What are these port for on my fuel tank?

[LyleJ]

I recently had a new intake lift pump installed under warranty at tthe dealer. When I got home I pulled the bed to begain installing a flatbed. I noticed there where three hose barbs on top off the tank not attached to any items. I called the dealer but the mechanic who worked on it waqsn't in and the service writer on the phone didn't know what I was talking about. I have duct tape covering them right now while I pressure washed the frame. Any ideas should I plug them? One is located at the front of the tank and is a white 90 degree fitting. One is on the fuel pump assemble and one is on the top rear of the tank all with nothing attached.

 

[Hoefler]

The one on the fuel pump is a supply for a remote engine. The other 2 are vents. Folks on here have been installing short hoses on the vents to keep from sucking dirt and water that collects in the recess they sit in. The one on the fuel pump is supposed to have a cap on it if it is not used.

 

[Pawpaw]

Don't plug the other two. They allow air to enter the tank as the fuel level drops. If you plug them, you'll pull a vacuum in the tank. That won't be good for the lift pump.



The only problem with that is that they can also let dirt and water into your tank. The best solution is to put a short piece of 1/4" fuel line on each one, along with a cheap and small fuel filter. Tell the auto parts man you want a filter to fit a '69 VW Beetle.



Here's more info than you could ever want:



https://www.turbodieselregister.com...ssions/125393-check-your-fuel-tank-today.html



Bob

 

[JVantreese]

It is ok to seal off the vent tubes on the tank if you vent your OEM fuel cap. This allows the fuel to be removed from the tank without creating a vacuum in the tank. This will work fine UNLESS you are using a gravity feed aux tank. The gravity feed aux tank requires some back pressure to seal the check ball shut off valve that is installed in the fill hose of the OEM tank.