2008 Yukon gas tank issue.

[olliec420]

A lot of good info here. I too am having intermittent issues with filling tank and rough idle. No codes. Sometimes feels like its a bit down on power and idles rougher than I'd like. Some times it feels great and fills fine! Watched the videos posted here. I have no plans on getting another car and just rebuilt the trans in this thing. Trying to get it dialed in. Whats to say I just replace the canister and solenoids? Theyre not too expensive. (to be honest I kinda like shooting the parts cannon at it, Ive replaced a lot so far) Oh and Im guilty of overfilling, just learned that was bad here.

 

[Fless]

If you're going to replace all those things, then while it's apart take a little time to blow some air through the lines. Not a lot of pressure, just enough to be sure the lines are clear.

 

[Sam Harris]

If you're going to replace all those things, then while it's apart take a little time to blow some air through the lines. Not a lot of pressure, just enough to be sure the lines are clear.

Agree. Or you can replace the lines as well.. but they’re a little spendy.

 

[olliec420]

Agree. Or you can replace the lines as well.. but they’re a little spendy.

You talking about the lines included with the Vent Valve Assembly or different lines?

More Information for GM GENUINE 23481275

More Information for GM GENUINE 215464

These are the two things I was planning to order.

 

[Sam Harris]

I think that’s it. Never done that job myself, but when I looked up all the parts a while back they were pretty expensive.

 

[olliec420]

Simplify it like this: The tank needs to vent, and it vents into the charcoal ("EVAP") canister. The EVAP canister vents into the engine. Find out why the tank isn't venting. A quick test is to disconnect the largest hose on the canister. I think it's the center one. If you can fill up with no problems, then the canister is clogged. If the problem persists, the issue is before the canister, so in that hose or the tank itself.

So I did the disconnect and tried to fill up. I am still unable to fill. The filler tube fills up and then the gas pump shuts off. I can head the gas running down in the tank and air coming from the breather tube that vents in to the filler tube. Obviously not supplying enough air to make up for the fluid coming in. Whats the bad news? I just rebuilt the trans on this thing and have replaced a lot of parts in the last year. Im starting to get a lil annoyed. I wouldn't mind just throwing on a new canister and valve but this makes me think its a problem in the tank.

 

[theo robertson]

I had the same problem. I changed the canister and the valve problem solved.

 

[Geotrash]

So I did the disconnect and tried to fill up. I am still unable to fill. The filler tube fills up and then the gas pump shuts off. I can head the gas running down in the tank and air coming from the breather tube that vents in to the filler tube. Obviously not supplying enough air to make up for the fluid coming in. Whats the bad news? I just rebuilt the trans on this thing and have replaced a lot of parts in the last year. Im starting to get a lil annoyed. I wouldn't mind just throwing on a new canister and valve but this makes me think its a problem in the tank.

It's possible for the pellets to make their way into the lines in the tank and create a blockage. Some folks have had to drop their tank to get the lines fully cleaned out.

 

[Fless]

So I did the disconnect and tried to fill up. I am still unable to fill. The filler tube fills up and then the gas pump shuts off. I can head the gas running down in the tank and air coming from the breather tube that vents in to the filler tube. Obviously not supplying enough air to make up for the fluid coming in. Whats the bad news? I just rebuilt the trans on this thing and have replaced a lot of parts in the last year. Im starting to get a lil annoyed. I wouldn't mind just throwing on a new canister and valve but this makes me think its a problem in the tank.

I would clarify that the canister vents to the engine only when a purge event is taking place. And that's the "fume" or dirty side of the canister. The clean side vents through the vent valve (when open).

The tank fumes vent to the canister, and it in turn vents cleaned air while filling the tank, so long as the key is in the engine off position.

You likely have a partially blocked line from the tank to the canister, or the canister is blocked. If I understand it correctly, you already disconnected the line from the tank that connects to the canister, so suspect that line.

 

[Geotrash]

I would clarify that the canister vents to the engine only when a purge event is taking place. And that's the "fume" or dirty side of the canister. The clean side vents through the vent valve (when open).

The tank fumes vent to the canister, and it in turn vents cleaned air while filling the tank, so long as the key is in the engine off position.

You likely have a partially blocked line from the tank to the canister, or the canister is blocked. If I understand it correctly, you already disconnected the line from the tank that connects to the canister, so suspect that line.

All true. My hypothesis is that the pellets end up in the vent line in the tank through gravity because the canister sits higher than the top of the tank. And when they get in there, they bind together to create a plug in the vent line.