1987 NISSAN PULSAR check engine

Fuel and Engine Management
(4) MAP sensor faulty or supply hose discon-
nected or blocked: Check the vacuum supply hose.
Check the operation of the MAP sensor.

EXCESSIVE FUEL CONSUMPTION
(1) Blocked air cleaner element: Check the ele-
ment and clean or renew as necessary.
(2) Incorrect fuel pressure: Check the fuel pump
and fuel pressure regulator. (3) Faulty coolant temperature sensor: Check
the connections and operation.
(4) Leaks in the fuel supply system: Check the
connections and components for leakage. (5) Leaking fuel injector(s): Clean or renew the
faulty injector(s). (6) Engine operating temperature too low:
Check the thermostat and electric cooling fan as
described in the Cooling an d Heating Systems section.
2. DESCRIPTION
The engine management system on the range of
vehicles covered by this manual controls the opera-
tion of the ignition system and the fuel system.

The central component of the engine management
system is the electronic control unit (ECU). The con-
trol unit is a micro-computer which controls the igni-
tion timing and the amount of fuel injected according
to signals received from various sensors. As changes
are detected in engine load and speed, coolant tem-
perature, barometric pressure, air temperature (1.8
liter engine), throttle position and vehicle speed, the
control unit alters the ignition timing and the fuel
injection amount to achieve optimum engine effi-
ciency.

The control unit incorporates a self diagnosis
mode which stores and displays codes relating to
certain system malfunctions. Whenever power is sup-
plied to the control unit, the control unit performs a


View of the 1.8 liter engine showing the engine management components.
Ensure that all fuel connections are securely tightened.

Fuel and Engine Management 89
The procedure for fabricating an LED test lamp is
fully described in the El ectrical System section.

If a conventional test lamp with a filament type
bulb is to be used, ensure that the current draw of the
test lamp does not exceed 0.3 amp to avoid damage to
the electronic components.

To check the current draw connect an accurate
ammeter, such as the multimeter described previ-
ously, in series with the test lamp and a battery.

If the ammeter reads less than 0.3 amp the test
lamp is suitable.

Tachometer
(1) Disconnect the resistor from the tachometer
pick-up wiring connector which is located on the
ignition coil wiring harness, and connect the positive
lead of an accurate tachometer to the brown wire
terminal in the wiring connector. (2) Connect the negative lead to a good earthing
point.

View showing the location of the tachometer pickup
wiring connector with the resistor installed.
Timing Light
(1) Connect the timing light to the engine fol-
lowing the instrument manufacturers instructions.

NOTE: Do not connect or disconnect the
timing light with the engine running as
voltage surges could damage the alternator
or control unit. Do not allow the high
tension leads to open circuit with the engine
running as damage to the engine manage-
ment system could result.

(2) Do not connect the timing light positive lead
to the alternator output terminal. Where possible,
connect the power leads of the timing light to an
external power source to prevent possible transient
voltages damaging the alternator or control unit.

4. SYSTEM DIAGNOSIS AND ADJUSTMENTS
NOTE: Due to the use of complex electronic
components in the engine management sys-

tem, the diagnosis and testing procedures
described in this section should not be
carried out by persons lacking an under-
standing of electronics and the precautions
associated with the servicing of electronic
components. It is rec ommended that should
a fault arise in the system, the vehicle be
referred to an authorized workshop.

The control unit can be damaged by
component faults not indicated by the self
diagnosis codes and the renewal of the
control unit without lo cating the cause of
the failure will result in the failure of the
replacement unit. It is for this reason that
the practice of substituting components to
isolate faults is not recommended.

Prior to performing any of the follow-
ing operations, refer to the Service Pre-
cautions and Procedures heading.

PRELIMINARY CHECKS
Prior to performing the Self Diagnosis Test Pro-
cedures, perform the following preliminary checks and
rectify any problems as necessary.

