engine oil LAND ROVER DISCOVERY 2002 Workshop Manual

EMISSION CONTROL - V8
DESCRIPTION AND OPERATION 17-2-33
Crankcase emission control operation
Oil laden noxious gas in the engine crankcase is drawn through a spiral oil separator located in the stub pipe to the
ventilation hose on the right hand cylinder head rocker cover, where oil is separated and returned to the cylinder head.
The rubber ventilation hose from the right hand rocker cover is routed to a port on the right hand side of the inlet
manifold plenum chamber, where the returned gases mix with the fresh inlet air passing through the throttle butterfly
valve. The stub pipe on the left hand rocker cover does not contain an oil separator, and the ventilation hose is routed
to the throttle body housing at the air inlet side of the butterfly valve. The mass of fresh air which is drawn in from the
atmospheric side of the throttle butterfly to mix with the returned crankcase gas depends on the throttle position and
the engine speed.
1Hose – RH rocker cover to inlet manifold
2Inlet manifold
3Throttle body
4Air intake
5Hose – LH rocker cover to inlet manifold
6LH rocker cover breather tube (without oil
separator)7LH rocker cover baffle
8RH rocker cover baffle
9RH rocker cover breather tube
10Oil separator (integral with breather tube)
When the engine is running in cruise conditions or at idle, manifold pressure is low and the majority of gases are drawn
into the inlet manifold through the oil / vapour separator in the RH rocker cover stub pipe. At the same time, filtered
air is drawn from the throttle body into the engine via the LH rocker cover.
During periods of driving at Wide Open Throttle (WOT), pressure at either side of the throttle disc equalizes (manifold
depression collapses). The larger ventilation opening at the throttle housing positioned in the fast moving stream of
intake air, now offers more 'pull' than the small opening in the RH rocker cover and the flow of ventilation reverses,
drawing gases from the LH rocker cover into the throttle body for subsequent burning in the combustion chambers.

EMISSION CONTROL - V8
17-2-42 DESCRIPTION AND OPERATION
Secondary air injection system
When the engine is started, the engine control module checks the engine coolant temperature and if it is below 55°
C, the ECM grounds the electrical connection to the coil of the secondary air injection (SAI) pump relay.
A 12V battery supply is fed to the inertia switch via fuse 13 in the engine compartment fusebox. When the inertia
switch contacts are closed, the feed passes through the switch and is connected to the coil of the Main relay. An earth
connection from the Main relay coil is connected to the ECM. When the ECM completes the earth path, the coil
energises and closes the contacts of the Main relay.
The Main and Secondary Air Injection (SAI) pump relays are located in the engine compartment fusebox. When the
contacts of the Main relay are closed, a 12V battery supply is fed to the coil of the SAI pump relay. An earth connection
from the coil of the SAI pump relay is connected to the ECM. When the ECM completes the earth path, the coil
energises and closes the contacts of the SAI pump relay to supply 12V to the SAI pump via fusible link 2 in the engine
compartment fusebox. The SAI pump starts to operate, and will continue to do so until the ECM switches off the earth
connection to the coil of the SAI pump relay.
The SAI pump remains operational for a period determined by the ECM and depends on the starting temperature of
the engine, or for a maximum operation period determined by the ECM if the target engine coolant temperature has
not been reached in the usual time.
When the contacts of the main relay are closed, a 12V battery supply is fed to the SAI solenoid valve via Fuse 2 in
the engine compartment fusebox.
The ECM grounds the electrical connection to the SAI vacuum solenoid valve at the same time as it switches on the
SAI pump motor. When the SAI vacuum solenoid valve is energised, a vacuum is provided to the operation control
ports on both of the vacuum operated SAI control valves at the exhaust manifolds. The control vacuum is sourced
from the intake manifold depression and routed to the SAI control valves via a vacuum reservoir and the SAI vacuum
solenoid valve.
The vacuum reservoir is included in the vacuum supply circuit to prevent vacuum fluctuations caused by changes in
the intake manifold depression affecting the operation of the SAI control valves.
When a vacuum is applied to the control ports of the SAI control valves, the valves open to allow pressurised air from
the SAI pump to pass through to the exhaust ports in the cylinder heads for combustion.
When the ECM has determined that the SAI pump has operated for the desired duration, it switches off the earth paths
to the SAI pump relay and the SAI vacuum solenoid valve. With the SAI vacuum solenoid valve de-energised, the
valve closes, cutting off the vacuum supply to the SAI control valves. The SAI control valves close immediately and
completely to prevent any further pressurised air from the SAI pump entering the exhaust manifolds.
The engine coolant temperature sensor incurs a time lag in respect of detecting a change in temperature and the SAI
pump automatically enters a 'soak period' between operations to prevent the SAI pump overheating. The ECM also
compares the switch off and start up temperatures, to determine whether it is necessary to operate the SAI pump.
This prevents the pump running repeatedly and overheating on repeat starts.
Other factors which may prevent or stop SAI pump operation include the prevailing engine speed / load conditions.

