Evaporative Emissions System: Testing and Inspection
VISUAL INSPECTIONEnsure all vacuum hoses and electrical wires are routed clear of the exhaust manifold to prevent deterioration due to the high temperature. Vacuum hoses should always be a minimum of three inches from the exhaust manifold.
NOTE: Use only fuel resistant hoses when servicing the evaporative control system.
Tank Pressure Control Valve:
TANK PRESSURE CONTROL VALVE
1. Remove the rubber hoses.
2. Attach a vacuum operated hand pump and apply 7.5 - 8.5 kPa of vacuum to vacuum port (A) and blow into vacuum port (B) and the valve should be open.
3. Apply 7.5 - 8.5 kPa vacuum to vacuum port (B) with outlet port (C) capped. Air should not pass through.
Purge Control Valve Check:
CHARCOAL CANISTER AND PURGE VALVE
1. Inspect the charcoal canister for cracks or damage.
2. Check Purge control valve for proper operation.
a. When a 50 kPa pressure is applied to the port marked "V.C.," air should not leak from the diaphragm.
b. Apply and hold 14.96 in. Hg vacuum to the port marked "PURGE."
c. Apply vacuum gradually to the port marked "V.C.." If the purge control valve begins to open (vacuum decreases at the "PURGE" port) at vacuum between 1.6 and 3.2 in. Hg, the purge control valve is operating normally.