Has anyone ever considered something like this?
Amazon.com: Flex-a-lite 4136 Fuel Cooler - 4,500 GVW: Automotive
Amazon.com: Flex-a-lite 4136 Fuel Cooler - 4,500 GVW: Automotive
Excessive fuel tank pressure
- Thread starter MaddBaggins
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FWIW, I always did a lot of high-altitude driving when I lived in CO; always had that smell. Where I am now at about 1000-2000 feet I rarely get it if ever, even in 115F+.
Driving to the top of Mount Evans (14k+') however can make the 80 smell like a gasoline evaporation factory.
Driving to the top of Mount Evans (14k+') however can make the 80 smell like a gasoline evaporation factory.
Funny, I was just thinking back to my drag racing days about something similar.
On my old drag car, I had a Folger's can that I coiled up 6 feet of aluminum fuel line in. I would then pack the can with dry ice for race night. It would cool the fuel as it came from the pump just before the carb. The thought is that you get a more dense charge and more power. I have been considering building something similar for the return line to troubleshoot this issue.
Dave
I suppose part of the problem is we don't know what's going on in there. I wonder how difficult it'd be to tap a temp gauge into the fuel line to measure the return fuel temperature.
It looks like there are some vehicles that have a fuel temp sensor OEM, and some heavy equipment that does, but I'm not seeing much else. I would think that you can't just slap any old temp sensor in there since fuel can be corrosive.
It looks like there are some vehicles that have a fuel temp sensor OEM, and some heavy equipment that does, but I'm not seeing much else. I would think that you can't just slap any old temp sensor in there since fuel can be corrosive.
I can use my IR thermometer on the line at a few different points. That would get us close to the actual fuel temperature.
Better than nothing, but difficult to do while driving.
Unless you remove the hood and hang out the window Hollywood action style...
Better than nothing, but difficult to do while driving.
Unless you remove the hood and hang out the window Hollywood action style...
I suppose to check it while driving, I could just tape a J thermocouple to the line and take the readings from my Fluke model 52 Digital thermometer. I have ways to figure this out....
- Thread starter
- #149
I'm thinking of opening the tank and measuring the gas temp in the tank. I will do this on saturday when my rig has been sitting in the sun all day. No driving, just a "cold" measurement to see my starting temp before I even fire her up.
I took one of my temp sensors and zip tied it against the return fuel line. Unfortunately I didn't get a temp higher than the engine bay temp. I think the engine bay temp swamped the sensor.
I'm not sure if measuring there will be accurate enough, or it could be my return fuel line is just not any warmer than the engine bay temps. But my guess is that the fuel line is too good an insulator.
I'm not sure if measuring there will be accurate enough, or it could be my return fuel line is just not any warmer than the engine bay temps. But my guess is that the fuel line is too good an insulator.
Another Tucson victim of the fuel vapor phenomenon. I had noticed it on a couple of occasions before, but the trip up Mt. Lemon on Saturday really seems to have exacerbated it. The gas smell was pretty strong and lasted quite a while. I thought about venting the cap, but visions of another "Aspen" fire made me reconsider.
I have made it a point to not top-off when filling, but I've not done any other troubleshooting. I'm heading to Bisbee this weekend, so I'm going to check the temp in the gas tank before leaving and when we arrive, and see what (if any) difference there is.
There has to be an answer, right?
I have made it a point to not top-off when filling, but I've not done any other troubleshooting. I'm heading to Bisbee this weekend, so I'm going to check the temp in the gas tank before leaving and when we arrive, and see what (if any) difference there is.
There has to be an answer, right?
- Thread starter
- #152
Yeah Rex, my research the last few years has lead me to believe that the boiling point of gas these days is lower than it used to be. Couple that with our very hot, high altitude climate and evap parts that are getting old and you have a scenario where the system can't handle the overload of fuel vapor. I've been smelling it from lots of vehicles around here, it's not just our old cruisers.
I think the solution is going to be insulating many of the fuel system components and exhaust to keep the fuel tank temp as low as can be.
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Well, I'll throw in my .02.
I've got a 97 SC'd with a Long Ranger tank and a (my understanding) non-emissions OEM dual filler neck.
