1987 NISSAN PULSAR ECU

108 Fuel and Engine Management


Installed view of the control unit with the passengers seat removed.
(2) Secure the Mem-Cal unit retaining clips.
Ensure that the clips locate into the Mem-Cal unit. (3) When installing a new control unit, transfer
the identification and bar code label to the new
control unit. (4) Ensure that the control unit wiring connec-
tors are securely installed to the control unit. (5) Activate the self diagnosis codes. If code 51
is displayed or the Check Engine warning lamp is
constantly illuminated, the Mem-Cal unit is not fully
installed. If the Mem-Cal uni t is installed correctly, a
fault in the Mem-Cal unit is indicated. Renew the
Mem-Cal unit as previously described.
To Check Power Supply and Earth Circuit

(1) Disconnect the control unit wiring connec-
tors and check for voltage at terminals B1 and C16.

If there is no voltage check the fusible link which
is located third from the front in the fusible link
connecting block. If the fu sible link is serviceable,
repair the open circuit in the wiring harness.

(2) Check for continuity to earth on terminals
A12, D1, D6 and also D3 and D10 on 1.8 liter
engines.

If there is no continuity check the earth connec-
tions at the right hand rear cylinder head bolts. If the
connections are clean and secure, repair the open
circuit in the wiring harness.

MEM-CAL UNIT
To Test - Code 51

If code 51 is displayed during the self diagnosis
test procedure, pr oceed as follows:

(1) Check that the Mem-Cal unit is fully inserted
in the control unit. (2) Erase the fault code memory and retest for
fault codes. (3) If code 51 is still displayed, renew the
Mem-Cal unit.
(4) Erase the fault code memory and retest for
fault codes. (5) If code 51 is still displayed, renew the control
unit.
To Remove and Install

The Mem-Cal unit is incorporated within the
control unit. Refer to the previous heading for the
removal and installation procedure.

FUEL PUMP AND EGI RELAYS
To Remove and Install
(1) Disconnect the negative battery terminals.
(2) Remove the fuse panel cover which is lo-
cated adjacent to the steering column under the
instrument cluster. (3) Remove the spare fuse holder from the fuse
panel and remove the releva nt relay from the connec-
tor. Installation is a reversal of the removal procedure.


View showing the location of the EGI and fuel pump
relays.
To Test Relays
NOTE: When testing the fuel pump relay
circuit ensure that th e EGI relay is service-
able and installed to the relay connector

(1) Remove the relevant relay as previously
described. (2) Using an ohmmeter, check for continuity
between terminals 1 and 2, and 3 and 5. Continuity should exist be tween terminals 1 and 2
but should not exist between terminals 3 and 5.

(3) Using suitable jumper leads, apply 12 volts
to terminal 1 and connect terminal 2 to a good earth
point. (4) Connect the ohmmeter between terminals 3
and 5. Continuity should exist. If continuity does not
exist, renew the relay.

110 Fuel and Engine Management
originally performed, an intermittent fault is indi-
cated. Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth wires are secure.
(4) Disconnect the wiring connector from the
coolant temperature sensor. (5) With the ignition switched On, measure the
voltage across the terminals on the coolant tempera-
ture sensor wiring connector. The voltage should be
4-6 volts.
If the voltage is below 4 volts, proceed to opera-
tion (9).

If the voltage is as specified, proceed as follows.
(6) Remove the coolant temperature sensor
from the vehicle. (7) Connect an ohmmeter to the coolant temper-
ature sensor terminals. (8) Immerse the meta1 end of the coolant
tem-
perature sensor in a 50/50 mixture of glycol and iced
water at a temperature of 0 deg C. The resistance
should be 6 000 ohms. Slowly heat the mixture and measure the resis-
tance of the coolant temperature sensor at the follow-
ing temperatures. Compare the results with the spec-
ified values:

0 d e g C ................................................. 6 000 ohms
20 deg C .................................................. 2 500 ohms
30 deg C .................................................. 1 800 ohms
40 deg C.................................................. 1 200 ohms
70 deg C .......................................................450 ohms
90 degC .......................................................250 ohms
100 deg C.....................................................190 ohms
110 deg C.....................................................110 ohms
If the resistances obtained are not as specified at
any of the given temperatures, renew the coolant
temperature sensor and retest for fault codes.

