1999 LAND ROVER DISCOVERY gas type

GENERAL INFORMATION
03-3
Environmental Precautions
General
This section provides general information which can
help to reduce the environmental impacts from the
activities carried out in workshops.
Emissions to air
Many of the activities that are carried out in
workshops emit gases and fumes which contribute to
global warming, depletion of the ozone layer and/or
the formation of photochemical smog at ground
level. By considering how the workshop activities are
carried out, these gases and fumes can be
minimised, thus reducing the impact on the
environment.
Exhaust fumes
Running car engines is an essential part of workshop
activities and exhaust fumes need to be ventilated to
atmosphere. However, the amount of time engines
are running and the position of the vehicle should be
carefully considered at all times, to reduce the
release of poisonous gases and minimise the
inconvenience to people living nearby.
Solvents
Some of the cleaning agents used are solvent based
and will evaporate to atmosphere if used carelessly,
or if cans are left unsealed. All solvent containers
should be firmly closed when not needed and
solvent should be used sparingly. Suitable
alternative materials may be available to replace
some of the commonly used solvents. Similarly,
many paints are solvent based and the spray should
be minimised to reduce solvent emissions.
Refrigerant
It is illegal to release any refrigerants into the
atmosphere. Discharge and replacement of these
materials from air conditioning units should only be
carried out using the correct equipment.
Checklist
Always adhere to the following.
Engines:
ldon't leave engines running unnecessarily;
lminimise testing times and check where the
exhaust fumes are being blown.
Materials:
lkeep lids on containers of solvents;
lonly use the minimum quantity;
lconsider alternative materials;
lminimise over-spray when painting. Gases:
luse the correct equipment for collecting
refrigerants;
ldon't burn rubbish on site.
Discharges to water
Most sites will have two systems for discharging
water: storm drains and foul drains. Storm drains
should only receive clean water, foul drains will take
dirty water.
The foul drain will accept many of the normal waste
waters such as washing water, detergents and
domestic type wastes, but oil, petrol, solvent, acids,
hydraulic oil, antifreeze and other such substances
should never be poured down the drain. If in any
doubt speak to the Water Company first.
Every precaution must be taken to prevent spillage of
oil, fuel, solvents etc. reaching the drains. All
handling of such materials must take place well away
from the drains and preferably in an area with a kerb
or wall around it, to prevent discharge into the drain.
If a spillage occurs it should be soaked up
immediately. Having a spill kit available will make
this easier.
Additional precautions
Check whether the surface water drains are
connected to an oil water separator, this could
reduce the pollution if an incident was to occur. Oil
water separators do need regular maintenance to
ensure effectiveness.
Checklist
Always adhere to the following.
Disposal:
lnever pour anything down a drain without first
checking that it is environmentally safe to do so,
and that it does not contravene any local
regulations or bye-laws;
l have oil traps emptied regularly.
Spillage prevention:
lstore liquids in a walled area;
lmake sure that taps on liquid containers are
secure and cannot be accidentally turned on;
lprotect bulk storage tanks from vandalism by
locking the valves;
ltransfer liquids from one container to another in
an area away from open drains;
lensure lids are replaced securely on containers;
lhave spill kits available near to points of storage
and handling of liquids.

ENGINE - V8
12-2-6 DESCRIPTION AND OPERATION
Description
General
The V8 petrol engine is an eight cylinder, water cooled unit having two banks of four cylinders positioned at 90 degrees
to each other. The engine comprises five main castings - two cylinder heads, cylinder block, timing cover and the oil
sump, all of which are manufactured from aluminium alloy.
NAS market vehicles from 03 model year receive a 4.6 litre version of the V8 engine to replace the previous 4.0 litre
version.
Cylinder heads
The cylinder heads are fitted with replaceable valve guides and valve seat inserts with the combustion chambers
formed in the head. Each cylinder head is sealed to the cylinder block with a gasket. The exhaust manifolds are bolted
to the outside of each cylinder head whilst the inlet manifolds are located in the centre of the 'Vee' and are bolted to
the inside face of each head. Inlet and exhaust manifolds are sealed to the cylinder heads by means of gaskets.
