Hi all,
Just really starting to get to know my 914. Car has always smelled of gas and once my passenger complained of gas at her feet. The previous owner had removed the expansion tank and charcoal canister when he did the 3.0L swap which came with carbs.

I tried to do some debugging today to figure out where the gas was coming from. Only happens (or is noticed) with a full tank. I attached some small bags to the end of the hose that used to attached to the expansion tank, and to the large tube that comes off the "scupper" around the tank filler.

I noticed don't have the large hose that is in this picture that runs off the scupper. I could not find any diagrams for this line anywhere.



Where does the other end of that hose go?

Anyway... after a short drive with some quick side to side transitions (like warming tires) I stopped and noticed that BOTH bags had gas in them.

Is it normal for the evaporate line to have gas in it?
Where could the gas from the big tube be coming from? The gas cap SEEMS to have a good seal. Also, there doesn't appear to be any gas underneath the scupper. It doesn't appear to be leaking.

I also found this diagram but it doesn't show the large tube on the other side.



The two hoses that run the length of the car are still in the front trunk, but I'm not sure if they attach to anything in the engine compartment.

Thanks for you help.

hii,
i havent had my 914 that long, but i just had the tank removed to paint it, and the front end. The large pipe is just an overflow pipe that ends out underneath the car, and dumps spilled gas on the pavement.

Without that large hose, fuel spilled when filling the tank will simply run down the outside of the tank. That hose goes out the bottom of the car to safely dispose of any spilled fuel.

Your real problem is that when the PO removed the expansion tank, he most likely did not do anything with the much smaller vent hose.
This is where your car will leak fuel when the tank is full.


On my car, after i removed the expansion tank, i made sure the large hose goes through the bottom hole and sticks out 1/2" or so, then i took the small vent hose and stuck it INSIDE the larger hose.
That way, if i have a full tank and something comes out the vent hose, it'll simply drip down the large hose and exit on the bottom.

I still get the fuel smell every once in a while, but at least i don't have gasoline inside my car ...
Andy

Gas cap gaskets are usually hard and will allow fuel past. The small breather line on the neck can leak gas at a full tank.

Also, do you know the condition of the fuel lines under the tank? Those lines can leak, and the fittings themselves can leak.

And then there's rust, which can cause pinholes that leak fuel.

Gas smell in the cockpit can come from a number of places, some of them listed by previous posters:

1. The rubber gasket under the gas cap is probably hard. This isn't available anymore, but I was able to cut a replacement out of 1/8" rubber sheet, available from the FLAPS. Works great.

2. Any slight leak from the fittings at the bottom of the tank will generate a fuel smell. Even if the leak isn't large enough to wet the ground, the vapors will make their way into the passenger compartment. These fittings are sealed with small ring gaskets, no longer available. AA will sell replacements, but they're the wrong size. Again, I cut replacements out of gasket material, with good success.

3. Pay attention to the overflow tank lines, as mentioned.

4. Many times, the tank will rust where it sits on carpet pads placed by the factory between the tank and the inner fender of the car.

5. This one is from Chris Foley -- a sheetmetal screw was run through the passenger compartment firewall and it punctured the fuel tank on the other side. Moral -- don't mount your amplifier to the firewall using sheetmetal screws. (If your passenger is getting fuel on her feet, this is one way it could happen.)

Thanks all!

I was surprised by the amount of fuel that was coming out of those lines after a short trip.

Found this on ebay... suitable replacement gas cap?

http://cgi.ebay.ca/OEM-Porsche-356-911-912...%3A1|240%3A1318

It seems most likely the gas cap gasket but I'm still surprised at the amount of gas coming out the evaporator line. Especially since it has no path back to the tank.

Ok, the ebay one didn't fit. Any other sources for new gas caps for this tank (71) or should I just find some rubber gasket somewhere?

Thanks.

Here is a link to an exact IPB of the gas tank for 914's. The gas cap is number 6.
http://www.autoatlanta.com/model/porsche-9...arts/201-00.htm
Just click on the link for part 6's part number and it will give you these gas caps and prices
$40 for one from Germany, $28 for a used one, $20 for one made by Auto Atlanta.

I'd call Rich at High Performance House. he is great to work with and should have a good used one.

http://www.highperformancehouse.com/porsche/index.htm

I've had problems with AA myself.