Removing the Vapor/Liquid Separator Bottle (Avoiding a Molitove Cocktail Bomb!)

[Mikey]

Hey, wanted to pass this idea on to you guys and see if you think it would work...

I filled up both tanks the other day and noticed a really strong gas smell. Then I noticed gas seeping out of the panel where that little white plastic bottle is behind the driver's seat. I was very glad I have not installed carpet yet!

Soooo...I read up on this thing and kinda preferred to keep it. Then I thought....NO WAY am I allowing ANY gasoline inside with me in the Bronco! That's the dumbest thing I think I've seen Ford do!

I took the thing out and it was leaking along the seam and the PO had a fire as most of the lines were melted and not hooked up plus you can see scorch marks all in the area! Yikes!

I got some small fuel line and hooked the vents up like this....Aux tank connected to one of two Main tank vents. The second Main tank vent is connected to a fuel filter (flow pointed towards the tank). Then, the fuel filter is connected to the line going to my old charcoal canister. The canister is not connected to the air cleaner, just open to ambient air.

I realize I may over flow into the charcoal canister but I'm hoping the connection between the Aux and Main tanks will help that. If the charcoal canister does get hit with liquid, I figure it will dry out over time. An over flow on the Aux will only go to the Main so the concern is over flowing the Main.

What do you guys think? ?:?
Thanks,
Mikey

 

[skrit]

tear all of that emmission crap out of there. you don't need it.

 

[Jeepster]

if your in calif you do. Think twice before dumping it. If anything leave it there but just disconnect it just so it looks good.

 

[eb66to77]

I also took the evap tank out of the inside of my truck. I have the vent lines hooked up like yours also. I don't have my charcoal canister in there either. When my main tank vents it leaks gas everywhere and I am contemplating putting the charcoal canister back in there. I am going efi in the next couple months and can use that for the purge anyway. I don't see a problem with that. I am not a big fan of gas leaking out of the truck. If I were you I would add a type of "catch", like in a sink, to the line so that liquid has a harder time of traveling through the line than fumes.

 

[MarsChariot]

The liquid-vapor system is suppose to see mostly vapor. The liquid is a small amount that condenses inside the bottle, and then runs back to the tank via the lines at the bottom of the bottle. If that much liquid is getting into the bottle, then something is wrong with the lines and check valves. Sounds like that was out of wack from day one with yours. It is probably why the PO had problems.

I for one would not buy a Bronco that had the evaporative emissions system removed. Unlike a lot of seventies emission equipment this one does not affect performance. It might be o.k. to remove it for someone who parks the Bronco outside. But inside a closed garage. Bad news.

 

[Mikey]

The liquid-vapor system is suppose to see mostly vapor. The liquid is a small amount that condenses inside the bottle, and then runs back to the tank via the lines at the bottom of the bottle. If that much liquid is getting into the bottle, then something is wrong with the lines and check valves. Sounds like that was out of wack from day one with yours. It is probably why the PO had problems.

I for one would not buy a Bronco that had the evaporative emissions system removed. Unlike a lot of seventies emission equipment this one does not affect performance. It might be o.k. to remove it for someone who parks the Bronco outside. But inside a closed garage. Bad news.

Fundamentally, I agree with you. However, no gas should ever be piped in with you in the cab...especially vapors!....and in plastic! The classic Mustang community is all a buzz over the trunk bottom being the top of the gas tank and having no metal separator between the cab and the trunk. ...and that's far safer than having raw gas fumes plumbed in the cab with you in old brittle plastic.

What would be nice is for a good article showing proper vent line hook up using a new system outside the cab. My system should work except for liquid slugging the charcoal canister. What we need is some after-market hi po vapor/liquid separator safely mounted outside the cab somewhere. Is there such a thing that's fuel safe? I know I have a liquid (water) separator on my air compressor. Perhaps a similar device could be placed after my fuel filter set up.

Thoughts????
Mikey

 

[Mikey]

if your in calif you do. Think twice before dumping it. If anything leave it there but just disconnect it just so it looks good.

I also agree with you however my rig (for now) is exempt and no one can even find a proper diagram in the Bronco community....no way would an inspection station ever catch a missing bottle...they would look for the charcoal canister, though, and I'm leaving that there.

