EVAP and tank pressure issues - where to start

We do have a non return valve which is just a "flapper" that allows gas to go into the tank but not back up to the filler neck.... The flapper can seize and not open and gas can't get into the tank.... One guy removed his so he could fill his tank.



 
Last edited:
One guy overfilled his gas tank and fuel went backwards down the vent tube and got liquid gas in his EVAP components... He ended up sucking liquid fuel into his catch can under the hood and it was gurgling like a bong.

I'm 98% you should have no liquid gas in the EVAP components.

When you fill your tank, air rushes out of the tank, through the "air filter" and on to the gas filler nozzle.
When the tank is full, the air stops flowing and that triggers the nozzle to shut off.

If the "air filter" is full of gas, it can't " breathe" so the filler nozzle shuts off... It can't push past the liquid blockage.
 
My issue came back. I guess I have to pull it all apart again and make sure I get every single line. It may be the part of the system under the hood? Wouldn't that show up as a code?

You may not get a code...

You may have a faulty "fuel shutoff valve"...
It may not be closing (or opening??) To stop the flow of air to trigger the gas nozzle at the pump to shut off so you mayb be continually over filling your tank and getting gas over flow to where it shouldn't be ??



That valve is inside the tank and the tank needs to be removed to test it.

I'm just kinda guessing here,..??
The EVAP / fuel system is a little hard to follow in the manual...
You may be able to find a workaround like removing that valve in the filler neck. ??
You may always have liquid gas in your system but it may still work without throwing codes??
 
Ok, im back now. I added a new canister at the back of the car(it was soaked in gas). Been able to fill up with an occasional stop in the filling. I recently have had it show up again. I can't fill my gas tank more than .2 gallons at a time. I also just got p0455, leakage or blockage code.

I will have to take apart every line I can get to. This sucks. Probably need a new canister as well. I plan on taking the charcoal canister under the hood as well, hopefully it is not clogged as well
 
I don't what's going on with your car.
The others who had problems just emptied the EVAP components and their problem was fixed as long as they didn't overfill their gas tank again.

Your code is probably due to a liquid gas blockage.

I'm pretty sure you should be able to blow through all the lines and components.

Perhaps is a faulty valve in the gas tank that's letting gas get in the EVAP lines ?

I don't know where the gas in your EVAP system would be coming from ?
 
Back