Guys, I failed my emissions pressure test for the fuel tank and I want to inspect this and make sure its not something easy like a rubber line before I pay to have it looked at or before I have to drop the tank. The rubber line at the canister visually looks ok and the rubber lines at the tank look ok too. There is an extra line im not familiar with that has what appears to be a check valve on it with the other end not connected to anything. Can anyone confirm whats in this pic? This line is coming from the fuel tank along side the fuel lines. I figure it could be leaking causing my problems and would be an easy fix. I just want to understand what it is and what it does. Name this part..

That is a check-valve that is supposed to only allow air into the tank in case a vacuum starts to develop. If you can smell gas fumes from it, then it's probably not working right.

Thanks for the reply.

Well I cant really tell if the fumes are from it or from something else since they kinda consume the entire area. Now that I atleast know what it is and what its suppose to do Ill check it out and see if its functioning properly or worst case grab a replacement.

Does anyone know, do these things commonly fail?

AZ what year is your car? IIRC there is a fuel tank recall for the 91 &92 thirdgens. That could be your problem. The recall involved the welds at the filler neck going to the tank. Do a search if your car is in the 90+ year range.

If they're that strong then check where the filler neck connects to the tank. Otherwise, the fumes could be coming from up top where the pickup tube assembly drops in. Perhaps the fuel pump has been changed? If so they may have left off the o-ring that makes the seal.

Thanks again guys. Yes it is coming from where the filler tube connects to the tank. Looks like a previous owner did an epoxy job on it and now its leaking again. Do you guys think I would have any luck with another repair job or do you think I should just replace the tank?

Oh and my car is an 88 so i guess im out of luck for the recall of the early 90s

I have a sportster that developed a crack in the tank where a bracket was spot-welded. There was no way to fix it without ruining the paint job, so I cleaned it all up as good as I could and filled the area with 2-part epoxy. Every one I asked said it would never hold. Hasn't leaked a drop in like five years and I'm a rare bird, I pop wheelies with my 1200. If that isn't stressing it, I don't know what would. 2-part epoxy is fuel proof when hard, but you have to have the surface free of any grease or oil when you apply it.