1996 LAND ROVER DEFENDER sensor

19FUEL SYSTEM
10
DESCRIPTION AND OPERATION Under varying engine speed and load condition the
control unit sends a signal to open the vacuum
modulator which allows a vacuum to be applied above
the EGR diaphragm. The vacuum supply is taken from
a 'T' connector in the brake servo hose. This process
is controlled by an engine speed/load map stored in
the EGR control unit memory.
Engine speed is measured by monitoring the
waveform present on one phase of the generator.
Throttle position is measured via a sensor mounted on
the fuel injection pump throttle lever. Closed loop
control is achieved by allowing the control unit (ECU)
to continually monitor EGR valve lift via the sensor
mounted on the valve; this valve lift is compared with
the actual valve lift required on the control unit map
and adjusted, if necessary.
With coolant temperature between 20°C and 100°C,
the engine having just returned to idle, EGR will shut
off after 25-30 seconds idling.

FUEL SYSTEM
1
ADJUSTMENT THROTTLE CABLE
Adjust
1.Slacken throttle cable adjustment ferrule.
2.Hold throttle lever in fully closed position.
3.Adjust outer cable, by rotating ferrule, to give
1,57 mm (1/16 in) of deflection in the inner cable.
4.Check that throttle opens fully when the throttle
is depressed.EGR THROTTLE POSITION SENSOR
Check
1.Run engine until normal operating temperature is
reached.
2.Switch off engine and disconnect throttle position
sensor multi-plug.
3.Connect an Ohmmeter across pins 1 and 3 of
multi-plug. Ohmmeter should read between 1K
and 1.05K ohms.
4.Connect Ohmmeter across pins 1 and 2 of
multi-plug. Ohmmeter should read between 850
and 900 ohms.
5.If readings are correct, reconnect multi-plug.
6.If readings are not obtained slacken 2 torx
screws securing sensor.
7.Rotate sensor to obtain correct Ohmmeter
reading, then tighten torx screws.
8.Re-check readings and fit multiplug.
9.If, after adjustment, Ohmmeter readings cannot
be achieved, fit new sensor.
See Repair, EGR
throttle position sensor

FUEL SYSTEM
1
REPAIR FUEL INJECTION PUMP
Service repair no - 19.30.07
Remove
1.Disconnect battery.
2.Disconnect and remove high pressure fuel
injection pipes, pump to injectors.
3.Viewing valve mechanism through oil filler cap
aperture, turn crankshaft clockwise until No. 1
cylinder is just before TDC.
4.Remove blanking plug from flywheel housing
and fit timing toolLRT-12-044, locating centre
pin on flywheel.
NOTE: A chassis undertray may be fitted
on some vehicle derivatives to conform to
legal requirements. When under chassis
adjustments or remove and refit procedures are
required, it may be necessary to remove the
undertray and/or integral access panels
See
CHASSIS AND BODY, Repair, Front undertray
or
See CHASSIS AND BODY, Repair, Rear undertray
5.Carefully rotate crankshaft clockwise until centre
pin engages with timing slot in flywheel.
6.Remove injection pump access plate, complete
with gasket, from front cover plate.
7.Fit pin fromLRT-12-045to injection pump gear.
8.Restrain pulley nut to prevent straining timing
belt and remove drive gear to pump hub fixing
bolts and retaining plate.
9.Remove pin from pump gear.
10.Fit gear retaining toolLRT-12-045with an 8 mm
washer, 1,5 - 2 mm thick, under each bolt head
in addition to the existing washer.
11.Remove throttle cable and hand throttle cable, if
fitted.
12.Disconnect lead from fuel cut-off solenoid, and
EGR throttle position sensor multi-plug, if fitted.

