Toyota 4-Runner 1985 Repair Manual page 164

EC-64
Lower Port
Vacuum Switch
EMISSION CONTROL SYSTEMS - Auxiliary Systems
EC0340
EC0398
EC0399
EC0400
EC0403 EC0401
PREPARATION:
(For vehicles with HAC system)
Disconnect the vacuum hose from the lower port of the H.
valve, and plug the hose end.
A03082
INSPECTION OF DECELERATION FUEL CUT
SYSTEM
CHECK SYSTEM OPERATION
(a) Connect a tachometer to the engine.
(b) Start the engine.
(c) Check that the engine runs norma"y.
(d) Pinch off the vacuum hose to the vacuum switch.
(e) Gradua"y increase engine speed to 3,000 rpm. Check
that the engine misfires slightly between 1 ,800 and
3,000 rpm.
CAUTION: Perform this inspection quickly to avoid
OV(
heating the catalytic converter.
(f)
Release the pinched hose. Again gradually increase
the engine speed to 3,000 rpm and check that the en-
gine operation returns to normal.
(g) With the engine idling, unplug the wiring connector
to the solenoid valve. Check that the engine idles
rough or dies.
CAUTION: Perform this inspection quickly to avoid
otherheating the catalyst.
(h) Stop the engine, and reconnect the wiring. Remo'
the tachometer.
IF NO PROBLEM IS FOUND WITH THIS INSPECTION, THE
SYSTEM IS OKAY, OTHERWISE INSPECT EACH PART