(9) Disconnect the control unit wiring connec-
tors.
(10) Check the wiring harness for shorts and
continuity between the coolant temperature sensor
wiring connector terminals and the control unit wiring
connector terminals C10 and D2. Repair or renew the
wiring harness as necessary.
Also check the control unit terminals for damage.
If no fault is found, renew the control unit and
retest for fault codes.

To Remove and Install
(1) Disconnect the negative battery terminal.
(2) Disconnect the wiring connector from the
coolant temperature sensor.
(3) Drain the coolant as described in the Cooling
and Heating Systems section to a level below the
sensor.
(4) Unscrew the sensor from the thermostat
housing. Installation is a reversal of the removal procedure
with attention to the following points;

(1) Apply Loctite 675 or a similar conductive
sealer to the threads of th e sensor. Tighten the sensor
to the specified torque.
(2) Fill the cooling system with the correct
mixture of water and inhibitor as described in the
Cooling and Heating Systems section. (3) Ensure that the wiring connector is clean and
secure.
THROTTLE POSITION SENSOR
To Test - Codes 21 and 22

NOTE: The following test procedure as-
sumes that fault codes 21 or 22 have been
displayed during the se lf diagnosis test pro-
cedure. If no codes have been displayed but
the operation of the throttle position sensor
is suspect, begin the test procedure at oper-
ation (24).

(1) Erase the self diagnosis code memory as
previously described.
(2) Start and run the engine at idle speed for 60
seconds or until the ECM warning lamp lights. If the engine will not start, disconnect the throttle
position sensor wiring co nnector and proceed to
operation (8). .

(3) With the engine id ling, quickly increase the
engine speed to 3 000 rpm and return to idle.

If the ECM warning lamp remains illuminated,
proceed to operation (4).

If the ECM warning lamp extinguishes, an inter-
mittent fault is indicated. Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth wires are secure.
(4) Stop the engine, switch the ignition On and
connect a jumper lead between terminals A and B on
the diagnostic link connect or. Note any fault codes
displayed.

If codes 21 or 22 are displayed, proceed as
follows.

(5) Remove the jumper lead from the diagnostic
link connector. (6) Erase the self diagnosis codes as previously
described. (7) Disconnect the wiring connector from the
throttle position sensor. If code 22 was displayed in operation (4), proceed
to operation (13).

If code 21 was displayed in operation (4), proceed
as follows.

(8) Start and run the engine at idle speed for 2
minutes or until the ECM warning lamp lights. If the
engine will not start, pr oceed to operation (11).
(9) Stop the engine, switch the ignition On and
connect a jumper lead between terminals A and B on

112 Fuel and Engine Management
If the voltage does not increase as specified, renew
the throttle position sensor.

If the voltage is as specified, proceed as follows.
(28) With the ignition switched On and the
throttle valve held fully open, measure the voltage at
control unit wiring connector terminal C13. The
voltage should be above 4 volts.

If the voltage is below 4 volts, renew the throttle
position sensor.

To Remove and Install
(1) Disconnect the negative battery terminal.
(2) On 1.6 liter engines, remove the air cleaner
assembly as previously described. (3) Disconnect the throttle position sensor wir-
ing connector. (4) Remove the throttle position sensor retain-
ing screws and remove the throttle position sensor
from the throttle body. Installation is a reversal of the removal procedure
with attention to the following points:

(1) Ensure that the throttle valve is in the fully
closed position. (2) Tighten the retaining screws securely and
install the wiring connector.

View of the throttle positi on sensor removed from the
throttle body assembly.
MANIFOLD AIR TEMPERATURE (MAT)
SENSOR - 1.8 LITRE ENGINE

To Test - Codes 23 and 25
(1) Erase the self diagnosis code memory as
previously described.
(2) Start and run the engine for 2 minutes or
until the ECM warning lamp lights. (3) Stop the engine, switch the ignition On and
connect a jumper lead between terminals A and B on
the diagnostic link connector . Note any fault codes
displayed. If codes 23 or 25 are displayed, proceed to
operation (4).

If codes 23 or 25 are not displayed but were
displayed when the self diagnosis test procedure was
originally performed, an intermittent fault is indi-
cated. Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth wires are secure.
(4) Disconnect the wiring connector from the
MAT sensor. (5) With the ignition switched On, measure the
voltage across the terminals on the MAT sensor wiring
connector. The voltage s hould be 4-6 volts.
If the voltage is below 4 volts, proceed to opera-
tion (9).

