Evaporative Emissions System: Testing and Inspection

VISUALLY INSPECT FOR:

1. A cracked or damaged vapor canister.
2. Fuel leaking from the bottom of the vapor canister vent hose. Check hoses and hose routing. Replace canister if necessary.



TANK PRESSURE CONTROL VALVE TEST

TEST DESCRIPTION:

1. Install a short piece of hose to the PCV tube of the purge valve assembly, and attempt to blow air through the hose. Little or no air should pass into the canister. A small amount of air will pass into the canister if the canister has a constant purge hole.

2. Using a hand held vacuum pump, apply 15" Hg (51 kPa) of vacuum to the control signal tube of the purge valve. The diaphragm should hold vacuum for at least 20 seconds. If it does not hold vacuum, the diaphragm is bad and the canister must be replaced.

3. If the diaphragm holds vacuum, attempt to blow air through the short hose connected to the PCV tube while vacuum is applied to the control vacuum signal tube. An increase in air flow should be observed. If not, the vapor canister must be replaced.