I cut open a gas tank and EVAP canister to see what’s inside and how it works. I made a short video on the process, you can check it out here:


Here are a few photos of the teardown:
The EVAP canister is located behind the gas tank:

The gas tank is held on by two straps. Boy was there a lot of rust on this Corolla! Down comes the tank:



One bolt for the filler neck:


Gas tank, EVAP canister removed:


Here’s what some of those vacuum lines do:

Vacuum lines on the gas tank:

Here’s an overview of the EVAP system. Its basically there to vent gasoline vapors and catch it in the charcoal canister. Its held there until its released into the car’s air intake to get burned by the engine.

EVAP float to ensure liquid gas doesn’t go into the charcoal canister:

Here’s the gas tank chopped open:


Vapour pressure sensor. ECU uses this for self-diagnostics. That’s why it’s so difficult to pass emissions tests!

Fill check valve. This controls the ventilation of the gas tank while refueling.


Its pretty cool inside, there’s a diaphragm that works with air pressure.

It allows vapor to move in one direction only

Chopping open the charcoal canister:

Tiny beads of activated charcoal:

Which gives me an idea…Barbeque anyone?

 

Your tutorials and videos are very cool. You must be having a blast taking apart this Corolla.

 

Thanks! I sure am learning a lot by taking apart this car. Its fun and a great learning experience.

 

I never knew Toyota makes cars out of compressed rust.

 

Great pictures. I'm trying to find small evap. leak codes P0442 & P0440 . I've used smoke test and can't find any leaks. great help with the labeling of hoses on the charcoal canister. Where is that vapor pressure sensor located(in tank)? At the end of the fuel line going in the tank as your picture shows? Never mind it,s at the other end.

 

Great video explanation! Thank you! This has been enlightening as I have been trying to understand exactly what the EVAP VSV's function is in this system.

 

Found leak causing codes p0442 and p0440 . The hose going to the back of air cleaner was cracked even though it looked good you could see it when I bent it. Smoke test doesn't send smoke there if using green port(schrader valve).

 

Thats was a really informative post. the gas pump keeps clicking off when I pump gas. Im goint to put some air in the tubes to see if there is a blockage.