If the voltage is as specified, proceed as follows.
(6) Remove the MAT sensor from the engine.
(7) Connect an ohmmeter to the MAT sensor
terminals. (8) Immerse the metal end of the MAT sensor in
a container of iced water at a temperature of 4 deg C.
The resistance should be 7 500 ohms. Slowly heat the water and measure the resistance
of the MAT sensor at the following temperatures.
Compare the results with the specified values:

20 deg C .................................................. 3 400 ohms
38 deg C....................................................1 800 ohms
70 degC ...................................................... 450 ohms
100 deg C.................................................... 185 ohms
If the resistances obtained are not close to the
specified figures at any of the given temperatures,
renew the MAT sensor and retest for fault codes.

(9) Disconnect the control unit wiring connec-
tors. (10) Check the wiring harness between the MAT
sensor wiring connector and the control unit wiring
connector terminals C12 and A11 for shorts and
continuity. Also check the control unit terminals for
damage. Repair or renew the wiring harness as necessary.
If no fault is found, renew the control unit and
retest for fault codes.

To Remove and Install
(1) Disconnect the negative battery terminal.
Installed view of the MAT sensor. 1.8 liter engine.

Fuel and Engine Management 113
(2) Disconnect the wiring connector from the
MAT sensor.

(3) Unscrew the sensor from the inlet manifold.
Installation is a reversal of the removal procedure

with attention to the following points:
(1) Apply Loctite 567 or a similar conductive
sealer to the threads of th e sensor. Tighten the sensor
to the specified torque. (2) Ensure that the wiring connector is clean and
tight.
OXYGEN SENSOR

To Test - Code 13
(1) Run the engine until the normal operating
temperature is obtained. (2) With the ignition switched Off, connect a
jumper lead between terminals A and B on the
diagnostic link connector.
(3) Start and run the engi ne at approximately
1 600-1 800 rpm for 2 minutes and note the ECM
warning lamp.
If the ECM warning lamp flashes at the rate of
twice per second, proceed to operation (5).

If the ECM warning lamp flashes at the rate of
once per second or slower, proceed as follows.

(4) Remove the jumper lead from the diagnostic
link connector and run th e engine above 2 000 rpm
for 2 minutes, noting the ECM warning lamp.

If the ECM warning lamp lights, stop the engine,
switch the ignition On and connect a jumper lead
between terminals A and B on the diagnostic link
connector. If code 13 is displayed proceed to opera-
tion (5).

If the ECM warning lamp does not light, an
intermittent fault is indicated. Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure.
(b) Check that all earth wires are secure.
(5) Switch the ignition Off and disconnect the
oxygen sensor wiring connector. Using a jumper lead
connect the oxygen sensor wiring connector to a
suitable engine earth. (6) Start and run the engi ne at approximately
1 600-1 800 rpm and note the ECM warning lamp.
The lamp may flash for a few seconds but should then
extinguish for at least 30 seconds.
If the ECM warning lamp functions as described,
proceed to operation (7).

If the ECM warning lamp does not function as
described proceed as follows:

(a) Check the wiring harness between the oxygen
sensor wiring connector and the control unit wiring
connector D7 for open circuits. Repair or renew the
wiring harness as necessary.

{b) Check the earth circuit between the control
unit wiring connect D6 and the right rear cylinder
head bolts. Repair or renew the wiring harness as
necessary.

(c) If no fault is found in (a) and (b) renew the
control unit and retest for fault codes.

(7) Check the wiring harness earth circuit be-
tween the control unit wiring connector D6 and the
right rear cylinder head bolts. Repair or renew the
wiring harness as necessary.

If no fault is found, thoroughly check the oxygen
sensor connector. If the conne ctor is not faulty, renew
the oxygen sensor.

To Test - Code 44
(1) Run the engine until normal operating tem-
perature is attained.
(2) With the ignition switched Off, connect a
jumper lead between terminals A and B on the
diagnostic link connector. (3) Start and run the engi ne at approximately
1 600-1 800 rpm for 2 minutes and note the ECM
warning lamp. If the ECM warning lamp is off more than on or
flashes at the rate of twice per second, proceed to
operation (4).

If the ECM warning lamp flashes evenly at the
rate of once per second an intermittent fault is
indicated. Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth wires are secure.
(4) Switch the engine Off and disconnect the
oxygen sensor wiring connector.
(5) Start and run the engine at 1 600-1 800 rpm
for at least 30 seconds and note the ECM warning
lamp. If the ECM warning lamp flashes at the rate of
twice per second procee d to operation (6).