Each cylinder has a single inlet and exhaust valve. The exhaust valves are of the 'carbon break' type, a recess on the
valve stem prevents a build-up of carbon in the valve guide by dislodging particles of carbon as the valve stem moves
up and down the guide. Inlet and exhaust valve stem oil seals are fitted at the top of each valve guide. Valve operation
is by means of rocker arms, push rods and hydraulic tappets. Each of the rocker arms is located on a rocker shaft
which is supported by means of pedestals bolted to the cylinder heads. A spring, positioned on either side of each
rocker arm, maintains the correct relative position of the arm to its valve stem. The rocker arms are operated directly
by the push rods which pass through drillings in the cylinder heads and cylinder block. The bottom end of each push
rod locates in a hydraulic tappet operated by the single, chain driven camshaft.
The rocker covers are bolted to the cylinder heads and are sealed to the heads by a rubber gasket. Stub pipes for
crankcase ventilation hose connections are fitted to each rocker cover, the pipe in the right hand cover incorporates
an oil separator. The engine oil filler cap is situated in the right hand cover.
Cylinder block and camshaft
The cylinder block is fitted with cast iron cylinder liners which are shrink fitted and locate on stops in the block. The
camshaft is positioned in the centre of the cylinder block and runs in one piece bearing shells which are line bored
after fitting. Camshaft end-float is controlled by a thrust plate bolted to the front of the cylinder block. A timing gear,
chain driven by the crankshaft timing gear is bolted to the front of the camshaft.
Crankshaft and main bearings
The crankshaft is carried in five main bearings. The upper main bearing shell locations are an integral part of the
cylinder block casting. The lower main bearing caps are bolted to the cylinder block on either side of the upper bearing
shell locations with an additional bolt being inserted into each cap from either side of the cylinder block. The rear
main bearing cap carries the crankshaft rear oil seal and is sealed to the cylinder block by means of cruciform shaped
seals in each side of the cap. Number four main bearing cap carries the stud fixing for the oil pick-up pipe. Lower
main bearing shells are plain whilst the upper shells have an oil feed hole and are grooved. Crankshaft end-float is
controlled by the thrust faces of the upper centre shell. The crankshaft timing gear is located on the front of the
crankshaft by means of a Woodruff key which is also used to drive the gear type oil pump. The flywheel/drive plate
carries the crankshaft position sensor reluctor ring and is dowel located and bolted to the flywheel.
Timing cover
The timing cover is bolted to the front of the cylinder block and is sealed to the block with a gasket. The disposable,
full flow oil filter canister is screwed on to the timing cover which also carries the oil pressure switch, oil pressure relief
valve and crankshaft front oil seal. The gear type oil pump is integral with the cover which also has an internal oilway
to direct oil from the oil cooler to the filter.
NOTE: Oil coolers are only fitted to vehicles up to VIN 756821.

EMISSION CONTROL - V8
DESCRIPTION AND OPERATION 17-2-9
Emission Control Systems
Engine design has evolved in order to minimise the emission of harmful by-products. Emission control systems are
fitted to Land Rover vehicles which are designed to maintain the emission levels within the legal limits pertaining for
the specified market.
Despite the utilisation of specialised emission control equipment, it is still necessary to ensure that the engine is
correctly maintained and is in good mechanical order so that it operates at its optimal condition. In particular, ignition
timing has an effect on the production of HC and NO
x emissions, with the harmful emissions rising as the ignition
timing is advanced.
CAUTION: In many countries it is against the law for a vehicle owner or an unauthorised dealer to modify or
tamper with emission control equipment. In some cases, the vehicle owner and/or the dealer may even be
liable for prosecution.
The engine management ECM is fundamental for controlling the emission control systems. In addition to controlling
normal operation, the system complies with On Board Diagnostic (OBD) system strategies. The system monitors and
reports on faults detected with ignition, fuelling and exhaust systems which cause an excessive increase in tailpipe
emissions. This includes component failures, engine misfire, catalyst damage, catalyst efficiency, fuel evaporative
loss and exhaust leaks.
When an emission relevant fault is determined, the fault condition is stored in the ECM memory. For NAS vehicles,
the MIL warning light on the instrument pack will be illuminated when the fault is confirmed. Confirmation of a fault
condition occurs if the fault is still found to be present during the driving cycle subsequent to the one when the fault
was first detected.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.
