Fuel vent line hoses/fuel smell inside car!!!

[newman27]

Thanks all for the replies thus far. I was going to investigate the gas cap needing to be vented but I'll focus instead on the vent tubes themselves. My old gas cap seal must have been so bad that it compensated.

I am running "diagnostics" right now to determine the scenario that causes the vacuum to build. I'm checking the tubing back there each night after driving the car to see how things "flow" or change. Right now, for example, the driver side tube that runs from the filler neck to the top of the gas tank (which was completely full of fuel from the T-connector all the way to the gas tank) has decreased to just a small amount of fuel in the last few inches of the tube. The passenger side tube off the T-connector never had any fuel in it.

I'll just keep "burping" her every morning until I get more details...

Matt

[kwilford]

Matt, where does your vent tube end? In the engine compartment? Is it simply open-ended, or connected to the carb air intake, or?? If you don't know, you should ask Keith how it is hooked up.

Is there any chance that the tubing is kinked or blocked along the way? If you can find the open end at the front, you should be able to blow backwards down the tube (with the gas cap OFF!!) and the air should come out the tank filler tube. You should be able to blow it with even a breath, but avoid inhaling (!!) and perhaps use a clean piece of tubing to blow into. Or use a low pressure compressor. Whatever can establish flow backwards, with no more than a couple psi.

To understand what may be the problem, it might be helpful to understand how the gas tank vent system works (or used to work).

The OEM set-up had a single line run from the filler tube all the way to the front, via rubber hose until it exited the fuel tank area under the car, then nylon tubing to the engine compartment, where it connected to the charcoal cannister with another short length of rubber hose. There were other two connections on the cannister: one to the Solex carb float bowl vent, the other to a tube on the Solex body that connected to the inside of the throat. The cannister is simply a "temporary storage" device for gasoline fumes. Excess vapours from either the tank or carb float bowl would vent through the cannister if the car was running ("sucked" by the connection to the carb throat, which is at a very slight vacuum due to the pressure drop across the air filter). If either source of vapours vented while the engine was stopped, the charcoal would absorb the vapours, until they were released by the vacuum created the next time the engine ran. Simple as that, and used in virtually every car in the past thirty years.

Let us know what you know and find out.

HTH

[newman27]

Sorry, I keep forgetting to respond to the question of where the vent tube is going in the absence of a charcoal cannister and the fact that I no longer have the Solex carb.

I spoke with Keith over this past weekend and I believe the vent line runs straight down to the underside of the car at the rear (Keith - chime in here if I got that wrong).

My plan is to remove the deck in the spare tire area and check it out for myself but I just haven't had the time. It is difficult for me to find time on weeknights to do anything on the car so often times things wait until the weekend. My hope is that it turns out to be a kinked or obstructed vent tube as suggested by others here. I don't think I can tell for sure until I remove the deck in the spare tire area. Thanks again all for the comments and I will report back once I know more about the situation with the vent tube.

Matt

[newman27]

When I get a chance to get back in the spare tire area, I plan to take the recommendations in this thread and swap out the clear plastic vent tubing (even though it is new) with the rubber reinforced 5/16" fuel line and clamp everything down with some good clamps at each juncture. As far as the T-Connectors, I was intrigued by the earlier post that indicated the T near the fuel filler neck is supposed to be have a smaller diameter opening on the fuel filler neck side than on the other side:

Originally Posted by OpelJim I read Charles Goin's repair information and it is very good advise with the exception of the "5/16 th Tees" you can use from a local hardware store. The one "Tee" off the filler neck has a small pin hole opening on one side and a larger hole on the other. There is a design reason that small hole has to be mounted towards the neck This is to lessen the amount of gas that will flow down the line when filling the tank, and lessen the vapors that go into the compartment. If anyone wants the tech tip from Jim Petzold with instructions on how to do the repair and an easy to understand illustration too I can send them copies.

I found this universal vacuum tee that can be cut to different sizes on each of the three fittings. My question is whether or not fuel running through this plastic part would be of any concern? I'm just trying to be extra cautious here. It seems like it wouldn't be an issue and would allow for different sized openings at the filler neck side of the tee than at the other two fittings leading to the gas tank. Of course, assuming this part is acceptable, the next question would be how small to leave the opening on the filler neck side. Opinions?

Thanks!