This summer is the first (of 3 that I've owned this particular 80) that I noticed the fuel smell. The 1st time I noticed was on an extended trip to the Durange area. This required four very high altitude (my base altitude is ~8,000') passes.
My charcoal canister did not pass the FSM test. So I replaced with new from cdan.
With the new CC in place, the fuel smell is greatly reduced. If I had to unscientifically guess, I'd say 90%+.
However, the fuel smell that remains is eminating from the fuel filler area, and when I remove the gas cap I have found what I deem to be excessive venting. Especially considering the fact, that I've never owned a vehicle that vents for more than a couple seconds at most.
I have not tested the VSV or other valves associated with the system. However, considering that Romer and other folks with SC'd rigs at altitude with aux tanks and new(er) CCs are experiencing similar, I've come to the following conclusion.
Having an 80 that is SC'd with an aux tank and towing at altitude exasorbates the condition.
I'm looking forward to seeing what others come up with as a solution other tha the onset of fall and cooler temperatures...
I've got a 97 SC'd with a Long Ranger tank and a (my understanding) non-emissions OEM dual filler neck.
This summer is the first (of 3 that I've owned this particular 80) that I noticed the fuel smell. The 1st time I noticed was on an extended trip to the Durange area. This required four very high altitude (my base altitude is ~8,000') passes.
My charcoal canister did not pass the FSM test. So I replaced with new from cdan.
With the new CC in place, the fuel smell is greatly reduced. If I had to unscientifically guess, I'd say 90%+.
However, the fuel smell that remains is eminating from the fuel filler area, and when I remove the gas cap I have found what I deem to be excessive venting. Especially considering the fact, that I've never owned a vehicle that vents for more than a couple seconds at most.
I have not tested the VSV or other valves associated with the system. However, considering that Romer and other folks with SC'd rigs at altitude with aux tanks and new(er) CCs are experiencing similar, I've come to the following conclusion.
Having an 80 that is SC'd with an aux tank and towing at altitude exasorbates the condition.
I'm looking forward to seeing what others come up with as a solution other tha the onset of fall and cooler temperatures...
Another variable in your case is your large extra fuel capacity that exceeds the design limits of the evap system on the truck.
So to share my recent experiences.....
Over the weekend had a nice wheeling trip. Both my 80 and Toy350's 80 had issues with high fuel pressure in the tank.
On his, he noticed that when he bounced drivers side (that is drivers down, passenger up), gas was literally flinging out of the side of his truck. He stopped, tried to open the cap and got sprayed with fuel. So he barely cracked it and let the pressure release.
In my case, I noticed that when we stopped there was a little fuel around the fuel cover. Popped the cover, and fuel was (slowly) leaking out. Cracked it open to relieve the pressure, and problem solved.
In both cases I believe it was a combination of a rise in elevation and a hot day. It was over 90* ambient, and I know my engine compartment was over 160* (unfortunately the thermostat I'm using currently stops at 70* C, AC never cut out so I know I didn't get into an overheat situation). Normal running temps for me are 100*-125* F on the freeway, and 125*-140* F city (with ambient in the 80's to 90's).
Both Toy350 and my rig are pretty much stock for the fuel/etc side, neither of use has an aux tank or SC, and both have original CC canisters (which are probably plugged up).
I noticed my return line hoses were starting to develop cracks, so I think I'm gonna swap 'em out. I'll probably install one of the fuel coolers mentioned earlier in the thread at the same time.
Over the weekend had a nice wheeling trip. Both my 80 and Toy350's 80 had issues with high fuel pressure in the tank.
On his, he noticed that when he bounced drivers side (that is drivers down, passenger up), gas was literally flinging out of the side of his truck. He stopped, tried to open the cap and got sprayed with fuel. So he barely cracked it and let the pressure release.
In my case, I noticed that when we stopped there was a little fuel around the fuel cover. Popped the cover, and fuel was (slowly) leaking out. Cracked it open to relieve the pressure, and problem solved.
In both cases I believe it was a combination of a rise in elevation and a hot day. It was over 90* ambient, and I know my engine compartment was over 160* (unfortunately the thermostat I'm using currently stops at 70* C, AC never cut out so I know I didn't get into an overheat situation). Normal running temps for me are 100*-125* F on the freeway, and 125*-140* F city (with ambient in the 80's to 90's).
