spidey

I removed my charcoal canister and simply threw a plug on this hardline (circled in pic).



Questions:
What is this line? I'm assuming its just a vent from the fuel tank.
thanks for you help.

HarryB

In EUDM NB2s it is followed by a short length of rubber, ending up in the front subframe, so my guess is that's a vent.

SimBa

Reviving this thread. HarryB do you happen to have a photo of that rubber line? This line is capped on my car as well and I believe it is causing my fuel tank to not fill properly.
I figured running a bit of hose out to somewhere under the car might be a decent solution, but would like to see what an OEM solution without the charcoal cannister looked like (if that exists).

Z_WAAAAAZ

Yes, that line is the vent for your fuel tank. There's no OEM configuration without the charcoal canister AFAIK.

There should be a vacuum nipple on the right side of the front subframe that you can attach a line to for the fuel tank vent. I have an NA, not sure if NB location is different. Stock evap/vent line routing runs from the hardline in the photo, to a rubber line into the charcoal canister, then another rubber line from the canister to this nipple. When you delete the charcoal canister you just run a line straight from the hardline to the nipple on the subframe so your fuel tank can still vent.

If you uncap the evap line and still have fueling issues, there's a check valve or two on the evap line on top of the fuel tank that should be inspected as well. This valve (or valves depending on the year of your car) have a habit of getting stuck closed and clogging your vent line, leading to refueling and fuel tank pressure buildup issues. I was having fuel tank pressure buildup issues even after uncapping my evap hardline and removing the valves and replacing them with generic vacuum hose solved my issue.

SimBa

Thanks for the info. I have a CA NB1. I don't believe our cars have that vacuum nipple you mentioned. I have uncapped that vent line before and had an easier time filling up, which is why I suspect it. Granted, I also remember uncapping it and not having an easier time. I also remember seeing small bits of fuel spitting out of it when I did uncap it and fill up, which is why I'm hesitant to leave it totally uncapped.

I imagine running a loop of fuel line and then routing it down toward the ground would work, but I'm exploring options right now. I've also thought about doing a simple check valve and piping it into the intake (check valve to keep the turbo pressure from getting into the tank). I got the car with the vent line piped directly into the intake which caused issues with the car running rough for ~30 seconds after each fill up (unsurprisingly).

I've considered adding a small valve there as well, so I could manually vent it when filling, but I'd rather not have to pop my hood every time I get gas.