ENGINE MANAGEMENT SYSTEM - TD5
DESCRIPTION AND OPERATION 18-1-31
The purpose of the glow plugs is:
lAssist cold engine start.
lReduce exhaust emissions at low engine load/speed.
The main part of the glow plug is a tubular heating element that protrudes into the combustion chamber of the engine.
The heating element contains a spiral filament that is encased in magnesium oxide powder. At the tip of the tubular
heating element is the heater coil. Behind the heater coil and connected in series is a control coil. The control coil
regulates the heater coil to ensure that it does not overheat and cause a possible failure. The glow plug circuit has its
own control relay located in the engine compartment fuse box.
Pre-heat is the length of time the glow plugs operate prior to engine cranking. The ECM controls the pre-heat time of
the glow plugs based on battery voltage and coolant temperature information via the glow plug relay.
Post-heat is the length of time the glow plugs operate after the engine starts. The ECM controls the post-heat time
based on ECT information. If the ECT fails the ECM will operate pre/post-heat time strategies with default values from
its memory. The engine will be difficult to start.
Input/Output
The glow plugs receive voltage from the glow plug relay that is controlled by the ECM. The ECM provides the earth
path for the relay coil closing the relay contacts and supplying the glow plugs with battery voltage. The supply voltage
heats the coils to approximately 1000
°C (1832 °F). The glow plug circuit is wired in parallel, the body of each glow
plug is screwed directly into the engine block which provides each glow plug with an earth path.
The glow plugs can fail in the following ways:
lHeater coil open circuit.
lControl coil open circuit.
lPoor earth quality.
lShort circuit to vehicle supply.
lShort circuit to vehicle earth.
lWiring loom fault.
lRelay windings open circuit.
lIncorrect relay fitted.
In the event of a glow plug failure any of the following symptoms may be observed:
lDifficult starting.
lExcessive smoke emissions after engine start.

ENGINE MANAGEMENT SYSTEM - TD5
DESCRIPTION AND OPERATION 18-1-33
The turbocharger is exposed to extremely high operating temperatures (up to 1,000 °C (1832 °F)) because of the hot
exhaust gases and the high speed revolution of the turbine (up to 150,000 rev/min). In order to resist wear of the
turbine bearings a flow of lubrication oil is supplied from the engine lubrication system to keep the bearings cool. Oil
is supplied from a tapping at the front of the full-flow filter adaptor housing via a metal pipe with banjo connections.
Oil is returned to the sump via a metal pipe which connects to the cylinder block at a port below the turbocharger
assembly.
A heatshield is attached to the left hand side of the engine to protect adjacent components from the heat generated
at the turbocharger. The heatshield is attached to the engine by two bolts an additional bolt attaches the heatshield
to the turbocharger casting.
The engine control module controls the amount of boost pressure the engine receives by way of the turbocharger.
When full boost is reached a control signal is sent to the wastegate modulator, and a vacuum is applied to the
wastegate valve. The wastegate valve opens, bypassing some of the exhaust gas away from the turbine to be output
to the exhaust system.
The engine should be allowed to idle for 15 seconds following engine start up and before the engine is switched off
to protect the turbocharger by maintaining oil supply to the turbine bearings.
Intercooler
The intercooler is an air-to-air heat exchanger which lowers the intake air temperature to obtain a higher air density
for better combustion efficiency. The intercooler receives compressed air from the turbocharger via a metal pipe; it
cools the intake air via the intercooler matrix and delivers it to the intake manifold by means of a rubber hose which
connects between the intercooler outlet and the intake manifold outlet. The rubber hose is connected to ports at each
end by metal band clips.

