Hey fellow members, i'm having a difficult time diagnosing my issue and hope someone here has some insight. I'm getting the engine code P0456 (small leak detected in evap system) When the tank is full the cabin and outside rear of the car reaks of gas. Once the tank is 3/4 or less the smell is gone.

Things i've done:
1. New filler neck - old one was rusted to hell. Thought this was my issue since the vent lines crumbled in my hand.

2. Passed the smoke test at the Mitsu dealer. No visible signs of leaks and all solenoids work as should.

3. Inspected top of tank under service panels. Moved all lines by hand to see if leak exists.

Dealer suggest ventilation solenoid could be stuck open but i'm thinking if it was stuck open smoke would have been pouring out during the test.

I don't where to turn at this point especially since I passed the smoke test. Really hope someone can help. Thanks in advance...

 

Forgot to mention car is all stock...

 

So, I spent about an hour last night going over every line and basically just following my nose. There does seem to be a consistent smell by the fuel pump assembly (drivers side) which would explain why the smell is in the cabin. Though I can't see any visble signs of where a leak could be, vent hose looks fine as well as both fuel line connections.

Has anybody heard of the pump assembly gasket randomly failing?

 

Since the car is stock. Take it to the dealership and have them fix it. Its likely they offer some sort of warrenty on the repair..1 year and or some amount of miles. If they get it wrong, bring it back under that repair warrenty and have them fix it again for free.

All parts work untill they fail. Its the reason a dealership has a service department. New cars break down as well.

 

you prob have a leak on your fuel tank(under car)

 

Its not a new car, its an 03 with no warranty. Per my first post, I did take it to the dealership for the smoke test, they never found a leak so they have nothing to fix...


I'm thinking its the fuel tank as well but on top of the tank where a smoke test is easily missed. I ordered a new fuel pump assembly gasket and the retainer since thats the area with the strongest scent of fuel.

Process of elimination at this point...

 

My fuel tank leaks a small bit if I put it to a full tank which also comes with that raw fuel smell. I believe I got a fuel related code which I disabled in the periphery settings.

Fill your car up and check for drips and you probably will source your leak right where the tank meets the body of the car

 

Did you find your leak and fix it, if so where exactly was it leaking?

I'm not getting any puddles or drips in my garage when I fill up, which makes it even more difficult to find. Mine is probably so small that it evaporates before it has time to leave a trace...

 

Found, not fixed.

 

Just a small update. I haven't had time to drop the tank nor could I put in the new fuel pump assembly gasket due to a rounded nut from the last owner. I swear some people should NEVER touch a car.
Anyway, my check engine light has not come on since I installed a new filler pipe tho I still have a strong fuel smell on full tank. The fuel smell and no light is throwing me off, I know this means something but not sure what. Clearly there is a hole somewhere but its strange it doesn't trigger a check engine light...