air conditioning LAND ROVER DISCOVERY 1995 Owner's Manual

Tdi
7
REPAIR
9.Move intercooler upwards and clear of fan cowl.
Refit
10.Ensure locatiing lug grommets are fitted and in
good condition.
11.Ensure foam pad is in good condition and
attached to intercooler.
12.Move intercooler into position.
13.Reverse removal procedure.GLOW PLUGS
Service repair no - 19.60.31
Remove
1.Disconnect battery negative lead.
No.1 glow plug - air conditioning models
2.Release drive belt from compressor pulley.See
ENGINE, Repair, Drive Belt Renew
3.Remove 4 bolts securing compressor to front
cover, move compressor aside.
No.3 glow plug
4.Remove bolt securing Hummel valve, withdraw
valve, remove and discard 'O' ring.

19FUEL SYSTEM
8
REPAIR
All glow plugs
5.Remove terminal nut from glow plug, disconnect
wire from glow plug terminal.
6.Remove glow plug.
Refit
7.Clean glow plug and seating.
8.Coat threads of glow plug with suitable anti-seize
compound operational to a temperature of
1000°C.
9.Fit glow plug. Tighten to
23 Nm.
10.Connect wire to glow plug terminal and secure
with nut.
NOTE: Feed wire must be connected to
No. 4 glow plug terminal.
11.
No. 3 glow plug:Lubricate new 'O' ring with
engine oil and fit to Hummel valve. Fit valve and
secure with bolt. Tighten to
15 Nm.
No. 1 glow plug - air conditioning models
12.Position compressor to front cover, fit bolts.
Tighten to
25 Nm.
13.Fit drive belt to compressor pulley and adjust
tension.
See ENGINE, Repair, Drive Belt
Renew
All models
14.Reconnect battery negative lead.EGR VALVE
Service repair no - 19.45.01
Remove
1.Disconnect multiplug from EGR valve.
2.Disconnect vacuum pipe from EGR valve.
3.Remove 2 Allen screws securing EGR valve to
exhaust manifold.
4.Remove 2 bolts securing hose to EGR valve.
5.Remove EGR valve and discard gaskets.
Refit
6.Clean mating faces of EGR valve and exhaust
manifold.
7.Reverse removal procedure. Tighten bolts to
25
Nm.

19FUEL SYSTEM
2
FAULT DIAGNOSIS BASE IDLE SPEED SETTING
NOTE: Base idle speed is set at factory. It
should not require further adjustment
unless plenum chamber is changed. The
adjustment screw is sealed with a plug to prevent
unauthorised alteration. Check ignition timing
before attempting following procedure, since this
will affect idle speed.
Equipment required
Two blanking hoses.these are manufactured using
a new air by-pass valve hose - Part No.ETC7874. Cut
two equal pieces 90mm long from hose and seal one
end of each, using 13mm diameter bar. Use a suitable
clamp to ensure an air tight seal.
Checking procedure
1.Drive vehicle at least two miles until engine and
transmission are hot. Switch off engine.
2.Check all electrical loads are OFF, including air
conditioning.
3.Remove air by-pass valve hose.
4.Fit blanking hoses to both plenum chamber and
air by-pass valve. Ensure hoses are securely
fitted to prevent air leaks. Note throttle cable and
cruise control actuator have been omitted from
illustration.5.Start engine and check idle speed is within
limits.
See ENGINE TUNING DATA,
Information, Engine 3.9 v8i
Adjusting base idle speed
6.Drill tamper proof plug and insert a self tapping
screw to enable plug to be extracted.
7.Start engine, adjust idle screw clockwise to
decrease or counter-clockwise to increase idle
speed.
8.Stop engine, remove blanking hoses. Reconnect
hose to plenum.
9.Fit new tamper proof plug.

SFI
1
ADJUSTMENT ENGINE TUNING
Service repair no - 19.22.13
The position of the Idle Air Control (IAC) valve can be
checked using TestBook and adjusted if necessary
through the by-pass screw in the plenum chamber.
The bypass screw is covered by a tamper proof plug
which can be extracted using a self tapping screw.
All vehicles:
1.Ensure air conditioning and all electical loads are
off. Vehicle must be in neutral or park with air
suspension in kneel and disabled.
2.Carry out tuning or base idle setting procedure
as applicable using TestBook.

