2008 Yukon gas tank issue.

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Summer b

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I am unable to fill my gas tank. It pretty much overflows within seconds. this started a month or so ago with it just clicking off like it was full and its slowly progressed to almost unable to get a dollars worth in with a gas can! No rough idle no check engine light either. Any help would be greatly appreciated. 2008 Yukon 5.3 ltr
 

B-train

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Probably the purge solenoid under the hood by the intake. Do yourself a favor and buy only GM parts. Or, it could be the charcoal canister let loose and filled the lines with little pellets. Do you electrical tests first. You can also remove the solenoid and let it vent to atmosphere if you are mechanically inclined to do so, I'd just do the test on a cold engine.
 

Sam Harris

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Yup. The ventilation of the tank is either blocked (charcoal pellets in the lines) or one of the valves is not functioning. If you (or a previous owner) has a habit of filling past the point the pump shuts off while fueling, this will cause fuel to enter the charcoal canister, and eventually, the pellets make their way out the lines, blocking them off.
 

Fless

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The purge valve on the engine has nothing to do with filling the truck, so look to the rest of the evap system. A purge valve staying open (incorrectly) could cause a hard start after filling, due to fuel fumes being allowed to enter the intake manifold.

Fueling should be done with the truck engine off so the canister vent valve is open to, well, vent. If anything blocks the vent lines, then the fuel won't fill easily. Overfilling can flood the evap canister, block it, and loosen the charcoal bits to spread into the evap lines.

Lots of YouTube videos on evap system diagnostics. Search the forums here on TYF; if you need some links, yell!
 

89Suburban

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I would think a failed valve would trigger a CEL light but I could be wrong. When my rear vent hose/valve thing-a-ma-bob went bad it threw the CEL and stored a code.
 

MassHoe04

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I would think a failed valve would trigger a CEL light but I could be wrong. When my rear vent hose/valve thing-a-ma-bob went bad it threw the CEL and stored a code.
I got a code/CEL a few months back.

This is what I got when my purge valve was not working. I believe it was sticking in the open position and threw this code when it happened.

20211123_071347.jpg

I agree that issue on this thread is not a purge issue, but a vent issue. Vent tubes between the filler and the tank would be my first suspect to check out, then the charcoal canister followed by vent valve.
 
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Summer b

Summer b

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The purge valve on the engine has nothing to do with filling the truck, so look to the rest of the evap system. A purge valve staying open (incorrectly) could cause a hard start after filling, due to fuel fumes being allowed to enter the intake manifold.

Fueling should be done with the truck engine off so the canister vent valve is open to, well, vent. If anything blocks the vent lines, then the fuel won't fill easily. Overfilling can flood the evap canister, block it, and loosen the charcoal bits to spread into the evap lines.

Lots of YouTube videos on evap system diagnostics. Search the forums here on TYF; if you need some links, yell!
Yes please send me some links! Thanks!
 
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Summer b

Summer b

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I would think a failed valve would trigger a CEL light but I could be wrong. When my rear vent hose/valve thing-a-ma-bob went bad it threw the CEL and stored a code.
Only thing scanner said was routine maintenance almost due!!!
 

Fless

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Here are a few for starters:

The Car Doctor
Vent solenoid replacement

WatchWesWork
Evap canister testing (0:00-5:15 min, then 11:00-13:15)

1A Auto

I'm sure that Eric O at South Main Auto on YouTube has a few, too. Let's hope you don't have to blow out any lines, but that's also a possibility.
 

89Suburban

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Here are a few for starters:

The Car Doctor
Vent solenoid replacement

WatchWesWork
Evap canister testing (0:00-5:15 min, then 11:00-13:15)

1A Auto

I'm sure that Eric O at South Main Auto on YouTube has a few, too. Let's hope you don't have to blow out any lines, but that's also a possibility.


Love the Car Doc and 1A.
 

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