Toyota 4-Runner 1985 Repair Manual page 132

EC-32
EMISSION CONTROL SYSTEMS (CARB.) - Exhaust Gas Recirculation (EGR) System
Above 44°C
Air Filter
Engine Stopped
Engine at 3,000 rpm
\
p
EC0120
Hot Water
EC0121
EC0335
3,000
III/
rpm
EC0336
6. CHECK EGR VALVE
(a) Apply vacuum directly to the EGR valve with the en-
gine idling.
(b) Check that the engine runs rough or dies.
(c) Reconnect the vacuum hoses to the proper locations.
IF NO PROBLEM IS FOUND WITH THIS INSPECTION, THE SyS-
TEM IS OKAY; OTHERWISE INSPECT EACH PART
A03050
INSPECTION OF BVSV
CHECK BVSV BY BLOWING AIR INTO PIPE
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Drain the coolant from the radiator into a suitable con-
tainer.
Remove the BVSV.
Cool the BVSV to below 30°C (86°F) with cool water.
Blow air into a pipe and check that the BVSV is closed.
Heat the BVSV to above 44°C (111°F) with hot
water.
Blow air into a pipe and check that the BVSV is open.
Apply liquid sealer to the threads of the BVSV a
reinstall.
(h) Fill the radiator with coolant.
If a problem is found, replace the BVSV.
INSPECTION OF EGR VACUUM MODULATOR
CHECK EGR VACUUM MODULATOR OPERATION
(a) Disconnect the vacuum hoses from port P,
Q
and R
of the EGR vacuum modulator.
(b) Plug port P and R with your finger.
(c) Blow air into port
Q.
Check that the air passes through
to the air filter side freely.
(d) Start the engine and maintain the speed at 3,000 rpm.
(e)
Repeat the above test. Check that there is a strong
resistance to air flow.
(f) Reconnect the vacuum hoses to the proper locations.
INSPECTION OF EGR VALVE
1. REMOVE EGR VALVE
Check the valve for sticking and heavy carbon deposi~
If a problem is found, replace it.
2. INSTALL EGR VALVE WITH A NEW GASKET