19FUEL SYSTEM
2
REPAIR
13.Remove banjo bolts securing spill return, main
fuel and boost signal pipes, refit banjo bolts after
disconnecting pipes.
14.Remove 2 bolts securing rear of pump to
mounting bracket.
15.Remove 3 pump securing nuts at flange and
withdraw pump and gasket.
16.Fit suitable caps to pipe connections to prevent
ingress of dirt.
Refit
17.Clean mating faces of pump and front cover and
fit new gasket into position over pump mounting
studs.
18.Remove pump blanking plugs.
19.Slacken the 3 bolts, securing injection pump
mounting bracket to cylinder block, sufficiently
enough to allow bracket to move.
20.Fit pump to cover and secure with 3 nuts.
Tighten to
25 Nm (18 lbf/ft).
21.Loosely attach pump to mounting bracket with
nuts and bolts, then tighten bolts securing
bracket to cylinder block and bolts securing
pump to bracket, finger tight only.
22.To ensure correct fitting and alignment of
injection pump, first tighten the 2 bolts securing
pump to mounting bracket to
25 Nm (18 lbf/ft).
Then tighten the 3 bolts securing mounting
bracket to cylinder block, also to
25 Nm (18
lbf/ft).
23.Connect spill return and main fuel pipes and
secure with banjo bolts. Tighten to
25 Nm (18
lbf/ft).
24.Connect boost signal pipe and secure with banjo
bolt. Tighten to
10 Nm (7 lbf/ft).
25.Connect fuel cut-off solenoid lead and throttle
position sensor multi-plug, if fitted.
26.Connect throttle cable and where applicable,
hand throttle cable.
27.Remove pump gear retaining toolLRT-12-045.
28.Carefully turn the pump hub nut in a clockwise
direction, sufficiently enough to enable timing
tool pin to be inserted into injection pump.
29.Fit gear retaining plate and secure with 3 bolts.
Tighten to
25 Nm (18 lbf/ft).
30.Remove timing pin.
31.Ensure flywheel timing pin is disengaged from
slot in flywheel.
32.Turn crankshaft two complete revolutions, check
timing pin fromRT-12-045can be fully and
easily inserted into the pump. At the same time
check flywheel timing pinLRT-12-044can also
be inserted in the flywheel slot.
33.If, with the flywheel timing pin located, the timing
pin cannot be inserted cleanly into the injection
pump, carry out the following:
a.Ensure flywheel timing pin is disengaged from
slot in flywheel.
b.Slacken the 3 pump gear retaining bolts.
c.Turn the pump hub nut in a clockwise
direction, sufficiently to enable timing tool pin to
be easily inserted into the injection pump.
d.Keeping the tension on the hub nut, check
that flywheel timing pin locates with slot in
flywheel.
e.Tighten the 3 pump gear retaining bolts to
25
Nm (18 lbf/ft).
f.Remove timing pins from pump and flywheel
housing.
34.Using a suitable anti-seize compound, fit the
blanking plug to flywheel housing. Tighten to
12
Nm (9 lbf/ft).
35.Fit access plate with gasket to front cover plate.
Tighten bolts to
25 Nm (18 lbf/ft).
36.Refit injector pipes.
37.Reconnect battery.

19FUEL SYSTEM
18
REPAIR EGR THROTTLE POSITION SENSOR
Service repair no - 17.45.08
Remove
1.Remove 2 screws securing throttle position
sensor mounting plate to injection pump.
2.Disconnect sensor multi-plug.
3.Remove sensor assembly.
Refit
4.Position sensor assembly on injection pump and
secure with screws.
5.Connect multi-plug.
6.Adjust sensor
See Adjustment, EGR throttle
sensor
EGR CONTROL UNIT
Service repair no - 17.45.07
Remove
1.Raise centre seat, or cubby box
See CHASSIS
AND BODY, Repair, Cubby box
to gain access
to EGR control unit harness.
2.Disconnect control unit multi-plug and remove
centre seat or cubby box.
3.Remove 4 screws and detach control unit from
seat or cubby box base.
Refit
4.Secure EGR control unit to base of centre seat
or cubby box.
5.Position centre seat or cubby box and connect
control unit multi-plug.
6.Fit centre seat, or cubby box.
See CHASSIS
AND BODY, Repair, Cubby box

