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

[markandson]

Originally Posted by MICAH1 That's correct, but only if your car is a 1973.

That's the only way he would have two tubes on the drivers side, he would have to be using a '73 tank.

[MICAH1]

Not stepping on toes here...... I have a 73 GT and also capped the tube for the stock filter return. I removed the plastic line running along the bottom of the car because my fuel filter only has the in and out connect to the weber.

[jvandyke]

Still dealing with gas fumes after car sits shut up for a while. Vent lines were done last year, today I replaced the gasket under the fuel level sender. OGTS sent a cork one, old one looked like it might have been cork in a future life. Are you supposed to use any sealant on this thing? I didn't. I did have two of the 5 holes stripped so replaced those two M5 bolts with similar sized self tapping screws, grabbed well so I'm hoping that's settled. Also replaced the rubber section on the filler neck. Old one looked fine. Could have just been the clamps, two different types were on there, I replaced one that was a Philips head clamp with a beefier one. If one of those two things doesn't do it, it must be the tank itself or the fuel outlet inside the little boot......now back to the oil leak.

[First opel 1981]

http://www.opelgt.com/forums/attachm...-fuel-vent.pdf

OK, color me stupid but which one of the connections in the diagram above goes to the fuel pump?

I have 3 fittings on the gas tank. One towards the front of the car (a vent line) and two in the back on the left side. One of those (the outer one) has a cloth covered robber hose connected. I assume this is the sump. The other is also a vent line ( I assume because it was rotted and the car still runs).

The diagram shows these two as one being a vent line and the other being a return from the fuel filter because this GT is a 73.

So, anyone know what is going on? Is there a fitting not listed on the diagram?

[MICAH1]

That diagram only shows vent lines.... The gas line (not shown) is the metal line to the right with the rubber bushing (cup) around it. It will run from the tank, to the fuel pump and up to the filter and carb.

[First opel 1981]

Originally Posted by MICAH1 That diagram only shows vent lines.... The gas line (not shown) is the metal line to the right with the rubber bushing (cup) around it. It will run from the tank, to the fuel pump and up to the filter and carb.

Fuel line is on the bottom of the tank? I ask because the only places gas can come from on the top side of the tank are all supposed to be vent lines according to the diagram. I have 2 side by side on the left rear of the tank and the single one on the right front.
I am sort of remembering that when I pulled a tank in about 1987 or so, I had to disconnect the fuel line on the bottom. It's been so long ago....

[markandson]

Originally Posted by First opel 1981 Fuel line is on the bottom of the tank? I ask because the only places gas can come from on the top side of the tank are all supposed to be vent lines according to the diagram. I have 2 side by side on the left rear of the tank and the single one on the right front. I am sort of remembering that when I pulled a tank in about 1987 or so, I had to disconnect the fuel line on the bottom. It's been so long ago....

Yes, the fuel line runs from the bottom of the tank and as stated above should have a large rubber dome shaped grommet around it. Right next to it will be the vent line that runs to the front of the car to the canister.

[First opel 1981]

I believe there is an error in the diagram for the vent lines.
The way it is lined out in the PDF http://clubs.hemmings.com/clubsites/...h/TankVent.pdf shows both the lower vent connections as being low enough on the tank to actually expel fuel directly to the charcoal canister if hooked up according to the diagram.

Here is where the problem occurs

Vent line orig.jpg

I believe if you look closely, you would realize that the revision in my diagram is the correct venting. This allows the highest point in the fuel system, where ONLY vapors should be present, to be the place where vapors are expelled to the charcoal canister.

vent line rev.jpg

Otherwise the upper vent would actually be capable of pushing liquid fuel to the charcoal canister.

Please advise me if I am wrong. Otherwise, I think it is very important for everyone to check their vent lines to see if they are properly routed.

[MICAH1]

Lets see, depending on the year of your GT, and I think you may have a 1973 one of those two line next to each other would be one to the canister, and the other to the gas filter return line. Some seepage from the tank may run into the canister line, but would only occur with a gas tank filled above the full level. I would think a functioning canister would cause the small amount of fuel to evaporate. But I thought your issue was referencing the location of the gas tank fuel line??????

