Toyota 4-Runner 1985 Repair Manual page 112

EC-12
EMISSION CONTROL SYSTEMS (EFI) -
Exhaust Gas Recirculation (EGR) System
COLD
3,500 rpm
Tachometer
HOT
3,500 rpm
Tachometer
ECl901
Vacuum Gauge
EC0985
Vacuum Gauge
EC0139 EC0128
Low Vacuum
Vacuum Gauge
EC0139 EC0129
Vacuum Gauge
/
, EC0986
INSPECTION OF EGR SYSTEM
1. CHECK AND CLEAN FILTER IN EGR VACUUM
MODULATOR
(a) Check the filter for contamination or damage.
(b) Using compressed air, clean the filter.
2.
PREPARATION
Disconnect the vacuum hose from the EGR valve and, us-
ing a three way union, connect a vacuum gauge to it.
3. CHECK SEATING OF EGR VALVE
Start the engine and check that the engine starts and runs
at idle.
4. CHECK BVSV WITH COLD ENGINE
(a)
The coolant temperature should be below 30 D C
(86°F).
(b) Check that the vacuum gauge indicates zero at
3,5
r
rpm.
5. CHECK BVSV AND EGR VACUUM MODULATOR WITH
HOT ENGINE
(a) Warm up the engine.
(b) Check that the vacuum gauge indicates low vacuum
at 3,500 rpm.
(c) Disconnect the vacuum hose from R port of the EGR
vacuum modulator and connect R port directly to the
intake manifold with another hose.
(d) Check that the vacuum gauge indicates high vacuum
at 3,500 rpm.
NOTE: As a large amount of EGR gas enters, the engir
will misfire slightly at this time.
(e) Disconnect the vacuum gauge and reconnect the
vacuum hoses to the proper locations.