TESTING

There are several things which should be checked if a malfunction of the evaporative emission control system is suspected. These include deterioration of the vacuum lines, deteriorated, disconnected or pinched hoses, improperly routed hoses and/or a defective filler cap.

In the most severe cases of evaporative emissions system failure, the fuel tank may collapse. This condition is caused by a clogged or pinched vent line, a defective vapor separator, or a plugged or incorrect filler cap. The incorrect or faulty components do not allow the fuel tank to breathe and thus create a vacuum in the tank, causing it to collapse.

System Operation

Visually inspect the entire system for kinked, cracked, swollen, plugged or fatigued hoses. Replace the vapor canister if cracked, damaged or if fuel is leaking from the bottom.

Purge Lines and Canister

1. Remove the fuel filler cap.
2. Disconnect the evaporation line at the evaporation pipe.
3. Check for an unobstructed evaporation line on the fuel tank side by blowing air into the hose. A little resistance should be felt due to the two-way valve.

   NOTE: Take care not to suck on the hose as this causes fuel evaporation vapors to enter your mouth. This may cause serious injury.

4. Check for an unobstructed evaporation line on the canister side by blowing air into the hose. A little resistance should be felt due to the two-way valve.
5. If an obstruction is found, remove the two-way valve and retest. If the obstruction is still present, clean or replace the line. If not, test the two-way valve and replace as necessary.
6. Check all lines for cracks or deterioration. Replace as necessary.
7. Check the exterior of the canister for damage and replace as necessary.

Two-Way Valve

1. Remove the two-way valve.
2. Check for air passage by blowing air into the lower nipple. A little resistance should be felt due to the functioning of the valve.
3. Repeat the test blowing into the upper nipple.
4. Check the valve case for cracks for deterioration.
5. Replace the valve if it fails any of the above tests.

Float Chamber Ventilation Valve

This valve is used on carbureted engines only.

1. Check the resistance between the positive and negative terminals. Resistance should be 16–20 ohms for the Justy and 32.7–39.9 for all other vehicles. If not, replace the solenoid valve.
2. Check the resistance between the Positive and negative terminals and the solenoid valve body. Resistance should be 1M ohm or more. If not, replace the solenoid valve.
3. Check the vacuum passage for opening and closing operation while applying electric current to both positive and negative terminals. If the vacuum passage fails to open when current is not applied or fails to close when current is applied, replace the solenoid valve.

Fuel Filler Cap

1. To test the filler cap, if it is the safety valve type, clean it and place it against your palm.
2. Blow into the relief valve housing.
3. If the cap passes pressure with light blowing or if it fails to release with hard blowing, it is defective and must be replaced.