If the ECM warning lamp extinguishes for at least
30 seconds, check the wiring harness between the
oxygen sensor wiring connector and the control unit
wiring connector terminal D7 for shorts to earth.

Repair or renew the wiring harness as necessary.
If no fault can be found in the wiring harness, renew
the control unit.

Installed view of the oxygen sensor.

114 Fuel and Engine Management
(6) Check the vehicle for the following:
(a) Low fuel pressure.
(b) Contaminated fuel.
(c) Vacuum leaks at the inlet manifold, engine
vacuum hoses and engine ventilation hoses. (d) Exhaust manifold leaks before the oxygen
sensor. (e) Correct MAP sensor operation.
(f) Blocked oxygen sensor metal vent cover eg.
plugged with mud etc. (g) Fuel injectors) partially blocked. Refer to a
fuel injection specialis t or a Nissan dealer.
If the above items have been checked and no
faults have been found, a faulty oxygen sensor is
indicated. Renew the oxygen sensor, run the engine
and ensure that no fault codes are set.

To Test — Code 45
(1) Run the engine until normal operating tem-
perature is attained. (2) With the ignition switched Off, connect a
jumper lead between terminals B and A on the
diagnostic link connector. (3) Start and run the engine at approximately
1 600-1 800 rpm for 2 minutes and note the ECM
warning lamp. If the ECM warning lamp is on more than off or
flashes at the rate of twice per second, proceed to the
following operation.

If the ECM warning lamp flashes evenly at the
rate of once per second an intermittent fault is
indicated. Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth wires are secure.
(4) Switch the engine Off and disconnect the
oxygen sensor wiring connector. (5) Using a jumper lead, connect the oxygen
sensor wiring connector to a suitable engine earth. (6) Start and run the engine at 1 600-1 800 rpm
and note the ECM warning lamp.
If the ECM warning lamp extinguishes for at least
30 seconds, proceed to operation (7).

If the ECM warning lamp flashes on more than off
or flashes at the rate of twice per second, switch the
engine Off and disconnect the control unit wiring
connectors. Using an ohmmeter, check that there is no
resistance between the co ntrol unit wiring connector
terminal D6 and earth. Repair or renew the wiring as
necessary.

If no fault can be found in the wiring harness,
renew the control unit.

NOTE: The wiring harness for terminal D6
earths through the righ t hand rear cylinder
head bolt.

(7) Check the vehicl e for the following:
(a) High fuel pressure.
(b) Leaking injector(s).
(c) Faulty ignition wiring.
(d) Charcoal canister purge system blocked or
restricted.
(e) Faulty coolant temper ature sensor circuit.
(f) Faulty MAT sensor circuit (1.8 liter engine).
(g) MAP sensor operation.
(h) Throttle position sensor operation.

If the above items have been checked and no
faults have been found, a faulty oxygen sensor is
indicated.

Renew the oxygen sensor, run the engine and
ensure that no fault codes are set.

To Remove and Install
(1) If the engine is cold, run the engine for
approximately two minutes to allow easy oxygen
sensor removal. (2) Disconnect the negative battery terminal and
the oxygen sensor connector.

View of the oxygen sensor removed from the exhaust
manifold.
(3) Remove the exhaust manifold heat shield
retaining bolts and remove the heat shield from the
engine.
(4) Remove the oxygen sensor with a short ring
spanner using care not to damage the sensor wire. Installation is a reversal of the removal procedure
with attention to the following points:

(1) When installing a sensor that has previously
been removed, coat the sen sor threads with anti-seize
compound. Nissan recommend a mixture of liquid
graphite and glass beads. (2) Install the sensor and tighten to the specified
torque. (3) Connect the electrical connector ensuring
that the wiring is secured away from the exhaust. (4) Install the heat shield and tighten the retain-
ing bolts securely. On 1.6 liter engines, ensure that the hot air inlet
tube is located correctly be tween the heat shield and
the air cleaner housing.

(5) Start the engine and check for leaks.
VEHICLE SPEED SENSOR
To Test - Code 24

(1) Check the fuel pump and meter fuses. If the
fuses are serviceable, proceed to operation (5). If a
fuse is blown, rectify the cause and renew the fuse.

Fuel and Engine Management 115
Erase the fault codes and retest for fault codes as
follows:

(2) Start and run the engine until normal oper-
ating temperature is attained. (3) Drive the vehicle at a speed of at least 80
km/h and, with the throttle closed, allow the vehicle to
decelerate until the engine speed is below 1 500 rpm.
NOTE: After rectifying any fault it will be
necessary to retest for fault codes. To test for
Code 24 the vehicle must be driven as
previously described.

