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

E.C.C.S. CHART
Exhaust gas sensor t
b
Throttle valve switch -b
VG30E Engine (Without turbocharger)
ECCS
control
unit
Crank angle sensor
%el pump control Fuel pump
Air conditioner switch 1 t
Battery voltage
- I
Injectors Fuel injection &
mixture ratio control
VI 1
1
Ignition timing control Power transistor
Idle-up control Idle-up solenoid valve
E G R control E G R control solenoid valve
-1 I
Inspection lamps ixhaust gas sensor
nonitor
& self-diamosis
EF & EC-6

E. C. C.S. CHART
VG30ET Engine (With turbocharger)
Air flow meter c
Cylinder head temperature sensor b
b
Ignition switch b
Throttle valve switch I b
b
Park/Neutral switch
Air conditioner switch I
b
E C C.S
control
unit
b
Injectors Fuel injection &
mixture ratio control
--I
Ignition timing control Power transistor
-dI Auxiliary air control
(A A
C ) valve Idle speed control
I YL
E G R control E G R control solenoid valve
Fuel pump control Fuel pump
Inspection lamps ixhaust gas sensor
nonitor
& self diagnosis I
EF & EC-7

E.C.C.S. DESCRIPTION
E.C.C.S.
E C C.S. CONTROL UNIT
The E C C S control unit consists of a micro-
computer, connectors for signal input and output
and power supply, inspection lamps and diagnostic
mode selector The control unit controls the
amount
of fuel that is injected, ignition timing, idle
speed,
E G R , fuel pump operation, and feedback
of the mixture ratio
SEF611 B
CRANK ANGLE SENSOR
Crank angle sensor is a basic signal sensor for the
entire
E C C S It monitors engine speed and piston
position, and
it sends signals to the E C C S con-
trol unit for control of
fuel injection, ignition
timing, idle speed, fuel pump operation and
E G R
operation.
rnponents
Crank angle sensor has rotor plate and wave form-
ing circuit Rotor plate has
360 slits for 1" signal
(engine speed signal) and
6 slits for 120" signal
(crank angle signal) Light Emitting Diodes
(L
E D ) and Photo Diodes are built into wave
forming circuit
When
signal rotor plate passes the space between
the
L E D and Photo Diode, the slit of the signal
rotor plate alternately cuts the light which
is sent
to
the photo diode from the L E D This causes an
alternative voltage and
it is then converted into an
on-otf pulse by the wave forming circuit, which IS
sent to the control unit
Sealed mwr
Rotor head
.-- ? Lighremitring -. - diode 'I- 1- . ;-- , -
. A. -7. l.lll- i:--, .J
- I -, _,- I- ..
. ir- .I
4,,
Phatodlodel fi-. h- 1 ,h
Wave forming-' circurt '-Rotor piate
SEFBlJB
Rotor plate
SEF614B
EF & EC-13

E.C.C.S. DESCRIPTION
E.C.C.S. Components (Cont'd)
A
Air flow meter 0.
C
AIR FLOW METER
The air flow meter measures the mass flowrate of
intake air. Measurements are made in such
a man-
ner
that the control circuit emits an electrical out-
put signal
in relation to the amount of heat dissi-
pated from the hot wire placed
in the stream of
intake
air.
E F I relay
Battery source
Output voltage
Variable resistor
25 unit Ground
Self-cleaning ignition switch
Ground
El -
-
6- 31 27 35 1
w30 ECCS 6 comroi
F- 12 34 -
-
I SEF615B
SEFSlSB
The air flowing around the hot wire removes the
heat from
the hot wire The temperature of the hot
wire
is very sensitive to the mass flowrate of the
air.
The higher the temperature of the hot wire, the
higher
its resistance value This change in the
temperature (or. resistance)
IS determined by the
mass flowrate of the air. The control circuit
ac-
curately regulates current (I) in relation to the
varying resistance value
(RH) so that VA always
equals VB The air flow meter transmits an output
for voltage
VA to the control unit where the
output
is convened into an intake air signal.
I
Temperature compensation resistor
twire
Hot wore reststance
Temperature campenration resistance RA. RB Constant reSiiIanCe
RH RK
SEFS17B
I
EF & EC-14

E. C. C. S. DESCRIPTION
E.C.C.S. Corn
FUEL TEMPERATURE SENSOR
The fuel temperature sensor is built into the pres-
sure regulator, and senses fuel temperature When
the fuel temperature
IS higher than the specified
level, the
E C C S control unit enriches fuel inject-
ed
Pressure regulator
Fuel temprature $ens
SEF625B
Do not remove fuel temperature sensor from pres-
sure regulator. Always replace as
an assembly.
DETONATION SENSOR (VG30ET engine only)
The detonation sensor
is attached to the cylinder
block and senses engine knocking conditions
A knocking vibration from the cylinder block is
applied as pressure to the piezoelectric element
This vibrational pressure
IS then converted into a
voltage signal which is delivered as output
Reed plate ,, ,-Weight
rTerminal
-.
Piezoelectric element
SEFSZSB
/-
FUEL INJECTOR
The
fuel injector is a small, precision solenoid
valve As the
E C C S control unit outputs an in-
lnents (Cont’d)
jection signal to each fuel injector, the coil built
into the injector pulls the needle valve back, and
fuel
is injected through the nozzle to intake mani-
fold The amount of fuel injected
is controlled by
the
E C C S control unit as an injection pulse
duration
<-Nozzle

