coolant LAND ROVER DISCOVERY 1995 Owner's Guide

12ENGINE
16
REPAIR 14.Release clip and disconnect brake servo hose
from manifold.
15.Disconnect fuel temperature sensor multiplug.
16.Remove 3 bolts securing engine harness to
manifold.
17.Disconnect fuel injection harness multiplug.
18.Disconnect inlet manifold air temperature sensor
multiplug.
19.Release clip and disconnect fuel hose from
pressure regulator.
CAUTION: Plug the connections
20.Release clips and disconnect 3 hoses from
manifold.
21.Remove bolt securing dipstick tube to coolant
rail.

12ENGINE
18
REPAIR Refit
1.Fit location dowels to cylinder head.
2.Fit cylinder head gasket to cylinder block.
3.Using assistance fit cylinder head to cylinder
block.
4.Lubricate cylinder head bolts.
5.Fit and tighten cylinder head bolts to the correct
torque and in the correct sequence.
NOTE: For torque values.See
Specifications, torque, Torque values
6.Fit timing belt.
7.Fit camshaft covers.
8.Fit spark plug leads to spark plugs and secure to
clips.
9.Fit spark plug cover and secure with screws.
10.Fit new gasket and secure downpipe to exhaust
manifold with nuts.
11.Fit bolt securing dipstick tube to coolant rail.
12.Connect 3 vacuum hoses to inlet manifold.
13.Connect fuel to pressure regulator, secure with
clip.
14.Connect fuel injection harness, inlet manifold air
temperature sensor and fuel temperature sensor
multiplugs.
15.Secure engine harness to manifold with bolts.
16.Connect brake servo hose to manifold, secure
with clip.
17.Connect air cleaner hose to throttle housing,
secure with clip.
18.Connect stepper motor and throttle
potentiometer multiplugs.
19.Fit and adjust throttle cable.
20.Connect oxygen sensor multiplug, secure with
cable tie.
21.Connect the bypass and top hose, secure with
clips.
22.Connect coolant temperature sensor multiplugs,
secure with cable tie.
23.Connect hose to heater rail and secure with clip.
24.Connect radiator bottom hose and secure with
clip.
25.Tighten fuel pipe to fuel rail union.
26.Reconnect battery negative lead.

Mpi
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
ENGINE
Timing belt upper cover bolts 5......................................................................
Timing belt centre cover bolts 5.....................................................................
Timing belt lower cover bolts 5......................................................................
Crankshaft pulley centre bolt 85.....................................................................
Crankshaft pulley to timing gear bolts 10........................................................
Tensioner pulley bolt 30..................................................................................
Spark plugs 27................................................................................................
Timing belt upper backplate bolts 10..............................................................
Camshaft gear bolts 65...................................................................................
Exhaust camshaft rear oil seal cover plate bolts 10........................................
Inlet camshaft rear oil seal cover plate bolts 10..............................................
Crankshaft rear oil seal housing bolts 10........................................................
Engine sump bolts
Stage 1 3...............................................................................................
Stage 2 10..............................................................................................
Bell housing nuts 40........................................................................................
L.H. and R.H. engine mounting nuts 85..........................................................
Exhaust manifold to downpipe nuts 10...........................................................
Exhaust downpipe to silencer box nuts 30......................................................
Air conditioning compressor to engine block bolts 45.....................................
Cylinder head bolts
Stage 1 45..............................................................................................
Stage 2 80..............................................................................................
Stage 3 - Further 90°
Camshaft cover bolts 10.................................................................................
Knock sensor 15.............................................................................................
Ignition coil bracket bolts 25............................................................................
Coolant temperature sensor 15......................................................................
Crankshaft sensor bolts 7..............................................................................
Fuel temperature sensor 7.............................................................................
Intake air temperature sensor 7.....................................................................
Fuel rail to inlet manifold bolts 10...................................................................
Fuel feed hose stiffening bracket bolts 7.......................................................
Throttle housing mounting nuts 7...................................................................
Fuel pressure regulator steady bracket bolts 7..............................................
Oxygen sensor 55...........................................................................................

17EMISSION CONTROL
2
FAULT DIAGNOSISADD: 09/95 DRIVE CYCLE - ADVANCED EVAPS
1.Switch on ignition for 30 seconds.
2.Ensure that coolant temperature is less than 140
°F (30°C).
3.Start engine and allow to idle for 2 minutes.
4.Perform 2 light accelerations (0 to 35 mph with
light pedal pressure).
5.Perform 2 medium accelerations (0 to 45 mph
with moderate pedal pressure).
6.Perform 2 hard accelerations (0 to 55 mph with
heavy pedal pressure).
7.Cruise at 60 mph for 5 minutes.
8.Cruise at 50 mph for 5 minutes.
9.Cruise at 35 mph for 5 minutes.
10.Allow engine to idle for 2 minutes.
11.Connect TestBook and check for fault codes.

