Fuel Tank Overlows When Filling Up

[chris belyea]

Hi all,

When I purchased my 1970 E, the fuel tank ventilation system had been completely removed. I’ve now restored the system to what I believe is the original configuration. I’ve now filled the tank up twice and both times, the gas starts to overflow into the overflow tank before the pump will cut off. Each time upon fill-up, I ‘ve opened the hood to watch the fuel tank ventilation hoses and each time the gas spills over into the 3/4" hose next to the sending unit. Is this normal? I would have thought that pump would cut off once filler neck filled up but I don’t see how this can happen since the filler neck is much higher than the overflow.

Thanks

Chris

[Lyle O]

Our 911s are notorious for being fill-up finicky; I have to fill with the pump handle pointing directly to the front of the car/the hose is nearly on the windshield. If I don't do this, the pump cuts off or, occasionally, overflows. There are several threads here about this. It doesn't mean you don't have something else going on with your fuel-fill system, but just saying it has its peculiarities...

[E Sully]

The evaporative emissions systems purpose is meant to catch the overflow when filling the car. A small amount of fuel will flow into the tank when filling up.
As shown in the diagram, the purpose of the tank (2) in the left fender well is to capture the overflow, and then direct it back into the fuel tank as the fuel level goes down.
It also directs fumes into the intake to be burned instead of being released into the atmosphere.

[GH85Carrera]

Originally Posted by Lyle O

Our 911s are notorious for being fill-up finicky; I have to fill with the pump handle pointing directly to the front of the car/the hose is nearly on the windshield. If I don't do this, the pump cuts off or, occasionally, overflows. There are several threads here about this. It doesn't mean you don't have something else going on with your fuel-fill system, but just saying it has its peculiarities...

Really?

On my 85 I have no issue as long as I don't shove the nozzle all the way deep inside. I just raise it up enough to stay in place, and turn it on and forget it. It has been that way in the many different states I have been to. Easy Peazy.

[Lyle O]

Yes, really. Well known issue. Glad you have a good one...

SLOW fuel filling

[bkreigsr]

Originally Posted by GH85Carrera

Really?
On my 85 I have no issue as long as I don't shove the nozzle all the way deep inside. I just raise it up enough to stay in place, and turn it on and forget it. It has been that way in the many different states I have been to. Easy Peazy.

NJ has a vapor recovery system in the nozzle. - Very finicky unless you fuel with the nozzle straight up - achieved by rotation the handle release to point towards the passenger side.
(no extra effort is needed on side-fill tanks)
YMMV

Bill K