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

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1
FAULT DIAGNOSIS ENGINE OVERHEATING
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Is coolant level correct?
NO - Allow engine to cool, top up level to
expansion tank seam.
YES - Continue.
2.Is drive belt tension correct?
NO -
See ENGINE, Repair, Compressor
Drive Belt
YES - Continue.
3.Is coolant in radiator frozen?
YES - Slowly thaw and drain system.
See
Adjustment, Coolant
NO - Continue.
4.Is air flow through radiator restricted or blocked?
YES - Apply air pressure from engine side of
radiator to clear obstruction.
NO - Continue.
5.Are there any external leaks, from water pump,
engine gaskets, fast idle thermostat or the heater
unit?
YES - Investigate and rectify.
See Adjustment,
Coolant
NO - Continue.
6.Are fan blades fitted correct way round, concave
side towards engine?
NO - Rectify.
YES - Continue
7.Is viscous unit operating correctly?
See
Description and operation, Viscous Fan
NO - Renew.See Repair, Viscous
Coupling, Fan Blades, Pulley and Fan
Cowl
YES - Carry out a pressure test on radiator cap
and system. Check thermostat type,
operation and correct fitting.
See Repair,
Thermostat
If pressure test leads you to suspect coolant
leakage across gaskets, go to check 10,
otherwise: Continue.8.Are the air conditioning fans operating correctly?
See Electrical Trouble Shooting Manual.
NO - Rectify.
YES - Continue.
9.Is temperature sender and gauge giving
accurate readings?
NO - Sustitute parts and compare readings.
YES - Continue.
10.Carry out cylinder pressure test to determine if
pressure is leaking into cooling system causing
over pressurising and loss of coolant.
If problem is not diagnosed, check the coolant system
for engine oil contamination and engine lubrication
system for coolant contamination.
If only the coolant system is contaminated suspect a
cylinder head gasket.
If both systems are contaminated, suspect the
radiator.
If only the lubrication system is contaminated with
coolant, suspect leakage past cylinder liner seals or
cylinder head gasket.

26COOLING SYSTEM
2
FAULT DIAGNOSIS ENGINE RUNS COLD
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Check operation of viscous unit.See
Description and operation, Viscous Fan
Is viscous unit operating correctly?
NO -
See Repair, Viscous Coupling, Fan
Blades, Pulley and Fan Cowl
YES - Continue.
2.Is thermostat correct type and operating?
See
Repair, Thermostat
If problem is not diagnosed: Continue.
3.Are the air conditioning fans operating
continuously?
YES -
See Electrical Trouble Shooting
Manual.
NO - Continue.
4.Is temperature sender and gauge giving
accurate readings? Substitute parts and
compare readings. If problem is not diagnosed
repeat tests, starting at 1.