Tdi
1
DESCRIPTION AND OPERATION DESCRIPTION
Air intake
The air cleaner is positioned to the right of the engine
and connected by hoses to a cold air intake duct and
the turbocharger inlet. A crankcase breather hose is
fitted between the air cleaner and the separator.
A single stage turbocharger, fitted between the
exhaust manifold and exhaust pipe, is connected by
hoses to the air cleaner and to an intercooler mounted
on the right of the radiator. The intercooler is
connected by a hose to the inlet manifold.
Fuel system
A 89 litre fuel tank is mounted at the rear of the
vehicle beneath the load space floor. The tank is
vented by a 2 way valve in the filler cap.
A mechanical lift pump, driven by the camshaft, is
mounted on the side of the engine.
A fuel filter, fitted with a replaceable element and
incorporating a water separator, is positioned on the
LH side of the bulkhead.
A Bosch Type injection pump, incorporating a cold
start advance unit and a high idle setting is mounted
on the LH side of the engine and is directly driven by
gears from the crankshaft. The pump meters and
distributes fuel to 4 pintle type injectors located in
pre-combustion chambers in the cylinder heads.
A return line passes excess fuel from the injection
pump and injectors back to the fuel tank.
Glow plugs
Four glow plugs are located in the cylinder head,
directly below each injector.Exhaust gas recirculation (EGR)
Exhaust gas recirculation is controlled by the EGR
control unit mounted in the passenger compartment
on the RH 'A' post behind the fascia and receives the
following inputs:
a. Engine temperature from coolant temperature
transmitter in No. 4 cylinder head.
b. Throttle position from the sensor on the injection
pump.
c. Engine speed from the tachometer.
d. EGR valve lift position.
When all correct signals are received, the EGR
solenoid allows vacuum to open the EGR valve and
recirculate a portion of the exhaust gas.

19FUEL SYSTEM
2
DESCRIPTION AND OPERATION FUEL SYSTEM LAYOUT
1. Fuel tank
2. Fuel lift pump
3. Fuel filter
4. Fuel injection pump
5. Spill return line
6. Fuel injectors
7. Sediment plug
FUEL SYSTEM COMPONENT LOCATION
1. Fuel filter bleed screw
2. Fuel filter
3. Turbocharger
4. Wastegate
5. Air cleaner
6. Fuel injector
7. Glow plug
8. Glow plug controller
9. EGR valve and valve lift position sensor
10. Coolant temperature transmitter - EGR and instruments
11. Fuel injection pump
12. EGR throttle position sensor
13. Fuel lift pump
14. Intercooler
15. EGR Control unit

19FUEL SYSTEM
4
DESCRIPTION AND OPERATION OPERATION
Diesel engines operate by compression ignition. The
rapid compression of air in the cylinder during the
compression cycle heats the injected fuel, causing it
to self ignite. During cold starting, automatically
controlled glow plugs assist in raising the temperature
of the compressed air to ignition point.
A cold start advance unit advances the injection timing
to further assist starting. Idle quality is improved by
the high idle setting.
The engine is supplied with pre-compressed air by a
single stage turbocharger.
Exhaust gases passing over a turbine cause it to
rotate, driving a compressor mounted on the turbine
shaft. Air drawn from the cold air intake passes, via
the air cleaner, to the turbocharger where it is
compressed. The compressed air passes to the
cylinders via an intercooler, which reduces the
temperature of the compressed air, increasing its
density.
Fuel is drawn from the tank by a mechanical lift pump
and passes to the injection pump via a filter. In
addition to removing particle contamination from the
fuel, the filter incorporates a water separator, which
removes and stores both bound and unbound water.
The injection pump meters a precisely timed, exact
quantity of fuel to the injectors in response to throttle
variations, injection timing varying with engine speed.
Any excess fuel delivered to the injection pump is not
injected, passing back to the tank via the fuel return
line.
Fuel is injected in a finely atomised form into a
pre-combustion chamber in the cylinder head where it
ignites. The burning fuel expands rapidly into the main
combustion chamber, creating extreme turbulence
which mixes the burning fuel thoroughly with the
compressed air, providing complete combustion.
Cold Starting is assisted by glow plugs, a cold start
advance unit and a high idle setting.Glow plugs
Glow plug operation is controlled by a timer unit, start
relay and resistor. When the ignition is turned on the
timer unit is energised, the glow plugs start to operate
and a warning light on the dashboard illuminates,
remaining illuminated until the glow plugs are
automatically switched off.
The length of time the glow plugs will operate is
dependent on under bonnet temperature, which is
monitored by a sensor located in the timer unit.
Starting the engine results in the power supply to the
glow plugs passing through the resistor, which
reduces their operating temperature. The glow plugs
are cut out either by the temperature sensor in the
timer, or by a microswitch on the injection pump which
operates when the throttle is depressed.
Cold start advance
The cold start advance unit is connected to the engine
cooling system via hoses. It contains a temperature
sensitive element which is retracted when cold and
pulls the advance lever, via cable, towards the rear of
the pump against spring pressure. As coolant
temperature rises, the cold start element expands
releasing tension on the cable and allowing spring
pressure to move the advance lever forwards.