Both Toy350 and my rig are pretty much stock for the fuel/etc side, neither of use has an aux tank or SC, and both have original CC canisters (which are probably plugged up).
I noticed my return line hoses were starting to develop cracks, so I think I'm gonna swap 'em out. I'll probably install one of the fuel coolers mentioned earlier in the thread at the same time.
Another, so to share my experiences.....
Last week I spent all week in the Ouray/Silverton area (9000 to 12000 ft) with my 92 FJ80. Found excessive gas tank pressures at high altitudes. Here's my experiences;
After venting the tank by SLOWLY removing the gas cap, I could hear fuel boiling in the tank for several minutes. Upon trying to start the vehicle it acted like I just changed the fuel filter, very hard to start. I am now convinced that the fuel line (pressure side) is getting hot and boiling the fuel back into the tank. If I didn't open the cap to relieve the pressure, vehicle would start normally. Conclusion: Just as MaddBaggins mentions; "the boiling point of gas these days is lower than it used to be." and "I think the solution is going to be insulating many of the fuel system components and exhaust".
I will be specifically looking into insulating my fuel lines. FYI, vehicle is stock, 310K, with new blue fan clutch (soon to be modified), AC activated 12" pusher fan and hood vents.
Last week I spent all week in the Ouray/Silverton area (9000 to 12000 ft) with my 92 FJ80. Found excessive gas tank pressures at high altitudes. Here's my experiences;
After venting the tank by SLOWLY removing the gas cap, I could hear fuel boiling in the tank for several minutes. Upon trying to start the vehicle it acted like I just changed the fuel filter, very hard to start. I am now convinced that the fuel line (pressure side) is getting hot and boiling the fuel back into the tank. If I didn't open the cap to relieve the pressure, vehicle would start normally. Conclusion: Just as MaddBaggins mentions; "the boiling point of gas these days is lower than it used to be." and "I think the solution is going to be insulating many of the fuel system components and exhaust".
I will be specifically looking into insulating my fuel lines. FYI, vehicle is stock, 310K, with new blue fan clutch (soon to be modified), AC activated 12" pusher fan and hood vents.
My concern about insulation is that much of it can collect/absorb fuel, oil, etc. Say you get a small fuel leak, instead of just dripping down or evaporating, it'll collect and build. I've heard about way too many car fires from header/exhaust wrap doing exactly that.
Second Skin has their Firewall material, I think I'm going to order that and coat the charcoal canister with it, which would help significantly (I would think). Aside from that, I'm not sure of a good way to insulate the fuel lines. A fuel cooler would help a lot as well if there's a good way to mount it towards the front (maybe under the tranny cooler if there's room?).
I'm really convinced that the main root of the problem is the heat more so than the elevation (though lower boiling temps would make the problem worse). I was only at 3k feet this weekend, and had an elevation climb of maybe 2k feet, and still experienced the same problem (though not as bad).
Second Skin has their Firewall material, I think I'm going to order that and coat the charcoal canister with it, which would help significantly (I would think). Aside from that, I'm not sure of a good way to insulate the fuel lines. A fuel cooler would help a lot as well if there's a good way to mount it towards the front (maybe under the tranny cooler if there's room?).
I'm really convinced that the main root of the problem is the heat more so than the elevation (though lower boiling temps would make the problem worse). I was only at 3k feet this weekend, and had an elevation climb of maybe 2k feet, and still experienced the same problem (though not as bad).
Not sure if this has been mentioned yet but when the tank is 'venting' it is impossible to fill up. The excessive pressure kicks the pump off. I was up around 10,000 feet and tried to fill up (was at about 1/2 tank) and had to wait for the spewing vapors to stop until I could fill up. Gas system is all stock, new gas cap adds to the pressure because it doesn't leak. From an emissions viewpoint, the whole design is to prevent gas vapors from being released into the air. Last time I was in California they had silly things on the gas pumps to reduce vapors from being released when filling up. Based on my pressure, that has enough force to spray fuel in your eyes, the system is 'working'.
During heat and wheeling Only
Not sure if any more progress or solutions have been made on the issue. But I'll throw my experience together for a continuous log of the problem.