+ COOLING SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.
The intercooler is located at the front of the engine bay, forward of the radiator.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-55
Turbocharger
$% 19.42.01
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Release fixings and remove battery cover.
3.Disconnect battery earth lead.
4.Remove cooling fan cover.
5.Remove 3 bolts and remove exhaust manifold
heat shield.
6.Release clip and disconnect breather hose
from camshaft cover.
7.Release clip and disconnect vacuum hose from
turbocharger wastegate.
8.Loosen clips and release air intake and outlet
hoses from turbocharger. 9.Remove turbocharger oil feed banjo bolt and
discard sealing washers.
10.Remove 2 bolts and release turbocharger oil
drain pipe and discard gasket.
11.Remove 3 nuts and release exhaust front pipe
from turbocharger and discard gasket.
12.Remove 3 nuts securing turbocharger to
exhaust manifold.
13. Remove turbocharger and discard gasket.
Refit
1.Clean turbocharger and exhaust manifold
mating faces.
2.Using a new gasket, fit turbocharger to exhaust
manifold and tighten nuts to 30 Nm (22 lbf.ft).
3.Using new gasket, align exhaust front pipe and
tighten nuts to 30 Nm (22 lbf.ft).
4.Using new gasket, align turbocharger drain
pipe and tighten bolts to 9 Nm (7 lbf.ft).
5.Fit banjo bolt to oil feed pipe using new sealing
washers and tighten to 25 Nm (18 lbf.ft)..
6.Position air hoses to turbocharger and tighten
clips.
7.Position and secure breather hose to camshaft
cover.
8.Position and secure vacuum hose to
turbocharger wastegate.
9.Position exhaust manifold heat shield and
tighten M6 bolts to 9 Nm (7 lbf.ft) and M8 bolt to
25 Nm (18 lbf.ft).
10.Fit fan cowl and secure fixings.
11.Fit acoustic cover and secure the fixings.
12.Connect battery earth lead.
13.Fit battery cover and secure fixings.

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-3
Engine management component
location - Engine compartment
1Mass air flow/ inlet air temperature sensor
2Fuel injectors
3High tension leads/spark plugs
4Fuel pump relay
5ATC compressor clutch relay/ cooling fan relay
6Throttle position sensor
7Heated oxygen sensor
8Idle air control valve
9Ignition coils
10Engine coolant temperature sensor
11Crankshaft speed and position sensor
12Knock sensor
13Camshaft position sensor

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-5
1Engine control module
2Crankshaft speed and position sensor
3Camshaft position sensor
4Engine coolant temperature sensor
5Mass air flow/ inlet air temperature sensor
6Throttle position sensor
7Heated oxygen sensors
8Fuel injectors
9Idle air control valve
10Fuel pump relay
11EVAP canister
12EVAP canister vent valve
13EVAP canister purge valve
14Fuel tank pressure sensor
15Ignition coils
16Knock sensor
17Spark plugs
18High/ Low ratio switch
19Malfunction indication lamp
20Diagnostic connector
21Air temperature control clutch relay
22Air temperature control cooling fan relay
23ATC ECU
24CAN link to EAT
25SLABS ECU
26BCU
27Instrument cluster
28Thermostat monitoring sensor (where fitted)

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-7
The ECM controls the following outputs:
lFuel injectors (1 per cylinder).
lIgnition coils/ high tension leads/ spark plugs.
lFuel pump relay.
lIdle air control valve.
lHeated oxygen sensors.
lEVAP canister purge valve.
lEVAP canister vent solenoid (CVS) valve (where fitted).
lMalfunction Indicator Lamp (MIL)/ service engine soon lamp (where fitted).
lHill descent control (via SLABS interface).
lEVAP system fuel leak detection pump (where fitted)
lSecondary air injection pump (where fitted)
The ECM also interfaces with the following:
lDiagnostics via diagnostic connector with TestBook.
lController Area Network (CAN) link to EAT ECU.
lAir conditioning system.
lSelf Levelling & Anti-lock Braking System (SLABS) ECU.
lImmobilisation system via the body control unit (BCU).
lInstrument cluster.
lCruise control ECU
lActive Cornering Enhancement (ACE) ECU
Engine Control Module (ECM)
The engine control module (ECM) is located on the RH side A post below the face panel inside the vehicle. It has a
cast aluminium case and is mounted on a bracket. The ECM has 5 independent connectors totalling 134 pins.
The ECM is available in 4 variants:
lNAS.
lNAS low emission vehicles.
lUK/ Europe/ Japan/ Australia.
lROW/ Gulf.
The ECM uses a 'flash' electronic erasable programmable read only memory (EEPROM). This enables the ECM to
be externally configured, to ensure that the ECM can be updated with any new information, this also allows the ECM
to be configured with market specific data. TestBook must be used to configure replacement ECM's. The ECM can
be reconfigured up to 16 times to meet changing specifications and legislation.
The ECM memorises the positions of the crankshaft and the camshaft when the engine has stopped via the CKP and
CMP sensors. This allows immediate sequential fuel injection and ignition timing during cranking. This information is
lost if battery voltage is too low (i.e. flat battery). So the facility will be disabled for the first engine start.