[First opel 1981]

Originally Posted by MICAH1 Lets see, depending on the year of your GT, and I think you may have a 1973 one of those two line next to each other would be one to the canister, and the other to the gas filter return line. Some seepage from the tank may run into the canister line, but would only occur with a gas tank filled above the full level. I would think a functioning canister would cause the small amount of fuel to evaporate. But I thought your issue was referencing the location of the gas tank fuel line??????

Originally I was referencing the location of the sump line. I have gotten past that issue.


I was running the vent lines and noticed that when the car would stop, or start, with a full tank, the sloshing would cause gas to fill the vent lines. It occurred to me that with the small change to the diagram that I show, there would be no reason at all for liquid gas to enter the line that goes to the charcoal canister. I believe what I show should be the correct way to run the vent lines. I can see no possible harm but can also see the benefit.

Yes, I have a 73 and I know which one is the return line from the fuel filter. (I might add that its a great thing to have because it eliminates the vapor lock I used to experience on my 69).

I only posted the proposed change to the vent routing in this thread because I was trying to keep it in the same thread as venting in general. In all honesty, I debated the idea of giving it its own thread as a tech issue.

[MICAH1]

Understood. Maybe a rethink of the line route is a good thing for test, and discussion.

[Redskinsjbs]

Either way, these connections should not matter. The two 'T' connections are above the fuel tank on the 'ceiling' of that space back there, so no fuel should ever slosh out of the tank and down to the carb canister, it just is not pyhsically possible...I think.

[newman27]

Originally Posted by First opel 1981 ...I was running the vent lines and noticed that when the car would stop, or start, with a full tank, the sloshing would cause gas to fill the vent lines...

Not sure if you still are working on this but sometimes a picture is worth a thousand words. I have multiple photos in my gallery that show step by step setting the vent lines up (on a '72 GT). They used to be isolated in their own album but a recent change to the site seems to have combined all my older albums into one large group. Here is a link to one of the photos.

HTH

Matt

[Dale .D]

There seems to be 2 different ways people are using the T with the smaller hole in one end .No definate ruling as to which is right? The way OGTS has in it's teck tips is below the windshield with the smale hole going to the canister. The majority of this club is saying put the small hole at the filler hose.Which is right . Nothing in my manuals.Which way was it originally? The 2 logics say to have it at the filler to reduce fuel getting in the hose. the other ( OGTS) says at the other end so no fuel gets toward the charcoal canister.Who's right???Of coarse I could just be understanding things wrong.Wouldn't be the first time!Thanks for any clarifacation.

[markandson]

Originally Posted by Dale .D There seems to be 2 different ways people are using the T with the smaller hole in one end .No definate ruling as to which is right? The way OGTS has in it's teck tips is below the windshield with the smale hole going to the canister. The majority of this club is saying put the small hole at the filler hose.Which is right . Nothing in my manuals.Which way was it originally? The 2 logics say to have it at the filler to reduce fuel getting in the hose. the other ( OGTS) says at the other end so no fuel gets toward the charcoal canister.Who's right???Of coarse I could just be understanding things wrong.Wouldn't be the first time!Thanks for any clarifacation.

The small hole goes to the canister.

[First opel 1981]

I have found out that both tees have small holes. One has a small hole on the straight part and one has it on the upright of the tee.

Anyone else notice this?

[Dale .D]

Originally Posted by First opel 1981 I have found out that both tees have small holes. One has a small hole on the straight part and one has it on the upright of the tee. Anyone else notice this?

So is the answer both.??The back is still open & I have the small hole T to the canister.I can put one back at the filler tube too . Now would be the time!!!Anyone

[prostreetopelgt]

I have a 73 gt with same vent line problem's , also someone has removed the smog equipment , and also has some type of black plastic fuel line from tank to pump with a short section of rubber hose slipped over the plastic & hose clamps on both ends, no barbed ends here. Does not look correct , or at all safe . I am wondering if it is possible for this to run well without smog stuff on , and where to find a diagram to properly rout all of the fuel system hoses , vent lines , filters , charcoal canisters , everything look's original and shot . I would like to replace all, just want to do it right.

