Canister Purge Control Valve: Testing and Inspection

Fig. 23 Purge control diaphragm valve check. Typical:

WITH ENGINE COLD

1. Ensure that coolant temperature is below set temperature of thermovalve.
2. Disconnect upper hose at purge control diaphragm valve and connect vacuum gauge to hose, Fig. 23.
3. Start engine and run at idle.
4. If there is no vacuum, disconnect vacuum gauge and reconnect hose.
5. On 1982-83 models, if there is vacuum, test thermovalve as follows:
a. On all but 1983 Prelude, drain coolant until its level is lower than distributor holder.
b. On all but 1983 Prelude, remove distributor holder from cylinder head, then remove thermovalve.
c. On 1983 Prelude, remove thermovalve from right side of intake manifold.
d. Suspend thermovalve in container of cold water with hand vacuum pump attached to lower port and place thermometer in container without allowing it to touch bottom of container.

CAUTION: Do not allow water to enter vacuum ports of thermovalve.

e. Draw a vacuum on thermovalve, then slowly heat water while observing gauge and thermometer.
f. Ensure that thermovalve does not hold vacuum below 97-111 deg. F, but does hold vacuum above 115-129 deg. F.
6. On 1984-86 models, if there is vacuum, replace thermovalve.

WITH ENGINE HOT

1. Disconnect upper hose at purge control diaphragm valve and connect vacuum gauge to hose.
2. Start engine and run until it reaches operating temperature.
3. Ensure that there is vacuum at idle. If so, disconnect vacuum gauge and reconnect hose.
4. If vacuum is not available, pinch hose between thermovalve and air filter and, if vacuum is now available, replace thermovalve.
5. If vacuum is not available when pinching hose in step 4, check for leaks or blockage in hoses 7 and 19 on all 1982 and 1983 Civic and Accord, hoses 17 and 19 on 1983-86 Prelude and 1984-86 Civic, hose 18 on 1984 Accord and hose 19 on 1985-86 Accord.