ENGINE MANAGEMENT SYSTEM - V8
18-2-12 DESCRIPTION AND OPERATION
Connector 5 (C0638): This connector contains 9 pins and is used to control the ignition system. The ignition coils are
supplied with power and a switching earth completes the circuit.
Pin out details connector C0638
Crankshaft speed and Position (CKP) sensor (C0168)
The CKP sensor is located towards the rear of the engine below cylinder number 7, with its tip adjacent to the outer
circumference of the flywheel. The CKP sensor is the most important sensor on the vehicle and without its signal the
engine will not run. The signal produced by the CKP sensor allows the ECM to determine crankshaft angle and speed
of rotation. The ECM uses this information to calculate ignition timing and fuel injection timing.
The CKP sensor works as a variable reluctance sensor. It uses an electromagnet and a reluctor ring to generate a
signal. As the reluctor ring passes the tip of the CKP sensor the magnetic field produced by the sensor is cut and then
re-instated. The ECM measures the signal as an ac voltage.
The output voltage varies in proportion to engine speed. The reluctor ring has a set tooth pattern, 60 teeth are spaced
at 6
° intervals and are 3° wide, two teeth are removed to provide a reference mark at 60° BTDC for number 1 cylinder.
There is no back up strategy or limp home facility if this sensor fails, the engine does not run.
Pin No. Function Signal type Reading
1 Not used - -
2 Ignition , Cylinders 2 and 3 Output Switch to earth
3 Not used - -
4 Not used - -
5 Ignition coil earth Earth 0V
6 Ignition , Cylinders 1 and 6 Output Switch to earth
7 Ignition , Cylinders 4 and 7 Output Switch to earth
8 Ignition , Cylinders 5 and 8 Output Switch to earth
9 Not used - -

ENGINE MANAGEMENT SYSTEM - V8
18-2-32 DESCRIPTION AND OPERATION
Idle Air Control Valve (IACV) (C0641)
The IACV is located on the side of the air inlet pipe on top of the engine. The IACV is used to maintain good quality
idle speed under all operating conditions.
When an engine is running at idle it is subject to a combination of internal and external loads that can affect idle speed.
These loads include engine friction, water pump, alternator operation, and air conditioning.
The IACV acts as an air bypass valve. The ECM uses the IACV to enable the closed loop idle speed calculation to be
made by the ECM. This calculation regulates the amount of air flow into the engine at idle, therefore compensating
for any internal or external loads that may affect idle speed.
The IACV utilises two coils that use opposing PWM signals to control the position of opening/closing of a rotary valve.
If one of the circuits that supply the PWM signal fails, the ECM closes down the remaining signal preventing the IACV
from working at its maximum/ minimum setting. If this should occur, the IACV automatically resumes a default idle
position. In this condition, the engine idle speed is raised and maintained at 1200 rev/min with no load placed on the
engine.
The idle speed in cold start condition is held at 1200 rev/min in neutral for 20 seconds and ignition timing is retarded
as a catalyst heating strategy. The cold start idle speed and the default idle position give the same engine speed 1200
rev/min, and although they are the same figure they must not be confused with each other as they are set separately
by the ECM.
Note that the rotary valve must not be forced to move by mechanical means. The actuator can not be
serviced; if defective, the entire IACV must be replaced.
Input/Output
The input to the IACV is a 12 volt signal from fuse 2 located in the engine compartment fuse box. The output earth
signal to open and close the actuator is controlled by the ECM as follows:
lIACV (open signal) - via pin 42 of connector C0636 of the ECM
lIACV (closed signal) - via pin 43 of connector C0636 of the ECM
The IACV can fail the following ways or supply incorrect signal:
lActuator faulty.
lRotary valve seized.
lWiring loom fault.
lConnector fault.
lIntake system air leak.
lBlocked actuator port or hoses.
lRestricted or crimped actuator port or hoses.