[First opel 1981]

Originally Posted by prostreetopelgt I have a 73 gt with same vent line problem's , also someone has removed the smog equipment , and also has some type of black plastic fuel line from tank to pump with a short section of rubber hose slipped over the plastic & hose clamps on both ends, no barbed ends here. Does not look correct , or at all safe . I am wondering if it is possible for this to run well without smog stuff on , and where to find a diagram to properly rout all of the fuel system hoses , vent lines , filters , charcoal canisters , everything look's original and shot . I would like to replace all, just want to do it right.

I just redid my fuel vent lines and described what I did in this thread
http://www.opelgt.com/forums/opel-te...e-rethink.html

Basically with the 73, you have to run a couple different hoses from the rest of the years.
The charcoal canister is NOT "needed" but preferred if you don't want to smell gas in your car or garage.

The hoses are pretty easy to figure out once you get the general idea of it. I will try to lay it out in a couple sentences.

1) There are 4 places to plug hoses into on the gas tank. One goes to the fuel pump, one is a front vent, one is a back vent and one is a return line from the fuel fileter near the carb.

2) The two vent lines go to a common TEE.

3) The main fuel line exits the bottom of the car and goes straight to the fuel pump.

4) The return line from the fuel filter connects to one of the fittings off of the tank in the rear on the drivers side.

In the thread where I describe what I did, there are diagrams to explain which fitting goes to what. The main idea for the charcoal canister is that the vents from the tank go to the canister to be absorbed by the charcoal. During normal driving the fumes collected in the canister are drawn into the engine to be harmlessly burned.

Hope that helps get you started.

[opellane]

Check post #108 Fuel Venting Diagram, Use the search feature " Fuel Venting Hoses" or check out this link:
http://www.opelgt.com/forums/attachm...venting023.jpg
And read some of the Tech Tips from Opel GT Source. Hope that will help you.

I changed my vent lines some 12 years ago with 3/8 black fuel line, but they seem to be cracking again,and get that smell from time to time. What is the "Very Best" Vent tubing out there is the Braided Stainless Steel? or a Heavy Black Plastic Trucker diesel fuel lines ?? I want the best tubing made, that will last forever.

[First opel 1981]

Originally Posted by opellane What is the "Very Best" Vent tubing out there is the Braided Stainless Steel? or a Heavy Black Plastic Trucker diesel fuel lines ?? I want the best tubing made, that will last forever.

I used steel.
No, not braided steel hose......STEEL!

[kwilford]

Originally Posted by prostreetopelgt I have a 73 gt with same vent line problem's , also someone has removed the smog equipment , and also has some type of black plastic fuel line from tank to pump with a short section of rubber hose slipped over the plastic & hose clamps on both ends, no barbed ends here. Does not look correct , or at all safe . I am wondering if it is possible for this to run well without smog stuff on , and where to find a diagram to properly rout all of the fuel system hoses , vent lines , filters , charcoal canisters , everything look's original and shot . I would like to replace all, just want to do it right.

The factory fuel line (and the tank vent line) are nylon right from the factory, which is what yours sounds to be. In my experience, this material is pretty durable, but specific conditions (or abuse) might certainly justify replacing it. The material of choice is steel fuel line, properly bent to fit in the OEM location along the tunnel.

The "smog" equipment on an Opel GT is pretty rudimentary, and consists mainly of the tank vent system incorporating a charcoal cannister. A brief search of this Forum (actually just read the first few "Sticky" threads in the Forum list) and your questions will be answered. The '73 GT had one feature specific to it, as it uses (at least from the factory) a special fuel filter with a fuel return, and a separate return line all the way back to the tank.

But in ANY event, the tank MUST be vented in some way, as it is otherwise sealed and if the vent lines are merely plugged, the fuel pump will pull the tank into a vacuum, and you'll be vapour locked.

HTH