Gas spilling out of tank to EVAP charcoal canister line.

[qcon]

2013 Suburban 1500.

Been having issues with gas getting into the charcoal canister without knowingly overfilling. I’ve already replaced the canister, purge valve and vent valve 3 times and each time gas spills out of the charcoal canister. During the first replacement, a bunch of charcoal pellets were blown out of the EVAP lines and tank. No pellets since but still gas.

Today I decided to blow out the fuel filler neck and breather tube. Discovered gas in the breather tube as well as canister. I left the EVAP line disconnected from the canister and when I blew air down the fuel neck, gas spilled out of the disconnected EVAP line. Same thing if I blow air into the breather tube connection on the tank. So there doesn’t seem to be anything preventing gas flow into the canister. Is this a symptom of a bad roll over valve in the gas tank?

Thanks.

 

[mikez71]

Don't know..
Bumping thread...

 

[zbad55]

It sounds like the FLVV (Fluid Limit Vent Valve) may be bad, this is located inside the fuel tank and is snapped into the fuel Module.

 

[motomarktyf]

I had a similar situation with my 2007 Chevy Avalanche. It ended up being the vent tube broken in the gas tank and I had to replace the gas tank since it is plastic and not repairable.