Evaporative Emissions System: Testing and Inspection

Check for damaged components, cracked hoses, and loose connections and verify that the canister does not contain liquid. To check remove the canister hoses and inspect for the presence of liquid fuel. If liquid fuel is present repair or replace necessary components.


Charcoal Canister Purge Valve

1. Turn the ignition switch to the "RUN" (ON) position.

^There should be 12 volts present at terminal 82 of the 30°C Thermocontact. If not see "EVAPORATIVE SYSTEM ELECTRICAL DIAGRAM".

Emission Component Locations:

2. Bridge the wires at the 30°C Thermocontact.

^Purge valve should click
^Valve is open when unpowered
^Valve is closed when powered

Testing the 30°C Thermocontact

1. Remove the thermocontact and dip it in a container filled with cool water.

30C Thermocontact:

2. Measure the resistance across the terminals of the thermocontact.

^The resistance should be < 1 ohm (contact closed)

3. Heat the container progressively.
4. Check the temperature at which the resistance will go from less than 1 ohm (contact closed) to infinity (contact open).

^Readings should be as follows:
^Contact open above 86 +/- 5°F (30° +/- 3°C)
^Contact closed below 68 +/- 5°F (20° +/- 3°C)