82AIR CONDITIONING
2
DESCRIPTION AND OPERATION Operation
Evaporator unit and expansion valve
High pressure liquid refrigerant is delivered to the
expansion valve which is the controlling device for the
air conditioning system. A severe pressure drop
occurs across the valve and as the refrigerant flows
through the evaporator it picks up heat from the
ambient air, boils and vaporizes. As this change of
state occurs, a large amount of latent heat is
absorbed. The evaporator is therefore cooled and as
a result heat is extracted from the air flowing across
the evaporator. The refrigerant leaves the evaporator,
on its way to the compressor, as a low pressure gas.
An evaporator sensor measures the air temperature at
the evaporator and engages or disengages the
compressor clutch to prevent icing of the air ways.
Compressor
The compressor, a pump specially designed to raise
the pressure of the refrigerant, is mounted on the front
of the engine and is driven by an independent drive
belt from the crankshaft pulley. The compressor draws
vaporized refrigerant from the evaporator. It is
compressed with a resulting rise in temperature and
passed on to the condenser as a hot, high pressure
vapour.
Condenser
The condenser is mounted directly in front of the
radiator and consists of a refrigerant coil mounted in a
series of thin cooling fins to provide the maximum
heat transfer. Air flow across the condenser is induced
by vehicle movement and assisted by two electric fans
attached to the frame of the condenser. The
refrigerant high pressure vapour enters the condenser
inlet on the RH side. As the vapour passes through
the condenser coils the air flow, assisted by the two
fans, carries the latent heat away from the condenser.
This induces a change of state resulting in the
refrigerant condensing into a high pressure warm
liquid. From the condenser, the refrigerant continues
to the receiver/ drier.
Receiver/drier
This component acts as a reservoir and is used to
hold extra refrigerant until it is needed by the
evaporator. The drier within the receiver unit contains
a filter and dessicant (drying material) which absorb
moisture and prevent dessicant dust from being
carried with the refrigerant into the system.AIR CONDITIONING AND HEATER CONTROLS -
LH DRIVE
1. Temperature control
Move the lever upwards (RED) to increase air
temperature, or downwards (BLUE) to reduce air
temperature.
2. Air conditioning switch
Press the switch (indicator lamp illuminates) to
activate the air conditioning. Press again to switch off.
3. Air recirculation control
Move the lever fully upwards to activate air
recirculation. Move the lever fully downwards to
cancel recirculation.
NOTE: Prolonged recirculation may cause
the windows to mist up.
4. Air distribution control
Lever fully up - air to windscreen vents (also provides
some air to the footwell).
Lever midway - air to fascia vents (also provides some
air to the footwell).
Lever fully down - air to footwell vents (also provides
some air to the windscreen).

AIR CONDITIONING
9
REPAIR EXPANSION VALVE - LH DRIVE
Service repair no - 82.25.01
Remove
1.Remove heater/cooler unit
See Heater/cooler
unit.
2.Suitably support unit on a bench to prevent
damage to heater matrix pipes.
3.Remove 7 screws securing outlet duct to
heater/cooler unit.
4.Break sealing compound around edge of duct
and pull duct from unit.
5.Remove all fixing screws securing top cover
seam and cover sides to main casing.
6.Remove 4 screws and 4 nuts from top of cover.
7.Break sealing compound from unit casing and
top cover.
8.Lift off top cover, release grommet and feed
blower motor wiring and air flap operating rod
through respective apertures. Note thermostat
temperature probe which is inserted in top of
evaporator.
9.Release 2 clips securing expansion valve sensor
and lagging to low pressure pipe.
10.Unscrew union securing expansion valve to
evaporator high pressure pipe.
11.Remove expansion valve, complete with high
pressure pipe.
12.Disconnect high pressure pipe from expansion
valve.
13.Discard all pipe connection 'O' rings.
14.Clean sealing compound from all joints of main
casing, top cover and outlet duct.
Refit
15.Coat unions, threads and new 'O' rings with
refrigerant oil prior to reassembly.
16.Fit high pressure pipe to new expansion valve.
17.Fit expansion valve to evaporator pipe
connector.
18.Position valve sensor at low pressure pipe and
secure with lagging and clips.
19.Apply sealing compound around top edge of
main casing.
20.Feed blower motor wiring through top cover and
fit grommet.
21.Fit top cover to casing. Ensure thermostat
temperature probe is inserted in top of
evaporator. Apply mastic sealant to air flap
operating rod aperture.
22.Apply sealing compound to joint face of blower
motor outlet duct.
23.Locate duct over blower motor outlet and secure
to casing.
24.Fit heater/cooler unit
See Heater/cooler unit.

82AIR CONDITIONING
16
REPAIR EXPANSION VALVE - RH DRIVE
Service repair no - 82.25.01
Remove
1.Remove evaporator
See Evaporator - RH
drive.
2.Unscrew union securing pressure sensor to low
pressure pipe.
3.Release spring clip securing temperature sensor
to low pressure pipe.
4.Unscrew union and remove expansion valve
from evaporator high pressure pipe.
5.Remove high pressure pipe from expansion
valve.
6.Discard all pipe connection 'O' rings.
Refit
7.Coat unions, threads and new 'O' rings with
refrigerant oil prior to reassembly.
8.Fit high presssure pipe to new expansion valve.
9.Fit expansion valve to evaporator high pressure
pipe.
10.Secure temperature and pressure sensors to low
pressure pipe.
11.Fit evaporator
See Evaporator - RH drive.