The following types of supplementary control system are used to reduce harmful emissions released into the
atmosphere from the vehicle:
1Crankcase emission control – also known as blow-by gas emissions from the engine crankcase.
2Exhaust emission control – to limit the undesirable by-products of combustion.
3Fuel vapour evaporative loss control – to restrict the emission of fuel through evaporation from the fuel
system.
4Fuel leak detection system (NAS only) – there are two types of system which may be used to check the
evaporative emission system for the presence of leaks from the fuel tank to purge valve.
aVacuum leak detection test – checks for leaks down to 1 mm (0.04 in.) in diameter.
bPositive pressure leak detection test – utilises a leak detection pump to check for leaks down to 0.5 mm (0.02
in.) in diameter.
5Secondary air injection system (Where fitted) – to reduce emissions experienced during cold starting.

EMISSION CONTROL - V8
17-2-14 DESCRIPTION AND OPERATION
The heated oxygen sensor is screwed into threaded mountings welded into the top of the front exhaust pipes at
suitable locations. They are used to detect the level of residual oxygen in the exhaust gas to provide an instantaneous
indication of whether combustion is complete. By positioning sensors in the stream of exhaust gases from each
separate bank of the exhaust manifold, the engine management system is better able to control the fuelling
requirements on each bank independently of the other, so allowing much closer control of the air:fuel ratio and
optimising catalytic converter efficiency.
Two pre-catalytic converter heated oxygen sensors are mounted in the front pipes for monitoring the oxygen content
of the exhaust gas. NAS models also have two additional post-catalytic converter heated oxygen sensors in the
exhaust front pipe.
CAUTION: HO2 sensors are easily damaged by dropping, over torquing, excessive heat or contamination.
Care must be taken not to damage the sensor housing or tip.
The oxygen sensors consist of a ceramic body (Galvanic cell) which is a practically pure oxygen-ion conductor made
from a mixed oxide of zirconium and yttrium. The ceramic is then coated with gas-permeable platinum, which when
heated to a sufficiently high temperature (≥ 350° C) generates a voltage which is proportional to the oxygen content
in the exhaust gas stream.
The heated oxygen sensor is protected by an outer tube with a restricted flow opening to prevent the sensor's
ceramics from being cooled by low temperature exhaust gases at start up. The post-catalytic sensors have improved
signal quality, but a slower response rate.
The pre-catalytic and post-catalytic converter sensors are not interchangeable, and although it is possible to mount
them in transposed positions, their harness connections are of different gender and colour. It is important not to
confuse the sensor signal pins; the signal pins are gold plated, whilst the heater supply pins are tinned,
mixing them up will cause contamination and adversely affect system performance.
Each of the heated oxygen sensors have a four pin connector with the following wiring details:
lSensor signal ground (grey wire – connects to engine management ECM)
lSensor signal (black wire – connects to engine management ECM)
lHeater drive (white wire – connects to engine management ECM)
lHeater supply (white wire – connects to fuse 2, underbonnet fuse box)
The ECM connector pins for exhaust emission control are listed in the following table:
ECM Connector 2 (C635) pin-out details for exhaust emission control system
The heated oxygen sensors should be treated with extreme care, since the ceramic material within them can be easily
cracked if dropped, banged or over-torqued; the sensors should be torqued to the recommended values indicated in
the repair procedures. Apply anti-seize compound to the sensor's threads when refitting.
WARNING: Some types of anti-seize compound used in service are a health hazard. Avoid skin contact.
WARNING: To prevent personal injury from a hot exhaust system, do not attempt to disconnect any
components until the exhaust system has cooled down.
CAUTION: Do not allow anti-seize compound to come into contact with tip of sensor or enter exhaust system.
NOTE: A new HO2 sensor is supplied pre-treated with anti-seize compound.