Well after a year I have experienced the same issue again. Strong smell of gas coming from hood. I removed the gas cap but this time it was more of a boiling sound and pressure that almost blew the gas cap out of my hand, actually spewed fuel out about 5 feet. This was the second time it has happened, first was last summer but not as bad. The only similar variables are hot day (90 + F), during wheeling off camber and climbing, 3/4 or less tank of fuel not topped off. Elevation was heavily in play yesterday 500 ft in San Diego up to 8,000 ft just south of Palm Spings up Toro Peak slow crawilng in low and locker at times. Last year it was from 500 ft to 4000 ft back down to sea level and was venting at sea level in the desert floor with only mild climbs but a lot of off camber. So not sure of elevation issue but it did vent more heavily this time at a higher elevation. I did notice that when we hit the peak we stopeed for lunch about an hour, went to vent the gas cap as a check and no pressure at all. The peak was noticably cooler with a breeeze. Checked again at home at 500 ', 80 F when filling up, no pressure at all and maybe a slight vacuum.
So the only consistent variables are temp, time of year and wheeling hard and maybe elevation. Since I had not experienced the venting and pressure issue any other time I can only conclude what others have. Gas blend, temp, time of year, elevation and sloshing around seems to cause the pressure problem. Duh, but is there a way to fix or prevent it?
Should I be worried or just chalk it up as a cruiser problem?
Have replaced all the small vacuum lines, vacuum modulator, checked the intake hard lines, replaced the lines to and from the CC, new PCV valve and hose, cleaned the throttle body and have no codes. Have not replaced the main line vacuum line under the the intake to the T fitting one person earlier suggesed or checked any of the return lines to the tank. Now considering the CC replacement as a well to help but not sure.
Not sure if any more progress or solutions have been made on the issue. But I'll throw my experience together for a continuous log of the problem.
Well after a year I have experienced the same issue again. Strong smell of gas coming from hood. I removed the gas cap but this time it was more of a boiling sound and pressure that almost blew the gas cap out of my hand, actually spewed fuel out about 5 feet. This was the second time it has happened, first was last summer but not as bad. The only similar variables are hot day (90 + F), during wheeling off camber and climbing, 3/4 or less tank of fuel not topped off. Elevation was heavily in play yesterday 500 ft in San Diego up to 8,000 ft just south of Palm Spings up Toro Peak slow crawilng in low and locker at times. Last year it was from 500 ft to 4000 ft back down to sea level and was venting at sea level in the desert floor with only mild climbs but a lot of off camber. So not sure of elevation issue but it did vent more heavily this time at a higher elevation. I did notice that when we hit the peak we stopeed for lunch about an hour, went to vent the gas cap as a check and no pressure at all. The peak was noticably cooler with a breeeze. Checked again at home at 500 ', 80 F when filling up, no pressure at all and maybe a slight vacuum.
So the only consistent variables are temp, time of year and wheeling hard and maybe elevation. Since I had not experienced the venting and pressure issue any other time I can only conclude what others have. Gas blend, temp, time of year, elevation and sloshing around seems to cause the pressure problem. Duh, but is there a way to fix or prevent it?
Should I be worried or just chalk it up as a cruiser problem?
Have replaced all the small vacuum lines, vacuum modulator, checked the intake hard lines, replaced the lines to and from the CC, new PCV valve and hose, cleaned the throttle body and have no codes. Have not replaced the main line vacuum line under the the intake to the T fitting one person earlier suggesed or checked any of the return lines to the tank. Now considering the CC replacement as a well to help but not sure.
That could explain my problem and Romer's problem (although IIRC his tank is an OEM aux tank),. However, obviously this is happening to a significant number of 80s and the only thing common I'm reading is altitude and heat.
Yesterday after driving back in 90-100 degree temps at altitudes of 7k-9k, I decided to check when I got back in the garage. The new CC is working better than the old as the fuel smell is no longer eminating from the engine bay. However, there still is a small gas smell coming from the fual filler neck. I popped off the gas cap, and it whooshed followed by starting to spit out fuel. I quickly put the cap back on and left it over night.
I did fuel up in Gypsum. Filling my main tank and putting ~20 gallons in the LR. I always put some extra when I go to Glenwood Springs or beyond as I'm saving ~$1 per gallon compared to local prices.