0455 - evap leak

[nicholasd]

Hey Guys,
I've been trying to hunt down an evap leak for a few weeks, but just when I think I've got it taken care of the code comes back! Is my last option a smoke test? Should I go back to the dealership or will most garages be able to do this pretty quickly?

[KJK]

I have never heard or such a thing. How do you.perform a smoke test? Is it something you can purchase at an auto parts store and do it yourself?

[nicholasd]

I actually managed to get my hands on a smoke machine through somebody I know. Just a machine that blows smoke out of it and has an attachment for the Schrader valve for the evap system. Looked around for leaks for 10 minutes, but nobody could find anything. Oh well.  Didn't think to try smoking it through the gas tank filler, which is what I might try next.

[wheelincj5]

Just a sugestion..try replacing the gas cap..if the vent allows gas fumes to escape into the air its defective..should only allow air to enter the tank as fuel is being used.

[nicholasd]

Thanks for the suggestion, but it was definitely the first thing I tried. No luck unfortunately.

[RussJr]

check your vent tube from the gas tank.  i know mine worked its way lose on my trailblazer. kept throwing codes like crazy.  dealership charged me lots of money never found the problem.  I did.