Pin Number Function Signal Type Control
2-01 Post-cat sensor heater (RH) - NAS only Output, Drive PWM, 12 - 0V
2-07 Post-cat sensor heater (LH) - NAS only Output, Drive PWM, 12 - 0V
2-08 Post-cat sensor (RH) - NAS only Ground, Signal 0V
2-09 Pre-cat sensor (LH) Ground, Signal 0V
2-10 Pre-cat sensor (RH) Ground, Signal 0V
2-11 Post-cat sensor (LH) - NAS only Ground, Signal 0V
2-13 Pre-cat sensor heater (RH) Output, Drive PWM, 12 - 0V
2-14 Post-cat sensor (RH) - NAS only Input, Signal Analogue, 0 - 1V
2-15 Pre-cat sensor (LH) Input, Signal Analogue, 0 - 1V
2-16 Pre-cat sensor (RH) Input, Signal Analogue, 0 - 1V
2-17 Post-cat sensor (LH) - NAS only Input, Signal Analogue, 0 - 1V
2-19 Pre-cat sensor heater (LH) Output, Drive PWM, 12 - 0V

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-5
Selector lever assembly
1Release button
2Mode switch
3Electrical connector
4Interlock solenoid (where fitted)
5Base6Gasket
7Securing bolt
8Lever
9Cover
10Position indicators
The selector lever assembly consists of a lever and a cover attached to a base. The base is located on a gasket and
secured to the transmission tunnel. The lever is hinged to the base. A latch in the lever engages with detents in the
base to provide the lever positions P, R, N, D, 3, 2, 1. The latch is disengaged by pressing a release button on the
lever knob. Except for lever movement between positions D and 3, the button must be pressed before the lever can
be moved. In some markets, vehicles incorporate an interlock solenoid at the bottom of the lever, which prevents the
lever being moved from P unless the ignition switch is in position II and the foot brake is applied. If the battery
becomes flat, the interlock system will prevent selector lever movement and removal of the ignition key.
The cover incorporates lever position indicators and the mode switch. The lever position indicators illuminate to show
the position of the selector lever. Illumination is controlled by the Body Control Unit (BCU). The mode switch is a non-
latching hinged switch that, when pressed, connects an earth to the EAT ECU to request a change of mode.
An electrical connector at the rear of the cover connects the selector lever assembly to the vehicle wiring.
Selector cable
The selector cable is a Bowden type cable that connects the selector lever assembly to a selector lever on the
gearbox. 'C' clips secure the ends of the outer cable to brackets on the selector lever assembly and the selector lever.
The inner cable is adjustable at the connection of the inner cable with the gearbox selector lever.

PANEL REPAIRS
PROCEDURES 77-2-13
PROCEDURES
General welding precautions
General
For ease of reference, the diagrams on the following pages show only the type of weld used in repair where it varies
from that used in production.
The replacement welds in the welding diagrams are denoted by the following symbols:
a = Single/Multiple thickness plug welds
b = MIG seam weld
When NOT carrying out welding operations the following criteria must be observed:
lWhere resistance spot welds have been used in production, these must be reproduced with new spot welds in
replacement where possible. All such reproduction spot welds must be spaced 30 mm (1.181 in) apart;
lWhen spot welding, it is recommended that test coupons of the same metal gauges and materials are produced
to carry out peel tests to ensure that welding equipment being used can produce a satisfactory joint. Plug welds
must be used if a satisfactory spot weld cannot be produced;
lThe electrode arms on hand-held spot welding guns must not exceed 300 mm (11.811 in) in length;
lSingle-side spot welding is not acceptable;
lBrazing and gas welding are not acceptable EXCEPT where they have been specified in production;
lWhere 3 metal thicknesses or more are to be welded together it is imperative to use MIG plug welds to ensure
joint strength;
lMIG plug welds must be used in repair joints where there is no access for a resistance spot welder. To replace
each production spot weld a hole must be drilled and/or punched, and a MIG plug weld then made in its place.
The number of plug welds must match exactly the number of spot welds which have been removed;
lWhere holes are left in an existing panel after removal of the spot welds, a single MIG plug weld will be made in
each hole as appropriate.
Seat belt anchorages
Seat belt anchorages are safety critical. When making repairs in these areas, it is essential to follow design
specifications. Note that High Strength Low Alloy (HSLA) steel may be used for seat belt anchorages.
Where possible, the original production assembly should be used, complete with its seat belt anchorages, or the cut
line should be so arranged that the original seat belt anchorage is not disturbed.
All welds within 250 mm (9.842 in) of seat belt anchorages must be carefully checked for weld quality, including
spacing of spot welds.