Fuel Evap System

[jcnunez85gt]

So i took my 85 gt to smog and it passed emissions but they hooked a computer to the gas tank which tested the fuel evaporation system. I dont know what that is but i need some help to figure out what that is. Any advice?

 

[HISSIN50]

Did it fail for the cap or for something with the tank?

 

[jrichker]

The code 85 test path will help you get some ideas on what the system looks like and how it works...

Code 85 - CANP solenoid - The Carbon Canister solenoid is inoperative or missing. Check vacuum lines for leaks and cracks. Check electrical wiring for loose connections, damaged wiring and insulation. Check solenoid valve operation by grounding the gray/yellow wire to the solenoid and blowing through it.
The computer provides the ground for the solenoid. The red wire to the solenoid is always energized any time the ignition switch is in the run position.

Charcoal canister plumbing - one 3/8" tube from the bottom of the upper manifold to the rubber hose. Rubber hose connects to one side of the canister solenoid valve. Other side of the solenoid valve connects to one side of the canister. The other side of the canister connects to a rubber hose that connects to a line that goes all the way back to the gas tank. There is an electrical connector coming from the passenger side injector harness near #1 injector that plugs into the canister solenoid valve. It's purpose is to vent the gas tank. The solenoid valve opens at cruse to provide some extra fuel.

Purge valve solenoid:

Carbon Canister:

 

[jcnunez85gt]

they connected what looked like a gas cap to my gas tank and that is what failed.





thanks for the diagram ill check that today.

 

[HISSIN50]

But what failed? What was it testing for? Was it a pressure test and the gauge didn't drop to zero quickly?

 

[tim281]

Filler neck gasket or routing to carcoal can... Maybe bad solenoid