(1) Check for an adequate supply of fuel in the
fuel tank. (2) Check the wiring connectors and earth points
of all engine management components for clean,
secure connections. To prevent damage to the control
unit, disconnect the negative battery terminal before
disconnecting any engine ma nagement wiring connec-
tors. (3) Check the condition of the battery. Refer to
the Electrical System sectio n for checking procedures.
Rectify any faults as necessary. (4) Check the air cleaner element for restriction.
(5) Check for air leaks at the throttle body, inlet
manifold and all related hoses. (6) Check the fuel pump pr essure as described
later in this section. (7) Ensure that the engine is in a satisfactory
mechanical condition and is in tune. Refer to the
Engine and Engine Tune-up sections as necessary.
SELF DIAGNOSIS

This function is very useful in locating system
faults particularly intermittent problems. However,
the self diagnosis mode does not provide comprehen-
sive testing of the engine management system, and
therefore should always be used in conjunction with
the other test procedures described later, in order to
accurately locate system faults.

To Interpret Self Diagnosis Codes
Once the self diagnosis mode is activated, various
fault codes will be displayed as a series of flashes by
the ECM warning lamp on the instrument cluster.

90 Fuel and Engine Management
To identify the code number, count the number of
times the ECM warning lamp flashes. Each fault code
comprises two groups of flashes separated by a 1.2
second pause. The first group represents tens and the
second group represents single units. For example 1
flash followed by a 1.2 second pause followed by 4
flashes would be code number 14. Similarly 4 flashes
followed by a 1.2 second pause followed by 2 flashes
would be code number 42.

The code will be displayed three times. If more
than one fault code is present, the self diagnosis
system will indicate each one in numerical order, with
a 3.2 second pause between each code, and then
repeat the sequence.

The fault codes can be identified as follows:
CODE NUMBER FAULT AREA
12 Satisfactory operation
13 Oxygen sensor open circuit
14 Coolant temperature sensor circuit (voltage low)
15 Coolant temperature sensor circuit (voltage high)
21 Throttle position sensor circuit (voltage high)
22Throttle position sensor circuit (voltage low)
23MAT sensor circuit (voltage' high) 1.8 liter engine
only
24 Vehicle speed sensor circuit
25 MAT sensor circuit

(voltage low) 1.8 liter engine
only
33 MAP sensor circuit

(voltage high)
34MAP sensor circuit (voltage low)
42 Electronic spark timing circuit
44
Oxygen sensor circuit

(lean exhaust)
45Oxygen sensor circuit (rich exhaust)
51 Mem-Cal
55 Control unit input circuits
Test Procedure
(1) Perform the following checks:

(a) Ensure that the battery voltage is above 11
volts. (b) Ensure that the throttle valve is fully closed.
(c) Place the transaxle in neutral.
(d) Ensure that the air conditioner, fan, tights
and all other accessories are switched off.
(2) Turn the ignition On and confirm that the
ECM warning lamp on the instrument cluster is
illuminated but not flashing.

If code 55 is displayed, refer to the Control Unit
heading, perform the circuit test procedure and rectify
the cause of the code before proceeding.

If the ECM warning lamp flashes codes other than
code 55, check the wiring harness between the diag-
nostic link connector terminal B and the control unit
wiring connector terminal A9 for shorts. Repair or
renew the wiring harness as necessary.

If no fault can be found, renew the control unit.
If the ECM warning lamp does not illuminate,
proceed as follows:

(a) Check the METER fuse located in the fuse
panel adjacent to the steering column and the fusible
links located in the fusible link connecting block at the
rear of the battery. Renew the fuse or fusible links as
necessary. (b) Check the wiring harness to the instrument
cluster. Repair or renew the harness. (c) Check the Check Engine lamp bulb. Renew if
necessary. (d) Check the EGI relay. Renew as necessary.
(3) Connect a jumper lead across terminals A
and B on the diagnostic link connector located under
the front passengers seat above the control unit.
(4) Note the codes indicated by the flashing
ECM warning lamp.
If code 12 is displayed, the system is operating
correctly.

If codes other than code 12 are displayed, refer to
the component or circuit test procedure under the
appropriate heading as indicated by the code number.

If more than one code is being displayed, test each
indicated fault working in the order of display of the
code numbers.

