Excessive fuel tank pressure (2 Viewers)

[ThomasMore66]

Mid 90's in Durango today. Drove from my house at 6950' to Lime Creek road ( 9600' or so) for a little lite 4-wheeling and hiking with my dogs. Up and back I smelled nothing off my truck with the ethanol free fill up. I'm thinking your congressmen are partially responsible. Ethanol is good for racing applications, but not for anything else. Ban ethanol!

 

[ThomasMore66]

I received my VC120, but the venting has been significantly reduced with the ethanol free gas. I'm thinking it is a charcoal issue, but that ethanol is bad for volatility.

 

[Jungle80farmer]

I'm happy to report my vc120 & new hoses has me 100% gas stink free! Mine was BAD. Best $60 I've ever spent.

 

[GeoRoss]

I have a spare OEM in the garage for when my original poops out.

 

[mjeckell]

Just installed a week ago the acdelco 215-153 and I have not had any pressure build up at gas cap since install. Install went fairly smooth as others have reported. I got a longer hose line to reach the factory air inlet. And bought a longer m6 bolt to accommodate the slightly larger canister. Just used the upper bracket.

 

[alia176]

If all is clear and you still are getting fuel smell check your fuel regulator as noted by @Dalton wyatt in post #290 above.

What is the logic behind the FPR failing and contributing to the excessive vapor pressure? If it's already been said, let me know which post # has this info.

 

[MaddBaggins]

Wow! I'm glad to see some activity on this old thread. My rig still smells like a whole of fuel every summer. I need to find where I left off in this thread and catch up. I can tell you that a replacement OEM CC and new lines have no effect on the summer gas smell. I dare not open my gas tank on hot days again, early morning only.

 

[MaddBaggins]

Never mind. The new fuel they sell us has some serious issues...

Thats exactly what mine did the one time I made the mistake of opening it.

 

[MaddBaggins]

Well, caught up from where I left off. This is still a very common problem for 90's and early 2000's vehicles here in Tucson. I'm still of a mind that the 10% ethanol fuel we get here is the culprit to these vehicles not designed for it. The only "non ethanol" gas to be had around here is too far away to be practical. Smell it very heavily from many vehicles when on top of the mountain, 7-9k' but pretty common around town also, 2000'+.

 

[jdayment]

Has anyone found one compatible with a 3FE I had the gas woosh syndrome and sprayed wd-40 in the inlet and outlet lines of my charcoal canister thinking it was a stuck check valve and that has stopped the woosh but I figure it is just a matter of time before I need to replace completely. The one used on the 1FZ does not fit in the 3FE location from what I could figure out.

 

[Twinair]

My thoughts are ethanol boils off at a much lower temp than gasoline and builds tank pressure beyond the evap system's ability to vent. Once tank pressure reaches a certain point ethanol gasses remain suspended in the gasoline until you remove the cap and release the pressure. Once pressure is released, the dissolved ethanol gas is released much like opening a bottle of soda. After reading this thread I'm going to run ethanol free where I can and see if my tank pressure decreases. I haven't had the smell of fuel or a whining from built up pressure, just more fuel tank pressure than I'm comfortable with when I remove the cap.

 

[Red Merle]

OK, I got my vc120 ready. Is there any value in replacing the lines from the tank and to the intake manifold? When I blow in the one to the tank with gas cap off, air goes through, but not really quickly, which could just be because of the length of the hose. Is there any harm in giving it a blast of air from my compressor?

 

[MaddBaggins]

OK, I got my vc120 ready. Is there any value in replacing the lines from the tank and to the intake manifold? When I blow in the one to the tank with gas cap off, air goes through, but not really quickly, which could just be because of the length of the hose. Is there any harm in giving it a blast of air from my compressor?

Use a low pressure if you're gonna do that. You won't need much, 2psi is more than enough.

 

[MaddBaggins]

My thoughts are ethanol boils off at a much lower temp than gasoline and builds tank pressure beyond the evap system's ability to vent. Once tank pressure reaches a certain point ethanol gasses remain suspended in the gasoline until you remove the cap and release the pressure. Once pressure is released, the dissolved ethanol gas is released much like opening a bottle of soda. After reading this thread I'm going to run ethanol free where I can and see if my tank pressure decreases. I haven't had the smell of fuel or a whining from built up pressure, just more fuel tank pressure than I'm comfortable with when I remove the cap.

I've yet to try the ethanol free test during summer. I'd have to drive over 100miles to get ethanol free. I don't usually take many trips when it's this hot. If we are road tripping it, we're probably in the wifes ride. Better mileage, more comfortable.

 

[Twinair]

I'm going to give it a try next fill if possible. Given the MPG's our rigs provide it may be first come, first served. I will post my experience. Stay tuned.

 

[ThomasMore66]

So far my venting is much reduced with ethanol free gas.

 

[Mountainpassing]

Well i ended up with woosh and gurgle a few weeks back as well. I had to call autozone to order the vc120 as it wouldnt let me internet order... Problem totally solved but the canister is a pig and i could only manage fitting it with the top strap,left the bottom strap bent away but still there. No new info here except the date 6-23-17

 

[Red Merle]

Well i ended up with woosh and gurgle a few weeks back as well. I had to call autozone to order the vc120 as it wouldnt let me internet order... Problem totally solved but the canister is a pig and i could only manage fitting it with the top strap,left the bottom strap bent away but still there. No new info here except the date 6-23-17

I had the same issue when installing the VC120. I ended up leaving the bottom bracket off after I painted the whole thing. It's not a perfect fit, but it's close enough. So far, I don't have any woosh since I put it in, but it hasn't been real warm yet. The old one had a completely clogged valve, so I am sure just being able to breath will take care of most of the issue. I also just removed the third hose that used to go into the bottom of the old can. I didn't see a need to keep it.

 

[LandCruiserPhil]

FWIW - If your charcoal in your canister in old or saturated you will get some fuel smell when it doing its job venting out the bottom of the canister. The line going to your fuel tank from the canister does not have a check valve and should be clear to the canister.

 

[DARKNESS]

My thoughts are ethanol boils off at a much lower temp than gasoline and builds tank pressure beyond the evap system's ability to vent. Once tank pressure reaches a certain point ethanol gasses remain suspended in the gasoline until you remove the cap and release the pressure. Once pressure is released, the dissolved ethanol gas is released much like opening a bottle of soda. After reading this thread I'm going to run ethanol free where I can and see if my tank pressure decreases. I haven't had the smell of fuel or a whining from built up pressure, just more fuel tank pressure than I'm comfortable with when I remove the cap.

Let's assume ethanol is the problem. New cars don't have this issue. Why? What is different about a modern evap system and how can we modify the 80's to mimic it?