1995 LAND ROVER DISCOVERY oil change

SFI
5
DESCRIPTION AND OPERATION REV: 09/95 Engine fuel temperature sensor (EFT Sensor)
This is another resistive sensor. Located on the fuel
rail it measures temperature of the rail rather than the
fuel. The resistance varies with changes in
temperature. The signal is used to increase the
injection pulse time when undergoing hot restarts.
When the fuel is hot, vapourisation occurs in the rail
and bubbles can occur in the injectors. Increasing the
pulse time flushes the bubbles away, and cools the
fuel rail with fuel from the tank. The fault may not be
evident to the driver, there may be a hot restart
problem. The fault is indicated by illumination of the
malfunction indicator light (MIL) on North American
specification vehicles.
Knock sensors
The knock sensor produces an output voltage in
proportion to mechanical vibration caused by the
engine. A sensor is located in each cylinder bank
between 2/4 and 3/5 cylinders. The ECM calculates if
the engine is knocking due to camshaft and
crankshaft sensor signals regarding the position of the
engine in the cycle. The ECM can also work out
exactly which cylinder is knocking and retards the
ignition on that particular cylinder until the knock
disappears. It then advances the ignition to find the
optimum ignition timing for that cylinder. The ECM can
adjust the timing of each cylinder for knock
simultaneously. It is possible that all eight cylinders
could have different advance angles at the same time.
If the camshaft sensor fails, the knock sensor will
continue to work, but as the engine may be running
one revolution out of sychronisation the ECM may
retard the wrong cylinder of the pair e.g. 1 instead of
6. If the knock sensor fails engine knock will not be
detected and corrected. The fault is indicated by
illumination of the malfunction indicator light (MIL) on
North American specification vehicles.Ignition coils
The electronic ignition system uses four double ended
coils. They are mounted on a bracket fitted to the rear
of the engine. The circuit to each coil is completed by
switching within the ECM, allowing each coil to charge
up and fire. Sparks are produced in two cylinders
simultaneously, one on compression stroke, the other
on exhaust stroke. Note that coil 1 feeds cylinders 1
and 6, coil 2 feeds cylinders 5 and 8, coil 3 feeds
cylinders 4 and 7, and coil 4 feeds cylinders 2 and 3.
Due to the ease of combustion in the cylinder on the
compression stroke, more energy is dissipated in that
cylinder. Coil failure will result in a lack of sparks and
misfire in the affected cylinders. The fault is indicated
by illumination of the malfunction indicator light (MIL)
on North American specification vehicles.
Injectors
A multiport fuel injection system (MFI) is used, one
injector per cylinder. Each injector consists of a small
solenoid which is activated by the ECM to allow a
metered amount of fuel to pass into the combustion
chamber. Due to the pressure in the fuel rail and the
shape of the injector orifice, the fuel squirts into the
cylinder in a fine spray to aid combustion. In the
unlikely event of injector failure a misfire will occur as
there will be no fuel to the affected cylinder. The fault
is indicated by illumination of the malfunction indicator
light (MIL) on North American specification vehicles.