Tdi
1
REPAIR VISCOUS COUPLING, FAN BLADES, PULLEY AND
FAN COWL
Service repair no - 26.25.03/05
Viscous coupling -Remove1to3
Fan blades -Remove1to4
Fan cowl -Remove1to3
Fan pulley -Remove1to6
Remove
WARNING: Disconnect battery negative
terminal to prevent engine being started
before removing or adjusting drive belt.
1.Slacken nut securing viscous coupling/fan blade
assembly to pulley.
NOTE: Nut securing viscous unit to pulley
has a left hand thread. Release by turning
clockwise when viewed from front of
viscous unit.
2.Drop viscous unit and fan assembly into bottom
of cowling
3.Remove two fixings clips from top of cowling and
lift cowling complete with viscous unit and fan
out of lower mountings.
4.Remove fan blades from viscous coupling if
necessary.
5.Remove serpentine drive belt and, if fitted, air
conditioning compressor belt.
6.Remove pulley fixings, remove pulley.
NOTE: The serpentine belt is removed by
using a hexagonal socket and tommy bar
on the auto-tensioning pulley nut. Whilst
tensioning the device the belt can be removed.
7.Reverse removal procedure. Ensure fan blades
are fitted correctly. Fan is marked 'front' and
should be fitted with word 'front' closest to
radiator. Tighten to
30 Nm.
8.Refit drive belt.See ENGINE, Repair, Drive
Belt
THERMOSTAT
Service repair no - 26.45.01
Remove
1.Partially drain cooling system, until coolant level
is below thermostat housing.
2.Disconnect hose from thermostat housing.
3.Disconnect electrical connections to water
temperature switch.
4.Remove outlet elbow.
5.Withdraw thermostat.
Test
6.Note rating of thermostat is 88°C. Place
thermostat in a container half full of water. Heat
water, observe temperature at which thermostat
begins to open. Thermostat is satisfactory if its
open between 85°C and 89°C.
Refit
7.Insert thermostat with jiggle pin/vent hole upper
most (12 o'clock position) .
8.Fit the outlet elbow and new joint washer.
Tighten to
28 Nm.
9.Reverse removal procedure. 1 to 3.
10.Check for coolant leaks around all connections
and joint faces.

V8i
1
FAULT DIAGNOSIS ENGINE OVERHEATING
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Is coolant level correct?
NO - Allow engine to cool, top up level to
expansion tank seam.
YES - Continue.
2.Is drive belt tension correct?
NO -
See ENGINE, Repair, Drive Belt -
Check Tension
YES - Continue.
3.Is ignition timing correct?
NO -
See ELECTRICAL, Adjustment,
Ignition Timing
YES - Continue.
4.Is coolant in radiator frozen?
YES - Slowly thaw and drain system.
See
Adjustment, Coolant Requirements
NO - Continue.
5.Is air flow through radiator restricted or blocked?
YES - Apply air pressure from engine side of
radiator to clear obstruction.
NO - Continue.
6.Are there any external leaks, from water pump,
engine gaskets or the heater unit?
YES - Investigate and rectify.
See Adjustment,
Coolant Requirements
NO - Continue.
7.Are fan blades fitted correct way round, concave
side towards engine?
NO - Rectify.
YES - Continue.8.Is viscous unit operating correctly?
See
Description and operation, Viscous Fan
NO - Renew.See Repair, Viscous
Coupling, Fan Blades, Pulley and Fan
Cowl
YES - Carry out a pressure test on radiator cap
and system. Check thermostat type,
operation and correct fitting
See Repair,
Thermostat
If pressure test leads you to suspect coolant
leakage across gaskets, go to check 11,
otherwise: Continue.
9.Are the air conditioning fans operating correctly?
See Electrical Trouble Shooting Manual.K5
NO - Rectify.
YES - Continue.
10.Is temperature sender and gauge giving
accurate readings?
NO - Substitute parts and compare readings.
YES - Continue.
11.Carry out cylinder pressure test to determine if
pressure is leaking into cooling system causing
over pressurising and loss of coolant.
If problem is not diagnosed, check the coolant system
for engine oil contamination and engine lubrication
system for coolant contamination.
If the coolant only, or both systems are contaminated,
suspect cylinder head gaskets or radiator.
If only the lubrication stystem is contaminated with
coolant, suspect inlet manifold or front cover gaskets.

26COOLING SYSTEM
2
FAULT DIAGNOSIS ENGINE RUNS COLD
Before conducting any cooling system diagnosis:
See
Description and operation, Engine cooling
1.Check operation of viscous unit.See
Description and operation, Viscous Fan
Is viscous unit operating correctly?
NO -
See Repair, Viscous coupling, fan
blades, pulley and fan cowl
YES - Continue.
2.Is thermostat correct type and operating?
See
Repair, Thermostat
If problem is not diagnosed: Continue.
3.Are the air conditioning fans operating
continuously?
YES -
See Electrical Trouble Shooting
Manual.
NO - Continue.
4.Is temperature sender and gauge giving
accurate readings? Substitute parts and
compare readings. If problem is not diagnosed
repeat tests, starting at 1.