Matt

[namba209]

Matt, I'm gonna guess, that because it's from Dorman's, an automotive parts store, it should be O.K. to work with the fuel system. I would leave the smallest opening attached to the "T" on the filler neck side, the other legs of it could be cut off to the nearest size of hose ID.

[jvandyke]

I thought I'd post a reference to a picture I labled in a similar thread.
post 22 and 23
http://www.opelgt.com/forums/fuel-ta...uel-smell.html

[newman27]

OK, I have completed the work on my vent lines to solve my gas tank vacuum issue. Since I had the spare tire tray out anyway, I decided to make some changes back there as an "upgrade":

• I tore out the existing clear tubing and replaced with rubber 5/16" fuel line. The clear tubing was only four months old but had already turned a yellow-green and become rigid in the places where fuel was sitting in them.
  
• I changed out the Tee at the filler neck to have a small opening on the filler neck side and a larger opening on the other two connectors of that Tee.
  
• I used FI clamps at every juncture between Tees and vent lines, etc.
  
• I altered the angle of the lines to match that shown in the picture posted by "jvandyke".

Materials required to go this route include:

(15') of 5/16" ID fuel line
(18") of 1/4" ID fuel line
(10) 5/16" FI clamps
(01) 1/4" FI clamp
(02) Universal vacuum Tees
(01) Universal vacuum straight

Total cost at Pep Boys: ~ $50.00. If you wanted to get the cost down a little, you really only need about 13' of fuel line. Also, you could eliminate the 18" of 1/4" line and the straight universal vacuum connector by drilling out the exit hole on the underbody to handle the 5/16" ID fuel line. I didn't want to drill, so I used a round metal file to slightly enlarge the existing hole and then stepped down to 1/4" ID fuel line for the last 18" of that run where it exits the body of the car. Doing it this way gives me a really tight fit and insures no water or gunk can get up into the body at that exit point.

NOTE: I don't have the charcoal canister anymore nor the Solex carb. So, my vent line just vents to the open air. It occured to me that a "funny" joke to play on someone with this arrangement would be to stick a golf tee in that tube. You would cause the vacuum issue to come back! Please don't do that to me if you see my car parked somewhere...

The photo that "jvandyke" posted above is really all you need to know what to do. However, I have posted some step by step photos in my member albums.

Thanks all for the tips and suggestions. I think this was worth doing to not only solve my gas tank vacuum issue but also add some additional safety measures. I don't know for certain that the clear tubing would have been a problem, but its physical properties (both color and rigidity) were changed in just four months of use.

Matt

[Nathan Acree]

You will definitely want to add a charcoal cannister. I have my car parked in my garage and if left there for a couple of days it reeks of gas!

-Nathan Acree
Albuquerque New Mexico

[newman27]

Originally Posted by Nathan Acree You will definitely want to add a charcoal cannister. I have my car parked in my garage and if left there for a couple of days it reeks of gas! -Nathan Acree Albuquerque New Mexico

Thanks - I am running a test on that right now. The car is parked in the garage at home all sealed up. When I get home from work today, I'm wondering what I will smell...

Matt

[jvandyke]

My line (that would/should/soon will again run to canister) has been open to the air since I got the car but I never smell gas OUTSIDE but I sure still do inside the cabin. I still suspect my fuel sender gasket is the culprit despite resealing it. Two of the 5 bolts wouldn't grab due to stripped threads (I think).
I think I had figured out that a cheap cannister that might work was from a Probe but I never did finish that off at the time I was searching they were $35 or so. It's on my winter to-do list yet.
PS the picture of my vent lines is just the way I did it, probably dictated by the lengths I cut, not necessarily any better or worse, is it much different than the stock set up?

[newman27]

Originally Posted by jvandyke My line (that would/should/soon will again run to canister) has been open to the air since I got the car but I never smell gas OUTSIDE but I sure still do inside the cabin. I still suspect my fuel sender gasket is the culprit despite resealing it. Two of the 5 bolts wouldn't grab due to stripped threads (I think). I think I had figured out that a cheap cannister that might work was from a Probe but I never did finish that off at the time I was searching they were $35 or so. It's on my winter to-do list yet. PS the picture of my vent lines is just the way I did it, probably dictated by the lengths I cut, not necessarily any better or worse, is it much different than the stock set up?