19FUEL SYSTEM
6
DESCRIPTION AND OPERATION REV: 09/95 Idle air control (IAC)
Idle speed is controlled by a stepper motor which
consists of two coils. When energised in the correct
sequence the coils move a plunger which opens and
closes the throttle bypass controlling the quantity of
idle air. The stepper motor controls idle speed by
moving the plunger a set distance called a step. Fully
open is zero steps and fully closed 180 steps. Failure
of the stepper motor will result in low or high idle
speed, poor idle, engine stall or non start. The fault is
indicated by illumination of the malfunction indicator
light (MIL) on North American specification vehicles.Heated oxygen sensor (HO2S)
The oxygen sensors consist of a titanium metal
sensor surrounded by a gas permeable ceramic
coating. Oxygen in the exhaust gas diffuses through
the ceramic coating on the sensor, and reacts with the
titanium wire altering the resistance of the wire. From
this resistance change the ECM calculates the
amount of oxygen in the exhaust gas. The injected
fuel quantity is then adjusted to achieve the correct
air/fuel ratio, thus reducing the emissions of carbon
monoxide (CO), hydrocarbons (HC),and oxides of
nitrogen (NO
2). Two HO2 sensors are fitted, one in
each exhaust downpipe just ahead of the catalyst.
Note that if the wiring to these sensors is crossed, the
vehicle will start and idle correctly until the sensors
reach operating temperature. Then the ECM will read
the signals from them and send one bank of cylinders
very rich and the other very weak. The engine will
misfire, have a rough idle and emit black smoke, with
possible catalyst damage.
In the event of sensor failure, the system will default to
'open loop'. Operation and fuelling will be calculated
using signals from the remaining ECM inputs.
The fault is indicated by illumination of the malfunction
indicator light (MIL). ECM diagnostics also uses HO2
sensors to detect catalyst damage, misfire and fuel
system faults.
North American vehicles have two extra HO2 sensors
mounted one after each catalyst. These are used to
determine whether the catalysts are operating
efficently.
CAUTION: Although robust within the
vehicle environment, HO2 sensors are
easily damaged by dropping, excessive
heat and contamination. Care must be exercised
when working on the exhaust system not to
damage the sensor housing or tip.

Mpi
3
DESCRIPTION AND OPERATION Fuel system
ECM
The MEMS system is controlled by the ECM which is
located in the engine compartment.
The ECM is an adaptive unit and can learn the load
and wear characteristics of a particular engine.
The ECM remembers and updates two main engine
requirements when the engine is fully warm:
1.The idle stepper position required to achieve the
specified idle speed.
2.The fuelling change or offset required to achieve
a set oxygen sensor voltage.
The stepper position is used as a reference to update
the amount of stepper motor movement required to
achieve the specified idle speed under all conditions.
The fuelling offset is required to enable the system
when not in closed loop control to provide the correct
fuelling and while in closed loop control to prevent
having to apply excessive adjustments to the fuelling
which can adversely affect the emissions and
driveability.
NOTE: After fitting a different ECM, a full
tune procedure must be carried out using
Testbook.
The ECM inputs and outputs are shown in the table.INPUTS TO MEMS ECM
Crankshaft sensor
Manifold absolute pressure
Coolant temperature sensor
Inlet air temperature sensor
Knock sensor
Oxygen sensor
Throttle potentiometer
Throttle closed
Battery supply
Ignition supply
Diagnostic input
Power earth
Sensor earth
Fuel temperature sensor
Oxygen sensor
Air conditioning switch
OUTPUTS FROM MEMS ECM
Ignition coil
Injectors
Aircon relays
Stepper motor
Temperature gauge
Fuel pump relay (inside relay module)
Main relay (inside relay module)
Diagnostic output

19FUEL SYSTEM
4
DESCRIPTION AND OPERATION
Injectors
The four fuel injectors are fitted between the
pressurised fuel rail and inlet manifold. Each injector
comprises of a solenoid operated needle valve and a
specially designed nozzle to ensure good fuel
atomisation.
Engine coolant temperature sensor
The coolant temperature sensor is mounted in the
thermostat housing and is immersed in the engine
coolant. The sensor is a resistive device in which the
resistance varies with temperature
Throttle housing
The throttle housing is attached to the inlet manifold
via a rubber sandwich plate and incorporates a throttle
disc which is connected to the throttle pedal via the
throttle lever and a cable.
There are two breather pipes; one either side of the
throttle disc. When the engine is running with the
throttle disc open, both pipes are subject to manifold
depression and draw crankcase fumes into the
manifold. When the throttle disc is closed, only the
pipe on the inlet manifold side of the disc is subject to
manifold depression. This pipe incorporates a
restrictor to prevent engine oil being drawn into the
engine by the substantially greater manifold
depression.
Also incorporated in the throttle housing are the
throttle potentiometer and stepper motor.
Throttle potentiometer
The throttle potentiometer is mounted in front of the
throttle housing and is directly coupled to the throttle
disc shaft.
Three wires connect the throttle potentiometer to the
ECM; a 5 volt supply to the potentiometer, an earth
return to the ECM and an output voltage to the ECM
which indicates the rate of throttle disc movement.
Stepper motor
The stepper motor is contained within the throttle
housing and operates a cam and push rod via a
reduction gear. The push rod is in direct contact with
the throttle lever and moves the throttle disc to control
idle and fast idle speed. The stepper motor maximum
movement is 3.75 revolutions accomplished in steps
of 7.5°. The reduction gear converts this into 180°of
cam movement.
The throttle lever has a throttle position setting screw
which rests on the stepper motor operating pin when
the throttle pedal is released and is used to set the
relationship between engine speed and stepper motor
position.
In the side of the throttle housing is a throttle air
bypass bleed screw to provide easier and more
sensitive setting of the stepper motor position at idle.
The stepper motor position is checked using Testbook
and should be within the range of 20 to 40 steps when
the engine is run in. If it is identified as being outside
this range it can be adjusted to within range by turning
the throttle air bypass bleed screw. It is important to
follow Testbook setting procedure when adjusting this
screw to prevent mismatching of throttle body
settings. This ensures that the stepper motor is at the
optimum position within its range for providing further
movement to compensate for changes in engine load
or temperature in accordance with signals from the
ECM
NOTE: The stepper motor and throttle
position setting screws must only be
adjusted when Testbook identifies the
requirement.

