not a fan of throwing parts at a repair so can anyone shed some light or share their experience with what to look for or what you did to correct this issue?
Thanks,
It's a 2009 Yukon XL 5.3 Flex with 86K.

I have a 2007 Yukon that has same issue. Replaced the carbon canister, evaporative solenoid and purge valve as per You Tube videos. Nothing worked. I dropped the fuel tank and flushed out the vent lines with compressed air. The carbon pellets had plugged all the vent lines causing the problem. Not a hard task. All is good now. Hope this helps. There is a You Tube video available. Good Luck.

 

[PatDTN]

Funny, I have problems from time to time and never thought it could be my truck. I just thought the pump was set up wrong. This place is useful.

 

[STX]

Yes fellers, if you have the fuel fillup problem you've probably contaminated the fuel vapor carbon canister by overfilling your tank. This causes "rat poop" type pellets to develop in your canister. (some You Tube videos are available) These pellets will eventually clog your vapor canister & fuel vent lines going to the tank. Drop the tank, use compressed air to blow out lines & replace the carbon canister ($99-$120). Upon removal you'll notice the pellets falling out of the carbon canister. A quick test would be to unplug one of the vent lines leading from the fiel tank to the canister. You'll see pellets fall out right away. If you don't replace the canister you'll end up with the same issue in a few months. Dust on the evap solenoid (unless really muddy) isn't too much of a problem but wouldn't hurt to change it ($28-$35).

 

[Scottydoggs]

Yes fellers, if you have the fuel fillup problem you've probably contaminated the fuel vapor carbon canister by overfilling your tank. This causes "rat poop" type pellets to develop in your canister. (some You Tube videos are available) These pellets will eventually clog your vapor canister & fuel vent lines going to the tank. Drop the tank, use compressed air to blow out lines & replace the carbon canister ($99-$120). Upon removal you'll notice the pellets falling out of the carbon canister. A quick test would be to unplug one of the vent lines leading from the fiel tank to the canister. You'll see pellets fall out right away. If you don't replace the canister you'll end up with the same issue in a few months. Dust on the evap solenoid (unless really muddy) isn't too much of a problem but wouldn't hurt to change it ($28-$35).

where your right about the pellets coming out, they are there from day one new, those are your charcoal pellets. they didnt form, they were there the whole time. once the canister tank fails the pellets come out and clog the hoses. now you dont have a vacuum release as you fill the tank, aka the tank cant vent out, thus shutting off the pump cause it thinks the tank is full.

 

[randeez]

Need to do this on mine...happens every few fill ups

 

[Tractoman]

So here is my update to this slow fill issue.
Friday I replaced the evap canister and evap vent solonoid. The truck already had the newly designed evap solonoid which relocates the solonoid and has the long tube for the air vent for the solonoid but I relaced it too. I used my shop vac to suck air on the vent lines from the tank and got no pellets at the canister connection and a few at the small tube going up to the filler pipe. Put it all back together and have been able to put gas in without holding the pump nozzle once from about 1/4 to a little over half and today to almost full. Different stations and pumps each time. I am not sure what the issue was but suspect the canister may have been ruined from overfilling and was waterlogged with gas so to speak or just clogged, but I could blow air easily through all the ports. It is amazing to be able to stick a pump in the fill tube, start it and walk away and have it flow at full speed. Took about an hour and a half, including lowering and re installing the spare. Pretty easy and well worth the effort.

 

[demo124]

2009 Yukon - I have replaced fuel pump, vapor canister, vapor canister vent solenoid. Still filling tank slowly. Is there anything else I can check?

 

[randeez]

did you "clear the lines" i think the granules from a bad canister break up and clog the lines. i didnt do mine when i swapped it, but it has been 20x better. i still come across a pump or two that will just kick off every few seconds i just hang the shit up and go somewhere else lol

 

[demo124]

I did everything mentioned above except blowing out the lines. Didn't know better when I had the tank dropped. Next time I will clear the lines. When replacing all of those parts, I didn't notice anything fall out of the lines.

 

[ivin74]

I did everything mentioned above except blowing out the lines. Didn't know better when I had the tank dropped. Next time I will clear the lines. When replacing all of those parts, I didn't notice anything fall out of the lines.

You need to blow the lines, that is the first thing anyone having this issue should do. If pellets come out replace the canister. Then start replacing the sensors if all else fails.

Every one usually starts throwing parts at it and ends up being plugged hoses.