LAND ROVER DISCOVERY 1995 Workshop Manual

19FUEL SYSTEM
14
REPAIR ENGINE CONTROL MODULE (ECM)
Service repair no - 18.30.03
NOTE: The ECM is not a serviceable item,
in the event of failure it must be renewed.
Remove
1.Disconnect battery negative lead.
2.Remove 'A' post trim pad.
3.Loosen multi-plug screw to ECM.
4.Disconnect multi-plug from ECM.
5.Secure multi-plug and harness aside.
6.Remove retaining nuts from ECM.
7.Manoeuvre ECM from its mounted position.
Refit
8.Refitting is the reverse of removal procedure.
9.Reconnect harness plug. Ensure plug is pushed
firmly into location and retaining clip secures
plug in position.
10.Tighten screw securing multi-plug.AIRFLOW METER
Service repair no - 18.30.15
NOTE: The air flow meter is not a
serviceable item, in the event of failure it
must be renewed.
Remove
1.Disconnect battery negative lead.
2.Release vacuum tube from EGR vacuum
capsule.
3.Disconnect airflow meter multi-plug.
4.Loosen air cleaner hose to air flow meter
retaining clip.
5.Disconnect hose from airflow meter.
6.Loosen turbo charger hose to airflow meter
retaining clip.
7.Disconnect hose from airflow meter.
8.Remove meter to mounting bracket bolts.
9.Remove airflow meter.
Refit
10.Reverse removal procedure. Ensure multi-plug is
firmly reconnected and hose clamps are
securely tightened to prevent unmetered air
entering the engine.

Tdi
15
REPAIR BOOST PRESSURE SENSOR
Service repair no - 18.30.63
Remove
1.Disconnect battery negative lead.
2.Disconnect sensor multi-plug.
3.Disconnect pressure tube union.
4.Retrieve and discard union copper washers.
5.Place pressure tube aside.
6.Remove sensor to mounting bracket bolts.
7.Remove sensor.
Refit
8.Renew all copper washers.
9.Reverse removal procedure.
INJECTION TIMING SENSOR
Service repair no - 18.30.64
Remove
1.Disconnect battery negative lead.
2.Disconnect sensor multi-plug.
3.Disconnect spill return pipe to injector.
4.Disconnect injector union.
5.Remove copper washers.
6.Remove injector clamp fixing.
7.Remove clamp.
8.Remove injector.
9.Remove injector copper washers.
Refit
10.Renew all copper washers.
11.Reverse removal procedure.
12.Check for leaks when running.

19FUEL SYSTEM
16
REPAIR ENGINE SPEED SENSOR
Service repair no - 18.30.65
Remove
1.Disconnect battery negative lead.
2.Disconnect sensor multi-plug.
3.Place vehicle on ramp and apply handbrake.
4.Raise ramp.
5.Remove sensor retaining nut.
6.Remove sensor from housing.
7.Clean housing mating faces.
Refit
8.Reverse removal procedure.

Tdi
17
REPAIR VEHICLE SPEED SENSOR
Service repair no - 18.30.22
Remove
NOTE: The following procedure is carried
out with the ramp still raised.
1.Disconnect battery negative lead.
2.Disconnect sensor multi-plug.
3.Remove sensor retaining screw.
4.Remove sensor retaining plate.
5.Remove sensor from transfer box.
Refit
6.Reverse removal procedure.CLUTCH PEDAL SWITCH
Service repair no - 18.30.67
Remove
1.Disconnect battery negative lead.
2.Disconnect switch wiring lucars.
3.Turn rear body of switch to release locknut
4.Remove locknut.
5.Remove switch from mounting bracket.
Refit
6.Reverse removal procedure.

19FUEL SYSTEM
18
REPAIR BRAKE PEDAL SWITCH
Service repair no - 18.30.66
Remove
1.Disconnect battery negative lead.
2.Disconnect switch wiring Lucars.
3.Loosen rear locknut.
4.Remove front locknut.
5.Remove switch from mounting bracket.
Refit
6.Reverse removal procedure.COOLANT TEMPERATURE SENSOR
Service repair no - 18.30.68
Remove
1.Disconnect battery negative lead.2.Disconnect sensor multi-plug.
3.Remove sensor.
4.Clean off water spillage from sensor area.
Refit
5.Fit a new copper washer.
6.Fit sensor and tighten securely.
7.Refill cooling system.
8.Run engine, check for water leaks around
sensor.