(5) After completing the self diagnosis test pro-
cedure, remove the jumper lead from the diagnostic
link connector. (6) After repairing or renewing the necessary

View showing the location of the diagnostic link
connector. Passengers seat removed for clarity.
Inset shows the diagnostic link connector terminal identification.

Fuel and Engine Management 91
components, erase the self diagnosis memory as
described under the following heading.

(7) Repeat the self diagnosis test procedure and
ensure that code 12 is displayed.

To Erase Memory
(1) With the ignition Off, remove the fusible link
that is positioned third from the front of the fusible
link connecting block located at the rear of the
battery. (2) Install the fusible link after 10 seconds.

View showing the location of the fusible links.
TO CHECK AND ADJUST IGNITION TIMING
(1) Connect a timing light to the engine as
previously described under the Service Precautions
and Procedures heading.
(2) Start the engine and allow it to reach normal
operating temperature. (3) Connect a jumper lead between terminals A
and B on the diagnostic link connector. (4) With the engine idling at the specified speed,
check the ignition timing with the timing light.
The timing mark on the crankshaft pulley should
be aligned with the pointer on the inner liming belt
cover.

(5) If necessary, loosen the distributor body
retaining nuts and turn the distributor until the timing
marks are aligned. (6) Tighten the distributor body retaining nuts
and check that the timing is correct. (7) Remove the jumper lead from the diagnostic
link connector and disconnect the timing light from
the engine.
TO ADJUST BASE IDLE SPEED

NOTE: The idle speed is controlled by the
idle air control (IAC) valve and is not

adjustable. The throttle stop screw controls
the base idle speed a nd is factory set. The
following base idle speed adjustment should
only be performed if the throttle body has
been renewed, or if comprehensive testing of
related components indicates that adjust-
ment is required.

(1) Before adjusting the base idle speed perform
the following tests;

(a) Check the spark plug gaps, the high tension
leads and the ignition timin g as described previously
in the Engine Tune-up section.
(b) Check the air inlet syst em for leaks between
the throttle body and inlet manifold and the inlet
manifold and cylinder head.
NOTE; Any vacuum leaks will make the
engine idle faster than it should.

(c) Check that all wiring connectors and vacuum
hoses are securely connected. (d) Ensure that the transaxle is in Park or
Neutral. (e) Ensure that the air cleaner element is service-
able.

(2) On 1.6 liter engines, remove the air cleaner
assembly, disconnect the vacuum hose from the
throttle body and seal the vacuum hose fitting.
(3) Ensure that the throttle valve moves freely
and returns to the fully closed position when slowly
released. (4) Connect an accurate tachometer to the en-
gine as previously descri bed under the Service Pre-
cautions and Procedures heading.
(5) Start the engine and allow the engine to
warm up and the idle rpm to stabilize. Check that all
electrical accessories and the air conditioning, if
equipped, are turned off. (6) With the engine idling in Park or Neutral,
slowly disconnect the brake servo unit vacuum supply
hose from the inlet manifold. Allow the engine to run
for one minute.
Location of the base idle adjusting screw. 1.8 liter
engine.

92 Fuel and Engine Management

Installed view of the throttle body assembly showing
the location of the base idle adjusting screw. 1.6 liter
engine.
(7) Disconnect the IAC valve wiring connector
and slowly connect the vacuum supply hose to the
inlet manifold. Allow five seconds to elapse and note
the engine speed.
(8) If the engine speed is not to Specifications,
remove the plug from the throttle body housing on 1.6
liter engines, or the cap from the base idle adjusting
screw on 1.8 liter engines, and adjust the idle screw
until the engine speed is 625 rpm. (9) Stop the engine and connect the IAC valve
wiring connector. (10) On 1.8 liter engines, install a new cap to
the
base idle adjusting screw.
On 1.6 liter engines, seal the throttle stop screw
with silicone sealant and install the air cleaner assem-
bly.

(11) Erase the memory codes as previously de-
scribed.
(12) Start the engine and increase the speed to
3 000 rpm for 10 seconds to allow the idle air control
valve to reset.
5. FUEL SUPPLY COMPONENTS

Special Equipment Required:
To Check Fuel Pressure — 0-500 kPa pressure
gauge

NOTE: Before proceeding with any of the
operations in this section, refer to the Ser-
vice Precautions and Procedures heading.