 

[DonsBolt]

The fuel evaporization control system prevents vapors from the fuel tank and carburetor from entering the atmosphere. Older, pre-emission vehicles used vented fuel tank caps. Carburetor bowls were also vented to the atmosphere. This caused a considerable amount of emissions. The major components of the fuel evapotization control systems are the sealed fuel tank cap, fuel air dome, liquid-vapor separator, roll-over valve, fuel tank vent line, charcoal canister, carburetor vent line, and the purge line.

SEALED FUEL TANK CAP is used to keep fuel vapors from entering the atmosphere through the tank filler neck. It may contain pressure and vacuum valves that open in extreme cases of pressure or vacuum.
When the fuel expands (from warming), tank pressure forces fuel vapors out a vent line or line at the top of the fuel tank, not out of the cap.
FUEL AIR DOME is a hump designed into the top of the fuel tank to allow for fuel expansion. The dome normally provides about 10 percent air space to allow for fuel heating and volume increase.
LIQUID-VAPOR SEPARATOR is frequently used to keep liquid fuel from entering the evaporation control system. It is simply a metal tank located above the main fuel tank. Liquid fuel condenses on the walls of the separator and then flows back into the fuel tank.
ROLL-OVER VALVE is sometimes used in the vent line from the fuel tank. It keeps liquid fuel from entering the vent line after an accident where the vehicle rolled upside down. The valve contains a metal ball or plunger valve that blocks the vent line when the valve is turned over.
FUELTANK VENTLINE carries fuel vapors up evaporization control to a charcoal canister in the engine compartment
CHARCOAL CANISTER stores fuel vapors when the engine is NOT running. The metal or plastic canister is filled with activated charcoal granules capable of absorbing fuel vapors.
CARBURETOR VENT LINE connects the carburetor fuel bowl with the charcoal canister. Bowl vapors flow through this line and into the canister.
PURGE LINE is used for removing or cleaning the stored vapors out of the charcoal canister. It connects the canister and the engine intake manifold.
Basic operation of a fuel. system is as follows:

When the engine is running, intake manifold vacuum acts on the purge line, causing fresh air to flow through the filter at the bottom of the canister. The incoming fresh air picks up the stored fuel vapors and carries them through the purge line. The vapors enter the intake manifold and are pulled into the combustion chambers for burning.
When the engine is shut off, engine heat produces excess vapors. These vapors flow through the carburetor vent line and into the charcoal canister for storage. The vapors that form in the tank flow through the liquid vapor separator into the tank vent line to the charcoal canister. The charcoal canister absorbs these fuel vapors and holds them until the engine is started

 

[Mikey]

Excellent! With the exception of the carb and everything up from the purge valve, all is there (Not much but still....). This diagram doesn't include that separator bottle, though. Does the Bronco have a purge valve?

 

[Jeepster]

I wonder if the location of the plastic jug inside the cab has anything to do with having to have the jug above the gas tanks to prevent siphoning raw fuel into the jug instead of vapors. Well atleast that would be my assumption.

 

[JoseyWales]

Reviving Gas Vent Discussion

Hi All. I just got a used aux tank to replace the one that was broken when I bought my 75 Bronco. The PO had re-plumbed the fuel system, and I'm trying to figure out how to vent the whole thing properly. I have these questions...

1. With the charcoal canister connected as intended, is engine vacuum applied to the tank vent lines? Can that fuel evaporation system work without a liquid-vapor separator?

2. Did all Broncos with the sealed fuel system come with a plastic vapor collection bottle behind the driver's seat? Mine doesn't have that (may have been removed before I bought it).

3. Has anybody tried to use engine vacuum to the rear tank vent to pull fuel from the front tank to the rear? That would eliminate the need for the tank selector valve. The front tank would have to be vented to atmospheric pressure though. I wonder if that would cause the rear to overfill.

4. How are tank vent systems set up on modern vehicles?

 

[Mherriford]

could you just run a vented fuel cap?

 

[Dawg_enD]

1. With the charcoal canister connected as intended, is engine vacuum applied to the tank vent lines? Can that fuel evaporation system work without a liquid-vapor separator?

2. Did all Broncos with the sealed fuel system come with a plastic vapor collection bottle behind the driver's seat? Mine doesn't have that (may have been removed before I bought it).