Tdi
19
REPAIR THROTTLE POSITION SENSOR
Service repair no - 18.30.17
NOTE: The throttle position sensor is not a
serviceable item, in the event of failure it
must be renewed.
Remove
1.Disconnect battery negative lead.
2.Disconnect multiplug from sensor.
3.Remove nut securing throttle pedal quadrant to
sensor. Remove throttle pedal quadrant.
4.Remove two screws securing sensor to pedal
box.
5.Remove sensor.
Refit
6.Reverse removal procedure.
CAUTION: DO NOT operate throttle
mechanism while sensor is loosely fitted,
damage may be caused to sensor wiper
track.ELECTRO-PNEUMATIC MODULATOR
Service repair no - 18.30.69
Remove
1.Disconnect battery negative lead.
2.Disconnect multi-plug from modulator.
3.Remove three vacuum pipes from modulator.
4.Remove nut securing modulator to inner wing.
5.Remove modulator.
Refit
6.Reverse removal procedure.

MFI
1
DESCRIPTION AND OPERATION DESCRIPTION
Hot Wire Multiport Fuel Injection
The 'Hot Wire' Multiport fuel injection system derives
its name from the mass air flow sensor which uses
one cold wire and one electrically heated wire to
measure the volume of air entering the engine.
The function of the system is to supply the exact
amount of fuel directly into the intake manifold
according to the prevailing engine operating
conditions.
To monitor these conditions, various sensors are fitted
to the engine to measure engine parameters. Data
from the sensors is received by the Engine control
module (ECM), the ECM will then determine the exact
amount of fuel required at any condition.
The ECM having received data from the sensors
produces pulses, the length of which will determine
the simultaneous open time of each bank of injectors
in turn, which will govern the amount of fuel injected.
Engine control module - ECM
The Multiport fuel injection system is controlled by the
14 CUX Engine Control Module comprising of a
microprocessor with integrated circuits and
components mounted on printed circuit boards. The
ECM is connected to the main harness by a 40 pin
plug.
Injectors
The eight fuel injectors are fitted between the
pressurized fuel rail and inlet manifold. Each injector
comprises a solenoid operated needle valve with a
movable plunger rigidly attached to the nozzle valve.
When the solenoid is energized the plunger is
attracted off its seat and allows pressurized fuel into
the intake manifold.Engine coolant temperature sensor
The engine coolant temperature sensor is located in
the front of the thermostat housing. The sensor
provides engine coolant information to the ECM. The
ECM increases the injector opening time when cold to
provide improved driveability, and reduces the
opening time as the engine reaches normal operating
temperature.
Engine fuel temperature sensor
The engine fuel temperature sensor is located in the
rail on the RH side of the ram housing. The sensor
sends fuel temperature data to the ECM, the ECM on
receiving the data will adjust the injector open time
accordingly to produce good hot starting in high
ambient temperatures.
Idle air control valve
The idle air control valve is screwed into a housing
attached to the rear of the plenum chamber, between
the plenum chamber and bulkhead. The idle air
control valve has two windings which enable the
motor to be energised in both directions thus opening
or closing the air valve as required by the ECM.
The idle air control valve will open and allow extra air
into the plenum chamber to maintain engine idle
speed when the engine is under increased (Electrical
and Mechanical) loads.
The idle air control valve will control engine idle speed
when the vehicle is stationary.
Heated oxygen sensors (0
2sensors) - Catalyst
vehicles
The two heated oxygen sensors are located forward
of the catalysts mounted in the exhaust downpipes.
The sensors monitor the oxygen content of the
exhaust gases and provide feedback information of
the air/fuel ratio to the ECM. Each sensor is heated by
an electrical element to improve its response time
when the ignition is switched on.