TO DEPRESSURISE FUEL SYSTEM
(1) Lift the front edge of the rear seat cushion on
each side, slide the cushion forward and remove it
from the vehicle. (2) Disconnect the fuel pump wiring harness
connector.
When depressurizing the fuel system, remove the rear
seat cushion and disconnect the fuel pump wiring
connector.
(3) Start and run the engine until it stalls.
Operate the starter motor for 10 seconds to ensure
that the pressure has dissipated.
(4) Connect the fuel pump wiring connector and
install the rear seat cushion.
NOTE: Failure to depressurize the fuel sys-
tem when instructed may result in a fuel
spray and possible fire.

TO TEST FOR EXTERNAL LEAKS
(1) Connect a jumper lead between terminals G
and H on the diagnostic link connector.
(2) Switch the ignition On.
(3) Check for leaks at all hose connections and
joints between the fuel pump and the engine. (4) Switch the ignition Off and remove the
jumper lead from the diagnostic link connector.
(5) If renewal of a component is necessary,
depressurize the fuel system as previously described. (6) Use only hoses and clamps as specified by
the manufacturer.
TO CHECK FUEL PRESSURE

(1) Depressurize the fuel system as previously
described. (2) On 1.6 liter engines, remove the air cleaner
as described in this section under the Air Cleaner
Assembly heading. (3) On 1.8 liter engines, release the hose clamp
securing the fuel supply hos e to the fuel rail and
disconnect the hose. On 1.6 liter engines, release the hose clamp
securing the fuel supply hose to the rear throttle body
hose fitting and disconnect the hose.

(4) Using a suitable gauge, tee piece, short piece
of fuel hose and clamps, install the pressure
gauge
between the fuel supply ho se and the fuel rail on 1.8

Fuel and Engine Management 93
liter engines, or the throttle body hose fitting on 1.6
liter engines.

(5) Tighten all connectors securely. Check for
external leaks as previously described. (6) Start the engine and note the pressure while
the engine is idling.
(7) Switch the engine Off and check that the
residual pressure does not decrease.
If the fuel pressure is within Specifications and
does not decrease, the fuel system is in a serviceable
condition. Depressurize the fuel system and discon-
nect the pressure gauge.

If the fuel pressure is a bove Specifications proceed
to operation (9).

If the fuel pressure is below Specifications proceed
to the following operation.

If the fuel pressure decreases, an internal leak is
indicated. Proceed to the following heading and carry
out the test procedure.


Testing the fuel system pressure using a pressure
gauge. 1.8 liter engine.
NOTE: There may be a small initial de-
crease in pressure when the engine is
switched Off This is acceptable and does not
indicate a fault in the system.

(8) If the fuel pressure is below Specifications
proceed as follows:

(a) Check the fuel lines for blockages and kinks
or a blocked fuel filter or fuel pump pickup strainer. (b) If no fault can be found in the previous
checks, on 1.8 liter engines clamp the fuel return hose
at the fuel rail. On 1.6 liter engines, clamp the hose that is
connected to the front throttle body hose fitting.

(c) Connect a jumper lead between terminals G
and H on the diagnostic link connector and switch the
ignition On.

NOTE: Do not operate the fuel pump for
longer than is necessary to obtain a pressure
reading.

If the fuel pressure is less than 270 kPa on 1.8 liter
engines or 90 kPa on 1.6 liter engines, renew the fuel
pump.

If the fuel pressure is more than previously
specified, renew the pressure regulator assembly on
1.8 liter engines or the pressure regulator diaphragm
on 1.6 liter engines.

(9) If the fuel pressure in operation (6) is above
Specifications, proceed as follows:

(a) On 1.8 liter engines, disconnect the fuel
return hose from the pressure regulator outlet.

On 1.6 liter engines, disc onnect the fuel return
hose from the front throttle body hose fitting.

