Fuel leak from top of tank, no CEL
 

Boxster S, 2004
I fueled up the other day and the nozzle did not shut off automatically. I had fuel leaking from under the car, not overflowing from the top of the filler tube. I don't have any codes and the car runs fine. I've got it raised and put a little fuel in the filler tube and some fuel flows from the top of the tank someplace. I can't tell exactly where it's coming from, but I'm assuming its a vent. Time to drop the tank. Ugh!

You can get easy access to the fuel sending unit and hoses by removing the battery and battery tray. If it's leaking from the top, that is the most likely area for a problem. No need to drop the tank unless all of that looks good.

This Tech Article at Pelican has most of the procedure outlined with pics.

https://www.pelicanparts.com/techarticles/Boxster_Tech/22-FUEL-Fuel_Pump/22-FUEL-Fuel_Pump.htm

changed the sender last year
 

78F350 --I should have commented earlier that I changed the sender last year because it was leaking. It has not leaked since I changed it, and it is not currently leaking. I tried to get my wire camera up above the tank, but I haven't been able to see anything obvious yet. I put the camera down around the back of the top of the sender unit and I am unable to see any obvious problems.

Take the battery out and look.

I have inspected the top of the sending unit, and I put my camera down into the sending unit access port to inspect around it. No obvious leaks or parts breakage. That's one of the first things I did to check to see if there was a problem with the sending unit.

UPDATE: found the leak!
 

I was pulling the fuel lines off the top of the sending unit and the unit lifted up. :o I had inspected the fuel sending unit a couple of times since I first noticed fuel spilling, but I hadn't yanked on the fuel lines. I tugged on them, but apparently not hard enough. I never saw fuel in the top or around it, and I didn’t smell fuel when I lifted the cover from the battery tray. When I replaced it over a year ago I must not have seated it properly. All looked well and it was snug enough to keep things working properly, but not snug enough to keep fuel from spilling while fueling. I inspected the ring to make sure it wasn't cracked and put it back on SECURELY. I’ll finish putting it back together tomorrow and take it for a drive. Troubleshooting rule #1—Start at the point/location where it was touched last!