3. Has anybody tried to use engine vacuum to the rear tank vent to pull fuel from the front tank to the rear? That would eliminate the need for the tank selector valve. The front tank would have to be vented to atmospheric pressure though. I wonder if that would cause the rear to overfill.

4. How are tank vent systems set up on modern vehicles?

1. If I remember correctly, the cannister is connected to the intake, near the air filter, by a pair of corrugated hoses approx 3/4 in diameter. I don't believe they get true vaccuum, probably just a bit of venturi effect sucking the vapors up into the intake so the carb can burn them. The two hard lines entering the cannister were from the fuel tanks. They are the lines the vapors from the tanks travel through to get to the cannister. There isn't a vaccuum connection involved that I know of at all.


3. This sounds a little hoaky to me. It seems like it would be a lot easier to just run a second fuel pump back there on a switch. When you want to push fuel from the front tank you could just turn it on.

Thinking about it more... don't you need that engine vaccuum to make the motor run right? If it was pulling on the fuel tank you'd end up sucking losing your vaccum by sucking from the charcoal cannister, right? Plus, if the tank was really full don't you run the chance of sucking liquid fuel up into your vaccuum system? I don't really know a lot about the vaccuum stuff, so maybe I'm way off base, but that's what pops into my head.

 

[JoseyWales]

Running vented caps is an option, but I don't like the way they stain the side of the vehicle around the caps. I always thought the charcoal canister was garbage, but it might be the best way to filter gas fumes in the garage.

I think one of the corrugated hoses on the charcoal canister connectes to the air breather... at least that's what it looks like on my factory one.

There would be a little vacuum loss unless the charcoal canister has a way of regulating it somehow. It would probably be minimal though by the time the vacuum runs from the engine to the rear tank and then back to the front tank, and the loss would only occur when the front tank was emptied. It probably is not a great idea, but I just wanted to know if anybody had tried it. I think before I added another fuel pump, I would just reconnect the tank selector valve that the PO bypassed.

 

[Dawg_enD]

You are right. One of the corrugated hoses was to a breather. I forgot about that part.

 

[Mikey]

Yeah, one to the air cleaner and the other is open to ambient so you would suck continuously through the charcoal can. The part attached to the air cleaner is prior to the actual air filter if I remember correctly. Hence, no vacuum leak, just pulling some of your air through the charcoal can...which would be filtered except for any fumes. Hey, a mini cold air duct!

The charcoal can is good, not bad like everyone thinks. Absorbs the fumes and allows them to be burned through the exhaust. Modern cars do this but the computer controls when by opening valves. The bottle is a good idea but in a bad spot. Modern cars have this bottle built into the regular gas tank. You can run a vented cap if you do some sort of mods as the two are not interchangable. Other threads show how. However, your Bronco will stink of gas and be dangerous in your garage.

 

[behemoth]

I had the plastic bottle and it also was cracked and leaking more than say condensation. I noticed it more after installing the NWMP tank. It was determined that the breather or vent tubes were just welded onto the side of the tank near the top. So if I filled the tank with fuel I could put them under the level of fuel. The stock tanks vents were on tubes that went to the near center bump on the tank and had the ends pinched. This made it much more difficult to get fuel into the tubes in any quantity.

I removed the bottle and vented the tanks to the mustang charcoal canister and used the canister purge with vented caps. I have little to no fumes in the garage.

I have fuel injection and I plumbed my dual tanks as a transfer system from the aux to the main. The issue I ran into is that the main sits in the frame rails and the aux sits higher much higher so you can siphon from one to the other. I do not know if the circulating fuel added to this but I did experience this more than I remember noticing. I would drive on the main tank for ever and the gauge would always say full, flip to the full aux and it was near empty.

My plan is to vent the two tanks together and use a clear see through filter before the charcol canister and run the purge. What I can not remember is if I will need vented or non vented caps at that point.

 

[Mikey]

I ran one of those clar glass things and almost burned up my Cougar when the o-rings let loose!

 

[flaconinja]

So i just bought my bronco a week ago and it has two open nipples from the main and the aux is ripped out. looks like whoever did this just let them be the vent.

Does anybody know where to buy the separator and charcoal canister at?

Thanks