(4) Switch the engine Off and connect a jumper
lead between terminals A and B on the diagnostic link
connector. Switch the ignition On and note the fault
codes. If code 24 is displayed proceed as follows. (5) Check the operation of the speedometer and
the instrument cluster warning lamps. If the speed-
ometer only is not functioning, proceed to operation
(13).
If the speedometer and the instrument cluster
warning lamps are not functioning, a fault in the
instrument cluster wiring harness is indicated. Refer
the fault to an auto electrical workshop or a Nissan
dealer.

If the speedometer is functioning, proceed as
follows:

(6) Raise the front of the vehicle and support it
on chassis stands. (7) Place the transaxle in Neutral and switch the
ignition On. (8) With the aid of assistants, slowly spin the
front wheels by hand while backprobing the control
unit wiring connector terminal A10 with a digital
voltmeter to earth. The voltage should alternate from under 1 volt to
over 10 volts.

If the voltmeter readi ng is not as specified,
proceed to operation (9).

If the voltmeter reading is as specified, the vehicle
speed sensor is operating satisfactorily, indicating an
intermittent fault was the cause of the fault code.
Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth c onnections are secure.
(9) Remove the instrument cluster as described
in the Electrical System section. (10) With the ignition switched On, backprobe
the control unit wiring connector terminal A10 with a
voltmeter to earth. The voltage should be over 10
volts. If the voltage is less than specified, check the
wiring harness for shorts to earth between the black
and yellow wire terminal on the instrument cluster
wiring connector and the control unit connector
terminal A10. Repair or renew the wiring harness as
necessary. If no fault can be found, renew the control
unit.

(11) With the ignition switched On, backprobe
the black and yellow wire terminal on the instrument
cluster wiring connector with a voltmeter to earth.
The voltage should be over 10 volts.

If the voltage is less than specified, locate the open
circuit between the instrument cluster black and
yellow wire terminal and the control unit wiring
connector terminal A10. Repair or renew the wiring
harness as necessary.

(12) With a test lamp connected to 12 volts,
backprobe the black wire terminals on the instrument
cluster wiring connectors. The test lamp should light.

If the test lamp does not light locate the open
circuit between the black wire terminals and earth.
Repair or renew the wiring harness as necessary.

If the test lamp does light, renew the signal
divider circuit board which is located in the instru-
ment cluster.

(13) With the ignition switched On and the
engine not running, disconnect the vehicle speed
sensor wiring connector from the harness connector.
(14) With a test lamp connected to earth, probe
the yellow wire terminal on the harness wiring con-
nector. The test lamp should light. If the test lamp does not light, locate the open
circuit between the yellow wi re terminal and the Fuel
Pump fuse. Repair or renew the wiring harness as
necessary.

(15) With a test lamp connected to 12 volts,
probe the black wire terminal on the harness wiring
connector. The test lamp should light.

If the test lamp does not light, locate the open
circuit between the black wire terminal and earth.
Repair or renew the wiring harness as necessary.

(16) Using a voltmeter measure the voltage at the
red wire terminal on the harness wiring connector.

If the voltage is 5-9 volts proceed to operation
(19).

If the voltage is over 9 vol ts proceed to operation
(18).

Installed view of the vehicle speed sensor.

116 Fuel and Engine Management


Rear view of the instrument cluster showing the flexible printed circuit.
If the voltage is under 5 volts proceed as follows.
(17) Check the wiring harness for continuity or
shorts to earth between th e red wire terminal on the
speed sensor harness connector and the green and
black wire terminal on th e instrument cluster wiring
connector.

If no fault can be found check the instrument
cluster printed circuit for continuity or shorts. If no
fault can be found, renew the speedometer and the
signal divider circuit board.

(18) Remove the instrument cluster as described
in the Electrical System se ction and repeat operation
(16).

If the voltage is under 1 volt, check the flexible
printed circuit on the rear of the instrument cluster for
continuity or shorts and re new as necessary. If no fault
can be found, renew the speedometer and the signal
divider circuit board.

(19) Connect the harness connector to the vehicle
speed sensor wiring connector. (20) Raise the front of the vehicle and support it on chassis stands. Place the transaxle in Neutral.

(21) With the aid of assistants, slowly spin the
front wheels by hand while backprobing the brown
wire terminal on the vehicle speed sensor wiring
connector with a voltmeter to earth.

