2013 Gas Cap Leak ?
 

Greetings everyone.

Hopefully someone can help me find a solution to a problem I'm experiencing with my ZN6.

I've read a significant number of threads relating to fuel leak issues but none of them mention what I'm experiencing.

So my car has no issues with pumping gas from the station, auto stops when full. I've stuck a borescope down the filler tube to check for collapse / obstruction, nothing. There are also no CEL or errors.

It does however always leak out the gas cap when I've filled it up and driven a short distance.

I've already changed the gas cap with a new OEM Toyota unit, no improvement. And I always tighten it properly everytime.

Could this be an issue with the EVAP system or perhaps even the one way valve ontop of the tank ?

Any assistance would be greatly appreciated.

Really basic and I am not trying to insult you but have you checked the filler tube top to make sure there are no foreign bodies that are preventing a good seal? A bad seal SHOULD trigger a CEL but it is possible it isn't and gas is sneaking through.


I do believe you are the first I have read with this issue.

No worries, sometimes the simplest things are overlooked.

I assume you mean the side of the pipe by the cap? Perfectly clean. I also had that thought initially, but alas, still does it.

The car itself is on 40k ish miles.

I was considering to stick my gopro near the cap and remove the flap to record exactly what happens after filling up. As it only leaks once and then seems fine until it's time to put in fuel again.

Does it happen if you don't fill it all the way? Just when totally full?

Good point. OP, how often has this happened? Maybe try a different pump at that station, maybe that pumps "clicker off" is not functioning properly.


humfrz

I've tried multiple stations and it happens irregardless.

It only happens when it's been filled up, the auto clicker/stopper working perfectly, stopping it on the gauge's full mark every time.

Since this car has a saddle tank that straddles the rear end maybe there's an air bubble in one side. Try putting the car on a side hill with the filler facing up and the cap off. Rock the car a bit and you may hear a gurgle as the bubble moves. I had this happen with my 2012 Challenger and ultimately ended up running the tank down to where the light was on for about 30 miles so it was really empty then filled up at a gas station with the car tilted that way and never had it happen again.