Tdi
5
DESCRIPTION AND OPERATION Exhaust Gas Recirculation (EGR)
Operation of the EGR system is dependent on the
following:
a. Engine temperature - must be between 20°C
and 100°C approx.
b. Engine speed - must be between 630 and 2850
rev/min.
c. Engine load - calculated by throttle position
sensor.
d. EGR valve lift position.
e. Duration of engine idling.
Under varying engine speed and load conditions the
control unit sends a signal to open the vacuum
modulator which allows a vacuum to be applied above
the EGR valve diaphragm, the vacuum supply being
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 to
continually monitor EGR valve lift via a position 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.

19FUEL SYSTEM
6
DESCRIPTION AND OPERATION DESCRIPTION ELECTRONIC DIESEL CONTROL
The Electronic Diesel Control (EDC) 'drive by wire'
system derives its from the replacement of
conventional mechanical controls by electronic
components.
The EDC system supplies the exact amount of fuel to
the engine according to the prevailing engine
operating conditions. To monitor these conditions,
sensors are fitted to the engine to measure engine
parameters. Data from the sensors is received by the
Engine Control Module (ECM) which determines the
exact amount of fuel, injection timing and Exhaust
Gas Recirculation (EGR) required for any running
condition.
Safety and emergency features are built into the
system which protect the engine against overspeed
and overheating damage. In the event of component
failure the system is designed to compensate and
allow emergency start and limp home facilities to
operate. The ECM does this by substituting a default
value for the failed component which may result in a
noticeable loss in power but keeps the engine
running.FUEL SYSTEM COMPONENT LOCATION EDC
1. Vehicle speed sensor
2. No. 4 injector sensor
3. Coolant temperature sensor
4. Boost pressure sensor
5. Electro-pneumatic modulator
6. Airflow sensor
7. Engine speed sensor
8. Brake/clutch switches
9. Injector pump
10. Throttle position sensor
11. Engine control module

Tdi
9
DESCRIPTION AND OPERATION OPERATION EDC
Under start up conditions, signals from the crank
speed and water temperature sensors are relayed to
the ECM to control starting fuel quantity and injection
timing. Once the engine has started the ECM initiates
a 'closed loop' monitoring system for fuel quantity,
injector timing and EGR relative to the appropriate
engine operating conditions.
As driver demand increases, signals from the throttle
position sensor are received by the ECM together with
crank speed and position pulses. The ECM signals
the injection pump to adjust fuel quantity and timing
relative to driver demand.
As engine coolant, fuel and air temperature changes
the ECM will correct fuel delivery and injection timing
for more efficient and accurate running. The ECM will
also make corrections for atmospheric pressure on
injection timing and EGR.
Electronic Control Unit (ECM)
The EDC system is controlled by the ECM located in
the drivers footwell on the 'A' post beneath the fascia.
The unit consists of a microprocessor with integrated
circuits and components and is connected to the main
harness by a 55 pin plug.
Inputs to the ECM from engine sensors control start of
injection, injected fuel quantity, fuel cut-off and EGR.
The ECM will also make corrections for engine
coolant, fuel and air temperature and atmospheric
pressure.Injection pump
The injection pump incorporates actuator controlled
injected fuel quantity and solenoid operated timing
which operate in response to ECM signals against
driver demand, engine speed, temperature and boost
pressure.
A fuel cut-off facility and fuel temperature sensor is
incorporated in the pump.
Injection timing sensor
An inductive sensor in No 4 injector body monitors
needle movement. This forms part of a 'closed loop'
system to control start of injection.
The system measures timing, relating the needle
movement signal to crank position (determined by
flywheel pulses from the engine speed sensor).
Air flow sensor
The Air Flow Sensor is mounted on a bracket
attached to the wheel arch valance, and connected by
hose to the air cleaner and turbo charger inlet.
The unit consists of a flap valve airflow sensor which
measures the fresh air flow into the engine. The
sensor informs the ECM and, provided that the other
conditions are met, will implement EGR.
Engine speed sensor
The engine speed sensor is an active inductive sensor
mounted on the flywheel housing. Pulses from the
sensor activated by radial slots in the flywheel give
engine speed and position information to the ECM.