The voltage should alternate between approxi-
mately 1 and 7 volts.

If the voltage is as specif ied, check the flexible
printed circuit on the rear of the instrument cluster for
continuity or shorts. If no fault can be found, renew
the speedometer and the signal divider circuit board.

If the voltage is not as specified, proceed as
follows.

(22) Disconnect the vehicle speed sensor wiring
connector and unscrew the sensor from the speedom-
eter drive housing. (23) Rotate both front wheels in the same direc-
tion and check that the speedometer drive shaft is
turning and does not slip. If the drive shaft does not operate as described,
renew the drive assembly as described in the Manual
or Automatic Transaxle section.

If the drive shaft operates satisfactorily, renew the
vehicle speed sensor.

To Remove and Install
(1) Disconnect the negative battery terminal.
(2) Disconnect the vehicle speed sensor wiring
connector. (3) Unscrew the vehicle speed sensor from the
speedometer drive housing.
Installation is a reversal of the removal procedure
with attention to the following points:

(1) Align the cut-out in the speedometer drive
shaft with the notch in the vehicle speed sensor shaft.
(2) Tighten the vehicle speed sensor securely.

Manual Transaxle and Drive Shafts 131

(19) Renew the rear mainshaft bearing outer race
as follows:

(a) Remove the bolts retaining the rear cover to
the transaxle case. (b) Remove the rear cover. O ring, spacer and
adjusting shim from the transaxle case. Discard the O
ring. (c) Using a suitable punch, tap the bearing outer
race out of the transaxle case. (e) Install the adjusting shim, spacer and a new O
ring to the transaxle case. Install the rear cover and
tighten the retain ing bolts securely.

(20) Renew the front mainshaft bearing outer
race as follows:

(a) Using a suitable puller, pull the outer race
out of the clutch housing.
(b) Ensure that the oil groove in the resin oil
channel is facing the oil pocket in the clutch housing. (c) Install the new outer race to the clutch
housing.
(21) Measure the end float of the input shaft fifth
gear using feeler gauges betw een the fifth gear and the
adjacent gear shoulder. Note the measurement for
later reference.
(22) Dismantle the input shaft as follows:
(a) Remove the snap ring and spacer from the
front of the input shaft. (b) Using a suitable puller, remove the bearing
from the front of the input shaft. Remove the bearing
retainer noting the installed direction. (c) Remove the snap ring from the rear of the
input shaft. (d) Remove the shift retainer, fifth gear synchro
assembly, fifth gear and th e split bearing from the rear
of the input shaft.
(23) Measure the end float of the mainshaft first,
second, third and fourth gears using feeler gauges
between the gear and the adjacent shaft shoulder.
Note the measurements for later reference.
(24) Dismantle the mainshaft as follows:
(a) Remove the front and rear bearing cones
using a suitable puller.


Dismantled view of the mainshaft.
(b) Remove the C ring holder, the C rings and
the thrust washer from the rear of the mainshaft. (c) Using a puller positioned on the fifth gear
rear flange, remove the fifth gear from the mainshaft. (d) Remove the fourth gear , bush and steel ball
from the mainshaft. (e) Remove the third/fourth synchro assembly,
using a suitable puller if necessary. (f) Remove the third gear, bush, steel ball and
second gear from the mainshaft. (g) Remove the first/second synchro assembly,
using a suitable puller if necessary. (h) Remove first gear and the needle roller
bearing from the mainshaft.

(25) Suitably mark the assembled positions of the
synchro assemblies components and remove the
springs from the assemblies.
(26) Slide the sleeves off the hubs and remove the
shift plates.
(27) Arrange the various synchro components
separately to avoid mixing the components on
assembly.
TO CLEAN AND INSPECT

(1) Clean all the components in cleaning solvent
and allow to dry.
(2) Inspect the teeth on all the gears for wear,
pitting and damage. (3) Push each synchro ring onto its respective
gear cone and measure the distance between the
synchro ring and the synchro teeth on the gear. Renew
the synchro ring and/or the gear if the distance is less
than 0.7 mm.
(4) Inspect the shift forks for excessive clearance
in the synchro sleeves and the control fingers. Renew
the forks as necessary if the clearance is excessive. (5) Inspect the components of the control
bracket for wear and damage. Inspect the shift caps
for wear. Renew the control bracket and/or the shift
caps as necessary.
218/680 INPUTSHAFT M AI N B E AF I N G SPACER
Dismantled view of the input shaft.