I haven't had any trouble with fumes inside the car except after the very first fill-up when I had just picked up the car. Since then, no problems. I forgot to mention that the hose that attaches the filler neck to the tank and the fuel sender gasket on my car are brand new and so I didn't change those out. If I were back there working on a car where these items had not been replaced recently, I would have changed those out as well. I'll know if I have any issue with fumes (inside or out) in a couple hours when I get home from work. If there is no issue, I plan to put the spare tire tray back in, reattach my amp, and consider it done...

NOTE: the June, 2004 Blitz apparently has an article with photos of the stock set-up. I don't have that issue however:

-------------------

June 2004
GT Gas Tank Venting (Hoses), 1 page (illustrated)
Photos illustrate correct vent hose routing from the GT fuel tank, including the 1973 GT fuel tank (which has an additional fitting). Changing these hoses (frequently rotted after 30 years of vapor exposure) will help rid the interior of gasoline fumes after a fill-up.

-------------------

Matt

[jvandyke]

Here's one from my 1970 owner's manual, but it doesn't show the filler neck line.

[kwilford]

Matt,

Did you run the vent hose to the engine compartment? If so, you can still hook it up (with or without a cannister, better with one) so that the fumes get "recycled" even without a Solex carb. Go to post #8 of
http://www.opelgt.com/forums/fuel-ta...cannister.html
for photo suggestions on how to hook the vent line up to a Weber.

HTH

[StefanLee]

I´m also looking for a solution to a smell-problem. I am going to add a canister since my car doesn't have one... My guess is a PO removed it when the fuel system was redone (poorly, I might add).

Anyway... My tank doesn't have the breather tubes on the top driver and passenger sides. Strange, innit? Did all GT tanks have those tank connections? I´ll have to add a breather hose to the top of the fill tube, but I won't be able to breathe from the corners. I hope the fill tube connection will do.

Stefan

[jvandyke]

So the tank doesn't have the inlets/ports in those corners either? PO didn't just remove/cap off the lines or something? Weird. Must not be a GT tank then?

[newman27]

Originally Posted by kwilford Matt, Did you run the vent hose to the engine compartment? If so, you can still hook it up (with or without a cannister, better with one) so that the fumes get "recycled" even without a Solex carb. Go to post #8 of http://www.opelgt.com/forums/fuel-ta...cannister.html for photo suggestions on how to hook the vent line up to a Weber. HTH

My vent hose is just exiting the body under the car to the open air. See this picture. However, I like the ideas in the thread you posted - I may pursue that - thanks!

Originally Posted by StefanLee I´m also looking for a solution to a smell-problem. I am going to add a canister since my car doesn't have one... My guess is a PO removed it when the fuel system was redone (poorly, I might add). Anyway... My tank doesn't have the breather tubes on the top driver and passenger sides. Strange, innit? Did all GT tanks have those tank connections? I´ll have to add a breather hose to the top of the fill tube, but I won't be able to breathe from the corners. I hope the fill tube connection will do. Stefan

I would try the vent line at the filler neck at least. Then, if you still have an issue with odors, it may be the filler neck hose and/or fuel sender gasket that is the source.

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Brief Update:
I have run two days of tests consisting of the car sitting overnight in the garage with doors down and all windows up followed by driving the car around town the next day. So far, no odors inside the garage or inside the car and, most importantly, NO VACUUM IN THE TANK! . So, this morning, I put the spare tire tray back in and wrapped it all up.

Matt

[StefanLee]

Yeah, I was a bit surprised to say the least. My tank looks exactly like a GT tank but is missing the breather connections completely. Then tank is smooth all around the upper edge. Maybe some GT´s came without those connections, or maybe the tank is from another Opel model of the age.

But I still think it is a proper GT tank, I can see from a listing on german Ebay for a GT tank that it also lacks the connections.

item 280197170705 on german ebay, ebay.de

Stefan

[Girly_with_style]

vent lines frustration i tore em out and didn't draw or take note they way they cam out now i have two tubes that i have no clue how they should go back in and the service manual doesn't really show either so im a bit lost any suggestions i know that the bottom T connects to the two knob things on the gas tank and that there is a tube that connects to the bottom and top T and that one side of the T goes to the top of the gas filling area and the other side of the T should that run out and under the car or what gee i can be rally stupid some times