33CLUTCH
2
FAULT DIAGNOSIS FAULT/SYMPTOM CHART
Symptoms
Slip Spin/Drag Judder/Fierce Fault Item
* * * Worn or oil on clutch linings 2
* * * Mechanical damage45678
* * Distorted clutch plate 2
* Failed or air in hydraulic system 12 13
* * Primary shaft tight fit in crankshaft bush 15 17
* Clutch splines sticking 2 15
* Weak clutch plate springs or insecure/worn
engine/gearbox mountings6
* Insecure/worn propeller shafts
* Insecure/worn suspension components/rubber
bushes
For items refered to in this chart.See Description and operation, Description
CLUTCH NOISE - MECHANICAL FAULTS
Noise from clutch or gearbox in neutral, which
disappears when clutch is depressed.
Suspect gearbox input/primary shaft bearings.
See MANUAL GEARBOX, Fault diagnosis,
Manual Gearbox
- Noise from gearbox in neutral, which
disappears when clutch is depressed
Noise from clutch or gearbox in neutral, which
changes tone or becomes worse when the clutch
is depressed.
Suspect worn release bearing.
Knocking/rattling from clutch or gearbox in
neutral, which is reduced or disappears when the
clutch is depressed.
Suspect worn/weak release lever retainer or
clutch unit.
Noise from clutch or gearbox in neutral, which
disappears when clutch is depressed.
Suspect gearbox fault.
See MANUAL GEARBOX, Fault diagnosis,
Manual Gearbox
- Noise from gearbox in neutral, which
disappears when clutch is depressed.HYDRAULIC FAULTS
Unable to dis-engage clutch, little or no pedal
resistance.
1.Check condition, specification and level of fluid.
2.Check pipes and cylinders for leaks.
3.Check that air vent in reservoir lid is clear.
Suspect faulty master cylinder if no fluid leaks
present.
See Repair, Master Cylinder
Spongy pedal operation
1.Check condition, specification and level of fluid.
2.Check that air vent in reservoir lid is clear.
Suspect air in fluid.
See Repair, Bleed Hydraulic System
Clutch is difficult to dis-engage and/or does not
immediately re-engage when pedal is released.
1.Check condition, specification and level of fluid.
2.Check that air vent in reservoir lid is clear.
Suspect pedal pivot, master cylinder or slave
cylinder seizure.
See Repair, Master Cylinder

