P0455,evap system leak (large)

[fixkick]

if the caps seals,and you reset 455s
and it comes back you have an EVAP breach.
it is a large leak
there are only 2 ways, besides, looking for rusted top of tank or hose cracks
that is pressure testing or vacuum testing it, called a leak down test.
one way is use a LPHV spray paint gun regulator, set to 1 or 2 psi, lowest possible (got shop air?)
then pressure the system.
then listen for leaks using a rubber hose to ear.
and or use soapy water to find bobbles, same way the gas man finds gas leaks on furnace leaks.

http://www.fixkick.com/sensors/EVAP/Evap-testing.html

that smelt fumes is wrong.