When driving my new to me 914 today I thought I ran out of gas. When I opened the Tank Filler Cap there was a whoosh of air. When I looked down the filler there was fuel. The gauge was reading 1/4 full. Is there a air vent to keep the tank from making a vacuum? My car is a 6 conversion and it's not using the return line.
It's been a while since I messed with a fuel tank.

Thanks
Van

Yes the tank needs to bar vented or a vacuum will build up preventing outflow of fuel.
I have a very small plastic tube venting to under the chassis, get no fuel smell.

@Van914
Inside of the filler neck is a metal tube about 4mm OD. It is pinched down on one end. If it gets plugged the tank can not suck in air to displace the gas.It normally connecte to the expansion tank.

Same thing happened to my carburated 914 years ago. Never had the problem until a long highway trip caused me to have the same symptoms you described. When I opened the gas cap to see if there was really fuel in there, like the gauge indicated, lots of whooshing sound along with metal popping sounds as the tank walls pushed back out.

My solution was to take the old vent line that ran to the back of the car (with the rest of the fuel lines), and remove the plug that was in it and install a small check valve device that is usually used in car emission lines. Now it will allow air to go in but none to come out.

When I get back from the Mid-Ohio this weekend with the Boxster I will check it.
thanks
Van

Thanks I will check it when I get back from Mid-Ohio this weekend,
Van

I've had a similar issue in my 2.0. I've tried to troubleshoot the vapor system but I still get vacuum inside the gas tank. I burned out a fuel pump last year which I attribute to the stress of pulling against vacuum pressure.