(b) Connect a suitable length of fuel hose to the
pressure regulator or the front throttle body hose
filling and place the opposite end of the hose into a
petroleum resistant container. (c) Connect a jumper lead between terminals G
and H on the diagnostic link connector and switch the
ignition On. If the fuel pressure is 230-270 kPa on 1.8 liter
engines or 62-90 kPa on 1.6 liter engines, locate and
remove the restriction in the fuel return hose or pipe.

If the fuel pressure is more than previously
specified, renew the pressure regulator assembly on
1.8 liter engines or the pressure regulator diaphragm
on 1.6 liter engines.

TO TEST FOR INTERNAL FUEL LEAKAGE
Check the residual fuel pressure as previously
described.

If the pressure has decreased it is an indication of
an internal leak. With the pressure gauge still at-
tached, proceed as follows:

(1) Switch the ignition On to pressurize the fuel
system.
(2) As the pressure begins to decrease clamp the
fuel supply hose shut. If the pressure remains steady
the fuel pump may be consid ered faulty and should be
renewed as described later in this section. (3) If the pressure continues to decrease switch
the ignition On after it has been Off at least 10
seconds. As the pressure begi ns to decrease clamp the
fuel return hose shut. If the pressure remain steady on 1.8 liter engines,
renew the pressure regulator. If the pressure continues
to decrease, leaking inject ors are indicated. Remove
the injectors as described later in this section to locate
the leaking injectors.

If the pressure remains stea dy on 1.6 liter engines,
renew the pressure regulator diaphragm as described
later in this section. If the pressure continues to
decrease remove the injector and renew the O ring
seals as described later in this section. If this fails to
rectify the fault remove the injector and clean or
renew the injector as necessary.

Fuel and Engine Management 95
(3) Disconnect the vacuum hose from the pres-
sure regulator.
(4) Release the fuel hose clamps, disconnect the
hoses from the pressure regulator and remove the
pressure regulator. Installation is a reversal of the removal procedure
ensuring that the fuel hose clamps are tightened
securely.

To Remove and Install — 1.6 Liter Engine
(1) Depressurize the fuel system as previously
described. (2) Disconnect the negative battery terminal.
(3) Remove the air cleaner assembly. If neces-
sary, refer to the Air Cleane r Assembly heading in this
section. (4) Remove the screws securing the pressure
regulator cover to the throttle body assembly. When removing the final screw hold the cover
firmly as it is under spring tension.

(5) Remove the cover, spring seat, spring and
diaphragm from the thrott le body assembly. Discard
the diaphragm.


View of the pressure regulator components removed
from the throttle body assembly. 1.6 liter engine.
Installation is a reversal of the removal procedure
with attention to the following points:

(1) Install a new diaphragm ensuring that
the
diaphragm is correctly seat ed in the groove in the
throttle body assembly. (2) Apply Loctite 262 to the threads of the
retaining screws.
(3) Place the spring seat and the spring in the
cover and install the cover to the throttle body
assembly, ensuring that the cover is positioned on the
locating dowels. (4) While holding the cover in position install
the
retaining screws and tighten securely.
NOTE: When installing the pressure regu-
lator cover ensure that the diaphragm is not
disturbed, to prevent the possibility of a fuel
leak.

INJECTORS
To Test Injector Circuit and Injectors
(1) Disconnect the injector wiring connectors.
(2) Connect a test lamp between the injector
wiring connector terminals, ensuring that the test
lamp probes do not contact each other. (3) With the ignition switched On the test lamp
should not light. On 1.8 liter engines, check each of
the other connectors.
If the test lamp lights check the wiring harness for
a short to earth between the injector wiring connec-
tor(s) and the control unit wiring connector termi-
nal - D15 and D16 on 1.8 liter engines, or D16 on
1.6 liter engines.

(4) With the aid of an assistant, operate the
starter motor. The test lamp should flash. On 1.8 liter
engines, check each of the other connectors.

If the test lamp does not flash when connected to
the injector wiring connecto r(s), proceed to operation
(6).

If the test lamp lights as described, proceed as
follows.

If the test lamp lights but fails to flash, a faulty
control unit is indicated. Pr ior to renewing the control
unit, check the condition of the injectors as follows.

(5) Connect an ohmmeter between the terminals
of the injectors).