LNeedle valve
SEF627B
POWER TRANSISTOR
The ignition signal from the
E C C S control unit
is amplified by the power transistor, which con-
nects and disconnects the coil primary circuit to
induce the proper high voltage in the secondary
circuit
SEFSZBB
IGNITION COIL
The ignition coil
IS a mold type
EF & EC-17

E. C. C. S. DESCRIPTION
Ignition Timing Control
Engine speed and piston position Crank angle sensor
Amount of intake air Air flow meter
Temperature of engine Cylinder head temperature sensor
Throttle valve idle position
Vehicle speed Vehicle speed sensor (VG30ETl 1 I I
Start signal Ignition switch
Engine knocking Detonation sensor
Battery voltage Battery ~
Ignition
timing is controlled, corresponding to the
engine operating conditions, by the
E C C S con-
trol unit that
is, as the optimum ignition timing in
each driving condition has been pre-programmed in
the control unit, the ignition timing
IS determined
by electrical signals processed in the unit
The signal from
E C C S control unit is trans-
mitted to power transistor, and controls ignition
timing
The retard system by detonation sensor
is designed
only for emergencies on VG30ET engines. The
basic ignition timing
is pre-programmed within the
anti-knocking zone, even
if recommended fuel is
used under dry conditions Consequently, the
retard system does not operate under normal
driving conditions
However,
if there engine knocking occurs, the
detonation sensor monitors knocking condition
and the signal is transmitted to the E.C.C S
control unit After receiving it, the control unit
retards the ignition timing to avoid the knocking
condition
Power transistor
EF & EC-23

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

E. C. C. S. DESCRIPTION
Start signal ’ Ignition switch
Throttle valve idle position
Neutral position t
Battery voltage Battery
Idle Speed Control (VG30ET engine)
Engine speed
Engine temperature
ECCS
control
Unlt
-
The idle speed is controlled by the E.C C S. control
unit, corresponding to the engine operating condi-
tions
The E C C S control unit senses the engine
condition and determines the best idle speed
at
each cylinder head temperature and gear position
The control unit then sends an electronic signal
corresponding
to the difference between the best
idle speed and the actual idle speed to the A A C.
valve.
I
,/ lAiC”ON”1 -‘I E .. -
P - 0 E 4 1 - - - -L- - - - - - lZN)
500 w
LAiT (”0”. A/C ”ON1
I -20 0 20 40 60 80 1M) 14) I321 168) 11041 1140) 1176) (212)
Cylinder head ternprature “C (OF1
SEF641B
Auxiliary air control valve
EF & EC-25

E.C.C.S. DESCRIPTION
FUELPUMP ~
FUEL PUMP RELAY
Fuel Pump Control
108
ECCS
CONTROL UNIT
Engine speed --r
Engine temperature
control Fuel pump Start signal
Ignition
switch
position Engine
condition
Throttle valve idle position
Fuel pump Fuel pump
relay operation
Battery voltage Battery
Starting ON
ON for 30 Operates
seconds
Fuel pump voltage control
The fuel pump is controlled by the E C C S con-
trol unit adjusting the voltage supplied to the fuel
pump
Conditions
5 seconds after ignition switch is
turned to ON
Engine cranking
25 5 seconds after engine stan
[above 50°C (122°F)1
Engine temp above 90°C (194OF)
Engine temp below 10°C (50°F)
Except above
Voltage
Approximately
134 [VI
94-134 [Vl'l,
10 1 - 13 4 [VI '2
'1 VG30E engine
"2 VG30ET engine
I SEF643B
Operates for
I OFF I 5 seconds Stopped
I Running I OFF I Operates
Stops in 1
I I I second After stall OFF
EF %t EC-217

DIAGNOSTIC PROCEDURE
Caution
a. Before connecting or disconnecting E C C S
b
C
d
e
harness connector to or from any E C.C S.
unit, be sure to turn the ignition switch to the
"OFF" position and disconnect the negative
battery terminal
Otherwise, there may
be damage to control
unit
Do not attempt to disassemble any E C C S
component parts. To conduct electrical checks
on these component parts, closely follow the
steps outlined under "ELECTRONIC CON-
TROL SYSTEM INSPECTI0N"on pages EF
&
EC-43 through EF & EC-59.
When conducting self-diagnosing, follow the
steps outlined under "SELF-DIAGNOSIS" on
pages EF
& EC-35 through EF & EC-42 in
order to obtain accurate diagnosing results
After selfdiagnosing has been completed, erase
the memory properly
Always turn the diagnosis mode selector care-
fully using
a screwdriver If it is turned forci-
bly,
it may be damaged, resulting in the inabili-
ty to perform the self-diagnosing or to monitor
the mixture ratio
Before troubleshooting, ensure that
all harness
connectors are secure.
EF & EC-28