19FUEL SYSTEM
2
DESCRIPTION AND OPERATION Fuel pressure regulator
The fuel pressure regulator is mounted in the fuel rail
at the rear of the plenum chamber. The regulator is a
mechanical device controlled by plenum chamber
vacuum, it ensures that fuel rail pressure is
maintained at a constant pressure difference of 2.5
bar above that of the manifold.
When pressure exceeds the regulator setting excess
fuel is returned to the fuel tank.
Fuel pump
The electric fuel pump is located in the fuel tank, and
is a self priming 'wet' pump, the motor is immersed in
the fuel within the tank.
Air flow sensor
The hot-wire air flow sensor is mounted on a bracket
attached to the left hand valance, rigidly connected to
the air cleaner and by hose to the plenum chamber
inlet neck.
The air flow sensor consists of a cast alloy body
through which air flows. A proportion of this air flows
through a bypass in which two wire elements are
situated: one is a sensing wire and the other is a
compensating wire. Under the control of an electronic
module which is mounted on the air flow sensor body,
a small current is passed through the sensing wire to
produce a heating effect. The compensating wire is
also connected to the module but is not heated, but
reacts to the temperature of the air taken in, as engine
intake air passes over the wires a cooling effect takes
place.
The electronic module monitors the reaction of the
wires in proportion to the air stream and provides
output signals in proportion to the air mass flow rate
which are compatible with the requirements of the
ECM.Throttle position sensor
The throttle position sensor is mounted on the side of
the plenum chamber inlet neck and is directly coupled
to the throttle butterfly shaft.
The throttle position sensor is a resistive device
supplied with a voltage from the ECM. Movement of
the accelerator pedal causes the throttle valve to
open, thus rotating the wiper arm within the throttle
position sensor which in turn varies the resistance in
proportion to the valve position. The ECM lengthens
the injector open time when it detects a change in
output voltage (rising) from the throttle position
sensor.
In addition the ECM will weaken the mixture when it
detects the throttle position sensor output voltage is
decreasing under deceleration and will shorten the
length of time the injectors are open.
When the throttle is fully open, the ECM will detect the
corresponding throttle position sensor voltage and will
apply full load enrichment. This is a fixed percentage
and is independent of temperature. Full load
enrichment is also achieved by adjusting the length of
the injector open time.
When the throttle is closed, overrun fuel cut off or idle
speed control may be facilitated dependant on other
inputs to the ECM.
The throttle position sensor is 'self adaptive', which
means that adjustment is not possible. It also means
the throttle position sensor setting is not lost, for
example, when throttle stop wear occurs.
CAUTION: Do not attempt to adjust throttle
position sensor.

MFI
3
DESCRIPTION AND OPERATION Tune select resistor -
To suit individual market requirements a tune select
resistor is connected across pins 5 and 27 of the
ECM.
It is located adjacent to the ECM, and strapped to the
MFI cable assembly. The value of the resistor is
dependent on the market application:
Red wire, 180 ohms, Australia, Rest of world.
Green wire, 470 Ohms, UK and Europe - non catalyst.
Yellow wire 910 Ohms, Saudi non catalyst.
White wire, 3K9 Ohms, European catalyst
Condenser fans
It should be noted that under high coolant
temperatures, when the engine is switched off, the
condenser fans will be activated and will run for
approximately ten minutes.Vehicle speed sensor
The vehicle speed sensor is located on the side of the
Transfer box adjacent to the parking brake. The
sensor provides road speed data to the ECM. The
ECM in turn detects vehicle movement from the road
speed input and ensures that idle air control mode is
disengaged. Should the vehicle speed sensor fail in
service the ECM idle air control would become erratic.
The sensor also provides road speed data to the
electric speedometer and cruise control ECU.
Inertia fuel shutoff switch
The inertia fuel shutoff switch is a mechanically
operated switch, located on the bulkhead adjacent to
the washer reservoir under bonnet [hood].
The switch is normally closed and is in line with the
fuel pump. In the event of a sudden impact the switch
opens, and disconnects the electrical feed to the fuel
pump. The switch is reset by pressing down the
button.
WARNING: Check the integrity of the fuel
system before the inertia switch is reset.
Relay modules
The two multiport fuel injection relays are located in
the RH footwell area behind the 'A' post panel. The
main relay module is energized via the ECM when the
ignition is switched on and supplies current to the
multiport fuel injection system. The fuel pump relay
module is energized by the ECM which in turn
operates the fuel pump to pressurize the fuel system.

19FUEL SYSTEM
4
DESCRIPTION AND OPERATION ENGINE MOUNTED COMPONENTS
1. By-pass air valve (stepper motor).
2. Fuel pressure regulator.
3. Air flow meter.
4. Throttle potentiometer.
5. Fuel temperature sensor.
6. Coolant temperature sensor.
7. Fuel injector.