Gas tank venting upon opening cap.

[TomEf]

Definitely had some vapor venting to the point of dripping below the fuel door on Wednesday. Full tank, pretty warm, pretty high elevation, pretty choppy trail. Could smell gas from the front and while stopped. No codes, no rough motor, no symptoms.

 

[LvCruiserNewb]

The wife had the CEL and visit dealer message show up driving on the highway here in Vegas the other day. Stock 2018. Was 2 miles from thr dealer at the time. Took it in and made the service advisor read the codes even though all the techs were gone. P0441 and I can't remember the other one. Maybe P0456. They smelled gas when she pulled they said and checked the gas cap. It wasn't loose but they took it off and put it back on and then cleared the codes and they haven't come back yet after 100 or so miles. So hoping it was just the excessive temps and venting from the gas cap. I presume if it keeps coming back we need to get them to check the charcoal canister to make sure its not bad?

 

[mep1811]

I did have the charcoal filter replaced last year.

 

[grinchy]

@mep1811 there is a dedicated vent line on the main tank which runs up to the filler location, it is 6mm. With the cap off that line should see atmosphere and there would be plenty of available flow to prevent back pressure. It that line got clogged you’d see fill symptoms like this. I believe it has a rollover valve on it too, which could be an (unlikely) source of failure. That valve is not serviceable without dropping the tank.
The vent line has a two sided finger pinch pull hard clamp on it near the fuel tank at the crossmember (bottom of the filler hardline). It is hard to remove but doable. I suggest removing this clamp and fishing the vent line for debris. A 10 minute job plus however long it takes to get the damn clamp off.

 

[linuxgod]

What time of year for that 2017 Moab trip?

Early August. The dumbest time to go.
I’m going back this year same time...

 

[TeCKis300]

No issue with boiling gas or venting. I still have to dribble gas into the the main tank. The aux tank I can set the nozzle and it will fill without issue.

I think it's a few things going on exacerbating things. Your getting a bit of the Moab fuel gassing off, but the root issue is what I linked earlier with the LRA vent. When I was having issues, it wasn't always consistent because a part of it was gas station pump sensitivity.

The LRA vent breather from the charcoal canister is normally open when the car is driving or stopped and filling gas. It only closes to self test in the middle of the night.

Problem when it is plugged with silt and dirt is that the tank can't equalize or vent when running. Also a problem to fueling as again the tank can't vent to fill.

Fix the filter and change it with a large diameter vent line and all should be better.

 

[mudtracker]

Does anyone have a confirmed solution?
I just returned from Death Valley and experience the following

My problem only occurred when driving on steep climbs at about 5k feet elevation on dirt with temps about 110F
I never had issues on pavement

initial climb I smelled some gas fumes and heard the gas cap leaking so I turned it a little to release pressure and it started spraying fuel out which sounds like the Boiling fuel problem

later in the trip I would smell fuel in my cabin when running recycled air I opened the windows and it got really bad
I tried venting the gas cap but it had no pressure like the day before

next day drove on dirt at elevation temps in the 80s and not fumes
Afternoon did a climb and fumes returned
Checked gas cap but no built up pressure

Drove home to San Diego 106F and no issues

Looking for any Recommendations
Wondering if I should start by replacing charcoal canister
Or just use 91 octane on future trips
I wonder why I had high pressure first day at the cap but no pressure the other days but still had very bad gas fumes

thanks