sensor NISSAN 300ZX 1984 Z31 Engine Fuel And Emission Control System User Guide

E.C.C.S. DESCRIPTION
Engine speed Crank angle sensor c
Engine temperature ’
Throttle valve idle position Throttle valve switch
Start signal
Exhaust Gas Recirculation (E.G. R.) Control
ECCS
control
unit
EGR
E G R control sclenoid valv
Throttle valve witch
C lhnder head era1“re semor
Crank angle sensor
OPERATION
In the exhaust gas recirculation system, some of
the exhaust
gas is returned to the combustion
chamber to lower
the flame temperature during
combustion This results
in a reduction of the
nitrogen oxide density in the exhaust
gas.
When the E G.R control valve is open, some of the
exhaust
gas is led from the exhaust manifold to the
E G.R. tube The exhaust gas is then regulated by
E.G.R. valve, and
is introduced into the intake
manifold.
The signal from the E C C.S control unit is sent to
the
E.G.R control solenoid valve, which cuts the
vacuum line for the E G.R control valve when any
of the following conditions are met
-Start signal
SE F642 B
I Operation
E G R system I
Condition E G R control
solenoid
Engine starting
Throttle valve switch
“ON”
Low engine temperature Does not
Engine speed
below 900 rpm
above 3,200 rpm
Operates Except above
EF & EC-26

DIAGNOSTIC PROCEDURE
Driveabili
If out of specification, adjust as follows
ness connector
a Stop engine and disconnect A A C valve har-
SEF646B
b Start engine and adjust engine speed by turning
idle speed adjusting screw
M/T: 650 rpm
A/T. 600 rpm (in "D" position)
c. Stop engine and connect A.A.C. valve har-
ness connector Then
start engine
d Make sure that idle speed
is in the specified
range.
3) Check ignition timing with a timing light
ZO"r2" B.T.D.C.
If necessary, adjust ignition timing by turning
distributor
Perform mixture ratio feedback
system inspec-
tion Follow the procedure
in MIXTURE RATIO
4
(Cont'd)
FEEDBACK SYSTEM INSPECTION (Page EF
lk EC-60)
5 Perform driveability test
Evaluate effectiveness of adjustments by driv-
ing vehicle If unsatisfactory, proceed to step
6
6
Perform electronic control system inspection
Check the following using circuit tester
Injector circuits
Air regulator circuit
E G R control solenoid circuit
E xhaust gas sensor heater circuit
Follow the procedure in ELECTRONIC CON-
TROL SYSTEM INSPECTION (Page EF
& EC-
43)
7 Check idle mixture ratio
1) Warm up engine to operating temperature
2) Turn off engine and disconnect throttle valve
switch harness connector
3) Verify that the diagnosis mode selector is
turned fully counterclockwise
4) Start engine and verify that engine IS still at
operating temperature.
5) Race engine two or three times under no-load,
then run engine
at idle speed
6) Look at inspection lamps (red and green)
SEF648B
When both inspection lamps blink, it indicates
that the idle mixture ratio IS correct.
EF & EC-31

SELF-DIAGNOSIS
Self-diagni
The self-diagnostic system determines malfunctions
of signal systems such as sensors, actuators, and
wire harnesses based on the status of the input
signals received by the
E C C S control unit
A malfunction is displayed by both the red and
green
L E D s (Light Emitting Diodes).
Basically, self-diagnosis
is always performed when
the power
is furnished to the E C C S control
unit The self-diagnosis results
are retained in the
memory chip of the
E C C S control unit and are
displayed only when the diagnosis mode selector
(located on
the side of the E C C S. control unit) is
turned fully clockwise
The self-diagnostic system
is provided with func-
tions which display malfunctions being checked
as well as those which are stored in the memory
In
this sense, it is very effective in determing an
"intermittent" malfunction The results which
is
or was stored in the memory can be erased by
following the steps specified
A malfunctioning area is determined by the num-
ber of blinks of both the
red and green L E D s
First, the red L E D blinks and the green follows
The red L E D refers to the tenth digit while the
green
one refers to the unit digit. For example,
when the red L
E D. blinks three times and the
green
L E.D blinks twice, this implies number
"32" In this way, all problems are classified by
code numbers.
inspection lamps1 Diagnosis mode
SEF6508
Judging the selfdiagnosis results
1 When the ignition switch is turned "ON",
the diagnostic system judges
a malfunction
tic System
until the specified input signal is entered and
detected
as 0 K
(These input signals are not stored in the
memory
)
1) Vehicle speed sensor circuit (VG30ET engine)
When the vehicle speed exceeds
10 km/h
(6 MPH) and its corresponding signal is entered
2) Throttle valve switch (idle switch) circuit,
neutral switch circuit (VG30ET engine) and
air
conditioner switch circuit
After the ignition switch
is turned "ON" and
"ON-OFF"
signals from each switch are
entered
3) Start signal
After the engine has started and when start
signals "ON" and then "OFF" are entered
2 After the self-diagnostic system has detected
a malfunction, it continues to provide a mal-
function display until the memory
is erased
properly by the sepcified steps
1) Crank angle sensor circuit
When 1" or 120" signal is not entered after
the engine has started
When either 1" or 120" signal is not entered
often enough
2) Air flow meter circuit
When the air flow meter produces an abnormal-
ly high output voltage with the engine off
When the air flow meter produces an abnormal-
ly low output voltage with the engine running.
3) Cylinder head temperature sensor circuit
When the cricuit
is shorted or open
4) Ignition signal
When an ignition signal
is not produced on the
primary winding of the ignition coil after
the
engine has started
5) Fuel pump circuit
When current flowing through the E
C C.S
control
unit to drive the fuel pump IS too
small or too large while the engine
is operating.
6) Detonation sensor circuit (VG30ET engine)
When the circuit
is shorted with the engine
operating
at a speed of above 2,000 rpms
When the circuit is shorted or open
7) Fuel temperature sensor circuit
EF & EC-35

