Gas Leak at Altitude

[Ed B]

I need some help to diagnose an issue I had this weekend (2004 LX470). I did a trip to the Eastern Sierra's. Topped off my tank in Bishop which sits at 4100 feet. I then drove into the mountains. At approximately 10,000 feet altitude I heard a noise coming from the back of the car. I stopped and found the noise was air and gas pouring out from the gas cap. I tried to tighten the cap but it was tight. I then loosened the cap a bit and gas really started to pour out so I tightened it back down. I continued to drive so I wasn't creating a puddle of gas under my car and the leak eventually stopped. I estimate I lost approximately 10 gallons of gas. Obviously altitude related but we routinely have trips posted at similar altitude, with this issue not mentioned, so I am thinking some type of venting issue. Any ideas on where to start checking?

Thanks

 

[MANUCHAO]

Fuel canister might be clugged?

 

[GeoRoss]

You had boiling gas. It is pretty common in the FZJ80 series, I don't know how common it is in the 100/470 series. As previously posted check your EVAC system. Could be the charcoal canister has failed or the VSV associated with the EVAC system.

 

[LexusAllTerrain]

Fuel canister might be clugged?

X2

 

[Ed B]

Thanks for the replies so far. Additional research also leads me to the fuel canister but there has normally been a corresponding check engine light with a code being displayed. I have none of that and otherwise the car is running great. Am still researching before I take it in Thanks again for the responses.

 

[LexusAllTerrain]

Thanks for the replies so far. Additional research also leads me to the fuel canister but there has normally been a corresponding check engine light with a code being displayed. I have none of that and otherwise the car is running great. Am still researching before I take it in Thanks again for the responses.

No need to take to dealer, how many miles on vehicle, if you are over 100k just replace, it is an easy fix, also check your return lines before hand just to be sure is not your canister!

 

[BruiserCruiser]

I have the same exact issue when going into high altitudes, spewing fumes and fuel droplets from the cap when I open up the cap a ton of pressure is in there. I was wondering if it was the charcoal canister also? I don't have a check engine light either by the way.

 

[LexusAllTerrain]

I have the same exact issue when going into high altitudes, spewing fumes and fuel droplets from the cap when I open up the cap a ton of pressure is in there. I was wondering if it was the charcoal canister also? I don't have a check engine light either by the way.

98.5% sure is Canister!

 

[PabloVTA]

http://forum.ih8mud.com/threads/charcoal-canister-great-option.412261/

 

[Ed B]

Thanks for the link. For clarification mine is a 2004 with 105,000. miles.

 

[tienckb]

2002 LX here. Exact symptom filled up at Bishop climbing to Coyotes Flat. 95 F weather temp, gas shot out. No codes thrown. Rig still runs perfect but will replace canister. Mine had 150k on clock.


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[F5driver]

Mine has done this inconsistently for years. No codes and sometimes it's a long time between episodes.

 

[Tennmogger]

The low Reid vapor pressure gas we get these days will boil at increased altitude, especially if that happens to be older gas of winter blend (with more high volatiles). Had that happen all the time in the mountains above Denver. I cut my gas with 10 to 20 percent Diesel and that worked great, ha ha (in a gas 404 Unimog that will burn anything).

Modern vehicles get around the problem with pressurized tanks and in-tank pumps.

 

[LexusAllTerrain]

Thanks for the link. For clarification mine is a 2004 with 105,000. miles.

Time for canister!

 

[gsdog2]

I changed canisters per the former IH8MUD thread and have no pressure blasting out of my tank at my lower altitudes around town and through the deserts like I once had with the old oem canister. Just got back from the Silverton, Colorado area and through the high passes (10,000'+) I again smelled fuel and had pressure and fuel coming out from the cap. No performance loss. I guess it's just the way it is.