The resistance should be more than 1.2 ohms on
1.6 liter engines or more than 12 ohms on 1.8 liter
engines.

If the injector resistance is as specified, the
injector circuit can be considered serviceable.

If the injector resistance is not as specified, renew
the faulty injector(s).

(6) With the ignition switched On, probe the
injector wiring connector terminals with a test lamp to
earth.

If the test lamp lights when the probe contacts the
pink wire terminal on 1.6 liter engines, or the white
wire terminal on 1.8 liter engines, check the wiring
harness for a short to volt age between the injector
wiring connector(s) and the control unit wiring con-
nector terminal(s) D16 on 1.6 liter engines, or D15
and D16 on 1.8 liter engines.

If the test lamp does not light when the probe
contacts the blue wire termin al on 1.6 liter engines, or
the black and red wire term inal on 1.8 liter engines,
check the EGI relay and circ uit as described under the
EG! and Fuel Pump Relays heading in this section.

If the test lamp lights when the probe contacts the
blue wire terminal on 1.6 lite r engines, or the blue and
red wire terminal on 1.8 liter engines, proceed as
follows.

(7) Switch the ignition Off and connect the
injector wiring connectors). (8) Switch the ignition On and, using a test lamp
to earth, backprobe the cont rol unit wiring connector

96 Fuel and Engine Management

terminal D16 on 1.6 liter engines, or D15 and D16
on
1.8 liter engines.

The test lamp should light.
If the test lamp does not light check the wiring
harness for continuity between the injector wiring
connector(s) and the control unit wiring connector
terminals.

Repair or renew the wiring harness as necessary.
To Remove and Install Injectors and Fuel Rail — 1.8
Liter Engine.

(1) Depressurize the fuel system as previously
described.
(2) Disconnect the negative battery terminal.
(3) Thoroughly clean around the injectors and

View of the fuel rail, injectors and pressure regulator
removed from the engine.
the fuel rail to prevent foreign material entering the
engine.

(4) Suitably mark the fuel hoses, loosen the hose
clamps and disconnect the fuel hoses from the fuel
rail. (5) Disconnect the vacuum hose from the fuel
pressure regulator. (6) Loosen the hose clamp and disconnect the
engine ventilation hose from the throttle body. (7) Remove the bolts securing the fuel rail and
injectors to the inlet manifold. (8) Carefully raise the fuel rail and injectors
from the inlet manifold until the injector nozzles are
clear of the manifold. (9) Disconnect each injector wiring connector by
pushing in the wire retaining clip.
(10) Using a small screwdriver, remove the injec-
tor retaining clip and withdraw the injectors from the
fuel rail.
Installation is a reversal of the removal procedure
with attention to the following points:

(1) Check the condition of the injector O ring
seals and renew if necessary. (2) Install the injectors to the fuel rail and secure
with the retaining clips. (3) Connect the wiring connectors to each injec-
tor ensuring that the wire clip is locked in position. (4) Install the injectors to the inlet manifold,
carefully guiding the injectors into place ensuring that
the O ring seals are not damaged.
(5) Install the fuel rail retaining bolts and tighten
to the specified torque. (6) Install the fuel hoses to the fuel rail
and
tighten the hose clamps securely.
(7) Check for fuel leaks as previously described.
To Remove and Install Injector — 1.6 Liter Engine

(1) Depressurize the fuel system as previously
described. (2) Disconnect the negative battery terminal.
(3) Remove the air cleaner assembly. If neces-
sary refer to the heading Air Cleaner Assembly in this
section.
(4) Remove the injector retaining plate screw
and remove the injector retaining plate from the
throttle body assembly. (5) Insert the blade of a screwdriver from the
front of the throttle body assembly under the rim of
the injector in which the retaining plate locates.
Support the screwdriver on a suitable object to act as
a fulcrum. (6) Carefully lever the screwdriver until the
injector can be withdrawn from the throttle body
assembly.
(7) Remove and discard the upper and lower O
ring seals from the injector . If necessary remove the
lower filter screen from the injector.
NOTE: As the injector contains electrical

View of the fuel injector removed from the throttle body assembly. 1.6 liter engine.