SELF-DIAGNOSIS
-Self-diagnostic System (Cont'd)-
CAUTION.
a. Always turn the diagnosis mode selector
carefully using
a screwdriver Do not press
hard to turn. Otherwise, the selector may be
damaged
b. When the engine fails to start, crank the engine
more
than two seconds before starting the
self-diagnosing.
c. Before starting the self-diagnosing, do not erase
the stored memory. Doing
so will reduce
the self-diagnosis function considerably.
d. After a malfunctioning area has been corrected,
be sure to erase the memory
e. The self-diagnosed results are retained in the
memory by a small current flow from the
battery. Disconnecting the battery cable
or
the E.C.C.S.'s 15-pin connector erases the
memory stored. Always perform the
self-
diagnosing regarding "intermittent" checks
before disconnecting.
The crank
angle sensor signal plays an impor-
tant role in the E.C.C.S. A malfunctioning
sensor
is sometimes accompanied by a display
which shows malfunctions in other signal
systems.
In such a case, always start with
checking the crank angle sensor.
f
EF & EC-36

SELF-DIAGNOSIS
Decoding Chart
I Code No 11
I ked Green
00
1 CodeNo 12
I 'Red Green
0 00
Crank angle sensor circuit IS malfunctioning
Air flow meter circuit IS
malfunctioning 1
See page
EF & EC43
SEF6578
EF & EC44 & 45
1
SEF658B II
I CodeNo 13 I
Cylinder head temperature sensor clrcuit IS malfunctioning
See page EF & EC-46
SEF659B II
Vehtcle speed sensor circuit IS malfunctioning (VG30ET engine)
See page
EF & EC47
Id SEF660B
EF & EC-39

SELF-DIAGNOSIS
Decoding Chart (Cont'd)
AK condnioner svstem I 16 malfunctioning
Code No 31 ~~
A ~ Green , ?/=%$== =- ~~ 0 Red
000 0
SEF665B
Starter rlgnal IS malfunctioning
Code
No 32
I2 SEF666B
CodeNo 34
Detonation sensor Circuit IS malfunc
tiontng IVG30ET enginel
See page
EF&EC52
SEF667B I ~
See
page EF & EC-53
I
Fuel temperature sensor circuit IS malfunnmnlng
Code No 41
=-a
Red Green
0
II SEF668B
EF & EC-41

ELECTRONIC CONTROL SYSTEM INSPECTION
Check harness between crank angle sensor and
control unit
PREPARATION
Before checking the following items, ensure that each connector IS securely connected
N G ~ harness
Repair or replace harness and high tension cable
or dust
Visually check crank angle sensor for damage 1 “--+I Replace crank angle sensor
OK
Replace E C C S control unit 1
EF & EC-43

ELECTRONIC CONTROL SYSTEM INSPECTION
@ Cylinder head temperature sensor (Code No 13)
Disconnect 16-pin connector and measure the
resistance between terminals @and
@$
Dip the sensor into water maintained at a temper-
ature
of 20°C (68°F). 80°C (176°F). etc, and read
its resistance
2
I lo; - - c4
- ;2
c 66
g2
m : io3 u
z4 *
102
-30 0 40 80 120 (-221 I321 (1041 11781 (2481 -20 20 60 100 130 (-41 (681 (1401 (2121 (2661
Temperature "C (OF) -
SEF677B
(OK I N G.
Replace cylinder head temperature sensor
EF & EC-46

ELECTRONIC CONTROL SYSTEM INSPECTION
:@ Vehicle speed sensor (Code No. 14)
Disconnect speedometer cable from transmission
I
SEF678B
I
Disconnect 16-pin connector from E C C S control
unit and check continuity between terminal
@
and ground while slowly turning speedometer cable
ONIOFF puk should be detected n
(Refer to “METER AND GAUGES in
Replace E C C S control unit
EF & EC-4‘7

ELECTRONIC CONTROL SYSTEM INSPECTION
@ Start signal (Code No. 32)
Repair or replace NG Check starting system 1
OK
20-pin connector and measure voltage between
terminal and ground
Emery voltage
SE F691 B I OK I
Replace E C C S control unit
@ Detonation sensor (Code No. 34)
1 ) Disconnect detonation sensor harness connector
2)
Start engine and increase engine speed while
checking ignition timing
3) Check if ignition timing retards by 5 degrees when
engine speed increases when engine speed increases
more than 2,000 rpm
I SEF692B
Repair harness
(Refer to
EL section I
Replace E C.C.S control unit
Repair harness N.G OK1
Replace detonation sensor.
EF & EC-52