Trouble filling up the gas tank

[S33k3r]

Do any of you guys know if this problem also applies to the NNBS Suburbans?

I’ve got an ‘07 2500 (6.0 LY6) that I think is stuck with the same issue. I just went to fill it up for the first time today and found that despite the gauge showing empty, it wouldn’t take more than 31 gallons AND fuel came flowing back out the filler before the gas pump shut off the first time.

Since the 2500 has the 6 gallon aux tank, I’m guessing I’ve got a venting problem somewhere that’s causing the aux tank to not fill and/or the main tank to not vent properly while filling and shut off early. No CEL or any other problems though.

Is it possible that your gas gauge is wrong?

 

[treehan77]

Even if gauge is wrong, it shouldn’t spurt gas out before clicking off the tank...

 

[S33k3r]

Even if gauge is wrong, it shouldn’t spurt gas out before clicking off the tank...

Fair enough, sorry. Was just hoping for the best.

 

[stubbs]

Fair enough, sorry. Was just hoping for the best.

Yeah, it'd be nice if it was just a gauge thing but I doubt it. The 900 platform seems to have a lot fewer of those issues from what I've read, and it was really odd that fuel came spilling out before the pump shut off! I think I'll have to go pull the evap lines off and see how much charcoal comes raining down on me. Fortunately the parts don't seem to expensive, RockAuto lists the valves and canister for a total of $140 or so.

 

[treehan77]

I think this can happen to just about any car of you keep putting in ore gas after it clicks, fouling the canister. Just let it stop and be done.

 

[Tony V]

If you have tried all of the usual recommendations and still have a problem with the pump shutting off while fueling, please see the attached PDF. My charcoal canister became compromised and leaked, this is how I fixed it.

Thank you so much for this!!! Mine was not a carbon filter failure but rather a bunch of varnish looking goop in the tank vent line from all the high quality gas these days. Blew it out and flushed with some brake clean, no more issues at the gas pump. Nice to find a dedicated forum that isn't on failbook, thanks again!

 

[JMV_05yukonSLE]

Quick question. If you did take it to a mechanic to replace Evap system and lines, etc, what would be an approximate cost?

I've got my mechanic working on this exact issue now in my 05 Yukon. I've replaced the fuel pump, evap, charcoal canister, and tank. My mechanic bought the charcoal canister at GM - $240. I bought the fuel pump and evap from a NAPA where I get a discount - $270. The gas tank came from a local scrap yard - $90. I've paid my mechanic $350 in labor so far, and it'll probably be a couple hundred more by the time I pick it up today, if it's finally fixed. I'll probably spend around $1100. I could have gotten that charcoal canister for a lot cheaper after market, but I'm in a hurry. I'm not mechanically savvy, but I am capable, and with the help of this thread and some proper tools I could have done this myself. It's just a time issue.

 

[Steve Davis]

JMV_05yukonS What was the eventual solution? I'm having this problem with my 2009 Tahoe and have replaced everything but the tank. It's not throwing any codes and I see the tank inlet has a check valve or rollover valve, and at this point I'm thinking of knocking that thing into the tank and see if that solves the issue.​

 

[Bruce0429]

To bring an old thread back to life, ive got same problem as everyone else....cant fill tank and have replaced everything. Im about to follow Roosters advice on clearing the tank vent line. But before i do, I was wondering if I blow compressed air into the vent line, can it push the pellets into my fuel tank and will that screw anything up, with of course having the gas cap off so I dont overpressure tank?

BTW, this is a major PITA!!!

Also, FYI, I tried using my leaf blower to apply air pressure through the gas cap. Blew for 10 to 15 seconds multiple times with the vent line disconnected. After turning off blower, could hear tank breathing (venting) back out of the fuel filler tube. I had put cotton glove over the vent line to see if anything was coming out.......nada. Multiple reasons why that may not have worked, including no seal and maybe not enough pressure.

 

[S33k3r]

There is a purge solenoid in the engine bay. There is a charcoal canister near the gas tank, underneath the chassis. There are vent lines, and there is a gas cap. Most likely, as you surmise, you have charcoal pellets in the vent lines; and, unless you are disconnected from the gas tank, yes you can blow them into the tank. If that is the case, make sure you replace the charcoal canister, too. If you can afford it, in terms of either time or money -- or both! -- I suggest replacing the lines. Then you don't have to worry about pellets going anywhere else. But that is my opinion. It may not be good sense.