R380
1
DESCRIPTION AND OPERATION MANUAL TRANSMISSION
Description
The all synchromesh five speed manual gearbox unit,
is married to a LT230T two speed transfer gearbox.
All the gears including reverse run on needle roller
bearings and the main, layshaft and primary shafts
are supported by tapered roller bearings.The whole of the geartrain is lubricated through
drillings in the shafts, supplied by a low pressure
pump driven from the rear of the layshaft. The gear
change has a single rail selector and spool type
interlock. The main and transfer gearboxes ventilate
through nylon pipes, which terminate high up in the
engine compartment to prevent water entry when the
vehicle is operating in adverse conditions.
1. Mainshaft 1st gear
2. Mainshaft 2nd gear
3. Mainshaft 3rd gear
4. Primary input shaft
5. Mainshaft 5th gear
6. Layshaft
7. Mainshaft
8. Lubrication pump9. Drain plug
10. Ventilation pipe
11. Single rail gear shift
12. 1st/2nd synchromesh
13. Oil seals
14. 3rd/4th synchromesh
15. 5th gear synchromesh

TRANSFER GEARBOX
1
SPECIFICATIONS, TORQUE TORQUE VALUES
NOTE: Torque wrenches should be regularly checked for accuracy to ensure that all fixings are
tightened to the correct torque.
Nm
LT230T Transfer gearbox
Pinch bolt - operating arm to crank arm 9......................................................
End cover gear change housing 9.................................................................
Bottom cover to transfer case 25....................................................................
Front output housing to transfer case 25........................................................
Cross shaft housing to front output housing 25...............................................
Gear change housing 25.................................................................................
Pivot shaft to link arm 25.................................................................................
Connecting rod to adjustable clevis 25...........................................................
Anti-rotation plate intermediate shaft 25.........................................................
Front output housing cover 25........................................................................
Pivot bracket to extension housing 25............................................................
Finger housing to front output housing 25......................................................
Bearing housing to transfer case 25...............................................................
Brake drum to coupling flange 25...................................................................
Bearing housing cover to transfer gearbox 45................................................
Rear output speedometer housing to transfer gearbox 45..............................
Selector finger to cross shaft high/low 25.......................................................
Selector fork, high/low to shaft 25...................................................................
Transmission brake to speedometer housing 72............................................
Gate plate to grommet plate 9.......................................................................
Gearbox to transfer case 45...........................................................................
Oil drain plug 30..............................................................................................
Oil filler/level plug 30.......................................................................................
Differential case (front to rear) 60...................................................................
Output flanges 162...........................................................................................
Differential case rear stake nut 72..................................................................
Transfer breather 15.......................................................................................
Transfer box front drive flange to drive shaft 45..............................................
Transfer box rear drive flange to drive shaft 45..............................................
Transfer gearbox mounting brackets to chassis 30........................................
Mounting brackets to transfer gearbox 55......................................................
Mounting rubbers to mounting brackets 21.....................................................
Shiftlock
Shiftlock screws 9..........................................................................................
Neutral switch 25............................................................................................

REAR AXLE AND FINAL DRIVE
1
OVERHAUL AXLE DIFFERENTIAL ASSEMBLY
Service repair no - 51.15.07.
DISMANTLE
NOTE: Mark differential components so
their original positions relative to other
components is maintained. Bearing caps
must not be interchanged.
1.Remove axle shafts then differential assembly
fom axle.
2.Remove roll pin securing bearing nut locking
fingers to bearing caps. Remove locking fingers.
3.Loosen bearing cap bolts and mark caps for
assembly.
4.Using service tool LRT-54-508, remove bearing
adjusting nuts.
5.Remove bearing cap bolts and bearing caps.
6.Remove crown wheel differential unit and
bearings.
Remove pinion FRONT AXLE DIFFERENTIAL
ONLY
7.Remove pinion flange nut using service tool
LRT-51-003 to restrain flange.
8.Remove washer and pinion drive flange.
9.Remove pinion complete with bearing and outer
bearing shims.
10.Remove pinion flange oil seal, spacer and
bearing.
Remove pinion REAR AXLE DIFFERENTIAL ONLY
7.Remove pinion flange centralizing peg using
service tool LRT-51-008.
8.Remove pinion flange nut using service tool
LRT-51-003 to restrain flange.
9.Remove pinion complete with bearing and outer
bearing shims.
10.Remove pinion flange oil seal and bearing.
11.Using service tool LRT-54-505, remove pinion
head bearing track and shim and drive out outer
bearing of differential housing.