power steering NISSAN 300ZX 1984 Z31 Engine Fuel And Emission Control System Workshop Manual

E. C. C. S. DESCRIPTION
E.C.C.S. Corn1
AUXILIARY AIR CONTROL (A.A.C 1 VALVE
(VG30ET
engine)
The
A A C valve is attached to the intake collec-
tor The E C CS control unit actuates AAC
valve by ON/OFF pulse of approximately 160 Hz
The longer that ON duty is left on, the larger the
amount of
air that will flow through the A A C
valve
1
AV SEF630B
IDLE-UP SOLENOID VALVE (VG30E engine)
The idle-up solenoid valve is attached to the intake
collector The solenoid valve actuates to stabilize
idle speed when engine load
is heavy because of
electric load, power steering oil pump, etc.
7
idle speed adiuning screw
ldleup solenoid valve
SEF631 B
FICDJ solenoid valve
F I C D adjusling screw
nents (Cont'd)
E G R CONTROL VALVE
The E G R. control valve controls the quantity of
exhaust
gas to be led to the intake manifold
through vertical movement of the taper valve con-
nected to the diaphragm, to which vacuum
IS
applied in response to the opening of the throttle
valve.
SEF632B
When installing the E.G.R. guide tube, be careful
of its direction. Otherwise the distribution effi-
ciency of the exhaust gas will be reduced.
SEF689B
EF 8i EC-18

E.C.C.S. DESCRIPTION
Battery voltage Battery
~-
Headlarnp switch Load signal
Cooling fan switch
Power steering oil pressure switch
Idle-up Control (VG30E engine)
Start signal Ignition switch
ECCS
control
unit
The idle speed is compensated by the E C C S
control unit to prevent rough idle when any of the
following conditions
are met
The control unit senses the idle condition, and
determines
ON/OFF signal The signal from con-
trol unit
is transmitted to the idle-uD solenoid valve
to stabilize idle speed.
Condition
During engine start
20 seconds after engine start
Battery voltage is below 12V
Headlarnp switch ON
Cooling fan switch ON
Power steering oil pressure switch ON
Except above
Idle-up solenoid
operation
ON
OFF
EF 8t EC-24

DIAGNOSTIC PROCEDURE
Driveabil
1. Inspect engine and E C C.S. for air leaks,
proper electrical connections, etc
1) Check all hoses and ducts for air leaks
2) Check air cleaner for clogging
3) Check harness connectors for proper connec-
tions
4) Check ignition wiring
5) Check gaskets for leaks at all air intake com-
ponents
6) Check E G.R valve operation
7) Check air regulator operation
2 Perform E C C S self-diagnosis
Follow the procedure in E CCS SELF-
DIAGNOSIS (Page EF & EC-35)
3 Check idle speed and ignition timing
a. Prepare the following conditions:
Headlampswitch' OFF
Heater blower: OFF
Air conditioner switch: OFF
Front wheel (Power steering model):
KEEP STRAIGHT AHEAD
b. Warm engine to operating temperature.
Check
and adjust as follows
[VG30E engine (Without turbocharger)]
1) Stop engine and disconnect idle-up solenoid
valve harness connector
Idle-up solenoid
2) Start engine and race engine two or three times
under no-load, then run engine
at idle speed
(Cont'd)
3) Check idle speed
M/T & A/T (in "D" position)
700250 rpm at sea level
650250 rpm at high altitude condition
If necessary, adjust to the specified
speed by
turning idle speed adjusting screw
I, SEF6456
4) Stop engine and connect idle-up solenoid valve
harness connector
5) Start engine and check ignition timing with
a
timing light
20ai2" B.T.D.C.
If necessary, adjust ignition
timing by turning
distributor
[VG30ET engine (With turbocharger)]
1) Race engine two or three times under no-load,
then run engine at idle speed
2) Check idle speed.
M/T: 70W50rpm
A/T: 650k50 rpm (in "D" position)
EF & EC-30