1999 LAND ROVER DISCOVERY warning

ENGINE - V8
REPAIRS 12-2-23
Mounting - front - RH
$% 12.45.03
Remove
1.Release turnbuckles and remove battery cover.
2.Disconnect battery earth lead.
3.Raise front of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
4.Remove underbelly panel.

+ EXTERIOR FITTINGS, REPAIRS,
Panel - underbelly.
5.Position a jack beneath the sump, and support
the engine on the jack.
CAUTION: To prevent damage to
components, cushion the jack pad with a
block of wood or hard rubber.
6.Remove 2 nuts securing engine mountings to
chassis.
7.Remove nut securing RH mounting to cylinder
block.
8.Raise engine sufficiently to allow engine
mounting to be removed. Take care not to trap
any cables, pipes or harness.
9.Remove engine mounting.
10.Collect heat shield. Refit
1.Position heat shield.
2.Fit engine mounting ensuring dowel is located.
3.Lower the jack and engage engine mounting
studs in chassis.
4.Fit engine mounting nuts and tighten to 85 Nm
(63 lbf.ft).
5.Fit underbelly panel.

+ EXTERIOR FITTINGS, REPAIRS,
Panel - underbelly.
6.Remove stand(s) and lower vehicle.
7.Connect battery earth lead.
8.Fit battery cover and secure turnbuckles.

ENGINE - V8
12-2-34 REPAIRS
Ring gear - starter
$% 12.53.19
Remove
1.Remove flywheel.

+ ENGINE - V8, REPAIRS, Flywheel.
2.Drill a 3 mm (0.12 in) diameter hole at root of 2
teeth.
3.Apply a cold chisel in root of one of ring gear
teeth, strike chisel with hammer to break ring
gear.
WARNING: SUITABLE EYE PROTECTION
MUST BE WORN.
4.Remove starter ring gear. Refit
1.Clean flywheel and starter ring gear.
2.Heat new starter ring gear evenly to 350°C
(660°F), indicated when the ring is a light blue
colour.
3.Locate ring gear on flywheel and press ring
gear hard against flange on flywheel.
4.Ensure ring gear is correctly seated around the
complete circumference of flywheel and allow
to cool.
5.Fit flywheel.

+ ENGINE - V8, REPAIRS, Flywheel.

ENGINE - V8
REPAIRS 12-2-39
Switch - oil pressure
$% 12.60.50
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Raise front of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
4.Remove fixings and remove underbelly panel.
5.Disconnect multiplug from oil pressure switch.
6.Position container below switch to catch oil
spillage.
7.Remove oil pressure switch and discard
sealing washer.
Refit
1.Clean oil pressure switch threads.
2.Fit new sealing washer to switch.
3.Fit oil pressure switch and tighten to 15 Nm (11
lbf.ft) .
4.Connect multiplug to oil pressure switch.
5.Fit underbelly panel and secure with fixings.
6.Remove stand(s) and lower vehicle.
7.Connect battery earth lead.
8.Fit battery cover and retain with fixings.
9.Top up engine oil.
Cooler - engine oil
$% 12.60.68
Remove
1.Release fixings and remove battery cover.
2.Release fixings and remove cooling fan cowl.
3.Remove front grille.

+ EXTERIOR FITTINGS, REPAIRS,
Grille - front - up to 03MY.
4.Remove 6 scrivets and remove LH and RH air
deflectors from front panel.
5.Remove nut and move LH horn aside.

ENGINE - V8
12-2-66 OVERHAUL
26.Remove worn valve seat.
CAUTION: Take care not to damage the
counterbore in the cylinder head when
removing valve seats.
27.Heat cylinder head evenly to approximately
120° C (250°F).
WARNING: Handle the hot cylinder head
with care.
28.Using a suitable mandrel, press new insert fully
into counterbore.
29.Allow cylinder head to air cool.
CAUTION: Renew worn valve guides and/or
valve seats before lapping the valves.
30.Recut valve seat in head and lap in valves
using fine paste.
31.Coat valve with a small quantity of engineer's
blue, insert valve and press into position
several times without rotating. Seating position
should be in centre of valve face. 32.Check valve installed height if valve seats have
been refaced or renewed.
lValve installed height, end of valve to base
of spring seat, 'A' = 44.16 to 45.29 mm (1.74
to 1.80 in).
33.Reface valves as necessary. If a valve has to
be ground to a knife-edge to obtain a true seat,
renew valve.
34.Cut valve seats using suitable cutters:
lValve seat angle 'A' = 45°.
lValve seat insert diameter 'B' Inlet = 36.83
mm (1.45 in).
lValve seat insert diameter 'B' Exhaust =
31.50 mm (1.24 in).
lSeating width 'C' - Inlet = 0.89 to 1.4 mm
(0.035 to 0.055 in).
lSeating width 'C' - Exhaust = 1.32 to 1.83
mm (0.052 to 0.072 in).
lAngle 'D' = 70° .
lAngle 'E' = 46° to 46° 25'.
lAngle 'F' = 20° .

EMISSION CONTROL - V8
DESCRIPTION AND OPERATION 17-2-5
Evaporative emission system control
diagram
1Battery
2Fuse 13 (engine compartment fusebox)
3Inertia switch
4Main relay (engine compartment fusebox)
5Engine Control Module (ECM)
6Purge Valve (black harness connector)
7Canister vent solenoid (CVS) valve – NAS
vehicles with vacuum type EVAP system leak
detection capability only8Leak detection pump – NAS vehicles with
positive pressure type EVAP system leak
detection capability only
9Fuel tank pressure sensor – NAS vehicles with
vacuum type EVAP system leak detection
capability only
10Instrument pack (MIL warning light)
M17 0210
12
3
4
5
6
7
9
8
10

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
DESCRIPTION AND OPERATION 17-2-13
Catalytic converters for NAS low emission vehicles (LEVs) from 2000MY have active constituents of
palladium and rhodium only. The active constituents are 14PD: 1Rh and the palladium coating is used to
oxidise the carbon monoxide and hydrocarbons in the exhaust gas.
The metallic coating of platinum and palladium oxidize the carbon monoxide and hydrocarbons and convert them into
water (H
2O) and carbon dioxide (CO2). The coating of rhodium removes the oxygen from nitrogen oxide (NOx) and
converts it into nitrogen (N
2).
CAUTION: Catalytic converters contain ceramic material, which is very fragile. Avoid heavy impacts on the
converter casing.
Downstream of the catalytic converters, the exhaust front pipes merge into a single pipe terminating at a flange joint
which connects to the exhaust intermediate pipe.
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: Serious damage to the catalytic converter will occur if leaded fuel is used. The fuel tank filler neck
is designed to accommodate only unleaded fuel pump nozzles.
CAUTION: Serious damage to the engine may occur if a lower octane number fuel than recommended is used.
Serious damage to the catalytic converter will occur if leaded fuel is used.
Heated Oxygen Sensor (HO2S)
1Connection cable
2Disc spring
3Ceramic support tube
4Protective sleeve
5Clamp connection for heating element
6Heating element
7Contact element8Sensor housing
9Active sensor ceramic
10Protective tube
11Post-catalytic converter sensor
NAS spec. only)
12Pre-catalytic converter sensor
The heated oxygen sensor is an integral part of the exhaust emission control system and is used in conjunction with
the catalytic converters and the engine management control unit to ensure that the air:fuel mixture ratio stays around
the stoichiometric point of λ = 1, where the catalytic converters are most effective. Combinations of four (NAS only)
or two heated lambda sensors are used in the exhaust system dependent on market legislation.

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