Hi Don, that's good news (if it holds).
Speculating about how this could be happening, I realize I really don't understand how the Evap system works, especially all the parts on the gas tank that come before the Canister.
Here's a picture of a Eurovan fuel tank with all the evap hoses attached. ?
Don (and others) are saying that a problem with #3 (Breather Valve) could cause fumes to build up. ?This would make sense, but only if the 3,4,5,6 pathway is the only way for fumes to get to the canister.
However, there appears to be another pathway (9, 10, 11, 12, 7).
Could we be having a situation where both pathways are blocked?
Please help me ID these parts:
1. tank vent to breather bottle
2. Breather Bottle
3. is this the Breather Valve (?)
4. is this the Rollover valve (?)
5. ? is this tube normally open or closed?
6. is this the tube that lets you see and drain liquid gasoline?
7. Is this a valve? or just a T-connetor?
8. check valve?
9. another vent?
10. yet another vent or part? ?One side looks open to the atmosphere - is this an overpressure release? ?Perhaps where our fumes are coming from?
11. Mystery part - seems to take inlets from #9 and #10 ?What's in the box?
12. is this tube normally open?
Source:?
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On May 4, 2023, at 3:41 PM, Don Daynes <ddaynes@...> wrote:
Back in digest #712 Macon Cowles posted a great compilation of many people's experience with gas fumes, gurgling, and gas tank pressure when hot, especially at altitude.
The one that caught my eye was this excerpt from Gary Lewis:
I had a the same issue. My issue was pressure buildup in the tank when I removed the cap just as you stated. I could smell gas at times before removing the cap. It turns out that there is a small valve that gets pushed in when the gas cap is inserted. The gas vapors are then released into the charcoal canister etc. All i had to do is carefully bend the flat metal v shaped valve out a bit so when the gas cap was inserted the valve would open into the line and release the tank pressure. It's on the left inside. Hope that makes sense.
This easy repair "may" have fixed mine. I will withhold final judgment until I take the van up my problem road. This past weekend I took the van up to Yosemite before the park was closed due to flooding. During the trip up the mountain the ambient temp was not that hot but I was still surprised that when I stopped there were no gas fumes or pressure in the tank. The trip home was unseasonably warm through the central valley and I saw 210 degree engine temps going up the Grapevine. Again, after stopping at the first rest stop, there were no fumes gurgling, or tank pressure.?
My valve actuator is at the top of the filler not the left as described by Gary. The material is very springy and hard to bend. My efforts were to 'influence' the actuator closer to the center and to pull it out toward the camera in this photo. Think about? insuring the gas cap makes contact and fully opens whatever valving is going on inside as I was unable to figure out exactly what is was actually doing.
Fingers crossed.
