Hey yal, so my girls 2004 civic LX has small EVAP leak. I smoked tested the system and couldn't find any leaks. She mentioned every time she fills up, there's a lot of pressure when undoing the gas cap. All sensors/solenoids work as I can turn them on and off with scan tool. Should we drop the tank?

 

We replaced the charcoal canister already and no fix. I smoked the line from the purge solenoid to the rear of the car. See no leaks. Sprayed soapy water around charcoal canister, couldn't see anything.

 

What is the code? P1456 (Fuel Tank System) or P1457 (EVAP Canister System)?

Common problem with these cars is P1457 for a faulty By-pass (Canister) Shut Valve (CVS)/Canister.

 

Did you try just blowing into the line going into rear purge valve? Mine didn't leak when smoked, but when I blew into it, you could audibly hear pressure escaping from where the plastic and metal components of the valve were no longer sealing. Once I dropped he rank a bit, it was corroded to hell. (full disclosure - this was on my EJ8, not an EM2/EP3)

 

I can't remember the number but it was small EVAP leak by canister.

 

When you say rear purge valve, which one? There's like 2 or 3 on the charcoal canister. We replaced the canister and the other valve that goes into the front since hers was rusted and cruddy. I took the line that leads to the back, and that checks out but didn't blow air. Just tried smoke.

What could cause extreme pressure in the tank? It's almost like the tank swells up from the pressure. Is there a fuel pressure relief valve or something on the tank?

 

Bump

 

Bump

 

Did you ever solve the problem?