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A few weeks ago, I smelled gas coming from under my 97 EVC. I have been unable to find the cause. The smell has been intermittent, three times over a one-month period. When it comes it is strong, but not overpowering. I can find no drips under the van or signs of leaks. After a few hours the smell dissipates. Each time it coincided with a 100 plus mile trip in hot weather (90 degrees.)

Yesterday I was able to make a diagnosis.? The tank seems to be under considerable pressure.? After yesterdays trip I once again smelled gas. I opened the gas cap and a rush of fumes expelled for a good couple of minutes until it finally stopped. This is the first time I noticed this, though previously I may not have opened the cap until the van had been at rest for several hours.

I am assuming that the tank has a pressure release vent that may be clogged. If this is the problem, how do I go about fixing it? But even if this is the problem, why would the tank be pressurized? I would have thought the opposite would occur. And why would the condition be intermittent?

I fear that I am driving a time bomb that could literally explode. I won’t be driving until I solve the problem.

Does anyone have insight into this problem? I’d appreciate any advice or insights. By the way, I am currently in Santa Fe in case anyone knows of a good shop in this area.

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Thanks,

Dan

97 EVC

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You need to have your evaporative fuel system looked at. Could be the valve, carbon canister setup

The pressure comes from the fuel pump is constantly circulating fuel, so you have warm fuel returning to tank

Stephen Jackson

Canoe-ventures

On Jun 20, 2015, at 9:59 AM, tidalwaifs@... [ev_update] <ev_update@...> wrote:

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A few weeks ago, I smelled gas coming from under my 97 EVC. I have been unable to find the cause. The smell has been intermittent, three times over a one-month period. When it comes it is strong, but not overpowering. I can find no drips under the van or signs of leaks. After a few hours the smell dissipates. Each time it coincided with a 100 plus mile trip in hot weather (90 degrees.)

Yesterday I was able to make a diagnosis.? The tank seems to be under considerable pressure.? After yesterdays trip I once again smelled gas. I opened the gas cap and a rush of fumes expelled for a good couple of minutes until it finally stopped. This is the first time I noticed this, though previously I may not have opened the cap until the van had been at rest for several hours.

I am assuming that the tank has a pressure release vent that may be clogged. If this is the problem, how do I go about fixing it? But even if this is the problem, why would the tank be pressurized? I would have thought the opposite would occur. And why would the condition be intermittent?

I fear that I am driving a time bomb that could literally explode. I won’t be driving until I solve the problem.

Does anyone have insight into this problem? I’d appreciate any advice or insights. By the way, I am currently in Santa Fe in case anyone knows of a good shop in this area.

?

Thanks,

Dan

97 EVC

?

Hi August and all?

Here is what I have learned?regarding Gas tank fumes and the Evap System Charcoal Canister.

Back before emission standards, fumes from the tank were released directly?into the environment via a?vent. The tank was an open system. When emission controls entered the scene, the open system was replaced by a closed system to prevent fumes from being released.?

The Evap canister is designed to accumulate fumes from the gas tank so that they can be burned, thus eliminating releases into the environment as well as preventing?pressure build up?in the tank. The canister is filled with charcoal particles to absorb tank fumes that can then be burned. There is a fan upstream of the canister that is activated when you turn on the engine. This forces the stored fumes into the fuel system to be burned rather ?than released. The problem arises if gas somehow gets into the canister which is only designed for fumes.?

This can happen if you over fill the tank by topping it off after the fill up shuts off automatically. The intake for the fumes, located at the top of the tank?takes in liquid gas. The gas then dissolves the charcoal which then clogs the system preventing the fumes from burning off and building pressure in the tank. If just a little gas gets in, the clog may be rather minimal just leading to minor pressure build up. If a lot of gas gets in, the charcoal can dissolve into a sort of muddy mess that completely clogs and shuts down the system. At that point, the only fix is to replace the canister which can cost up to $1,000 or so (I may be off on the price).?

If, however, the gas in the canister is minimal, the diminished capacity may be just a minor annoyance you can live with. Some have had success removing the canister and blowing out the liquids with an air hose. This is more likely to be successful if the amount of gas is minimal.?

The issue is exacerbated when it is hot, and at higher altitudes. I am currently in Santa Fe at 7,000 feet with 90 degree plus temperatures during the heat of the day. The fume and pressure build up is much greater during the day. When it cools down at night, 60 degrees or so, the pressure build up is far less.?

In my case, i think that a lot of gas got in. When I shut off the engine, I hear a gurgling noise coming from under the van that is presumably gas gurgling in the canister. Yesterday I had a shop remove the canister and blow air through it to open it up and force out as much gas as possible. Some folks have had success with this approach. I have yet to determine if this works for me. I'll report back in another post.

As far as safety goes, everything I've read and been told unanimously says this is not an issue. I've also been told that the tank can take considerable pressure. This is from web sites on various vehicles. While this may be true, my tank builds up so much pressure on very hot days that I'm not willing to take the risk. I fear that a hose or line might fail.?

Next week we are headed for Montana and then back to Seattle. My wife and I alternate drivers about every 200 miles, and we will be opening the gas cap each time we stop?to keep the pressure low.

We'll see how this goes. When we return to Seattle, we will decide whether or not to replace the canister. As long as we keep the tank pressure low, I'm not concerned about safety for the duration of the trip.?Back in cooler Seattle at sea level, this may be less of a problem.

This is probably way more detailed information than you were expecting. If anyone can add to this or if I have gotten any of the facts wrong, please straighten me out.?

In the mean time I intend to enjoy the rest of the summer...

Dan

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Dan Phalen