1995 LAND ROVER DISCOVERY coolant

19FUEL SYSTEM
2
DESCRIPTION AND OPERATION REV: 09/95 ENGINE MANAGEMENT SYSTEM COMPONENT
LOCATION - PRE ADVANCED EVAPS
1. Engine control module
2. Ignition coils
3. Fuel pressure regulator
4. Mass air flow sensor
5. Relay module
- Main relay
- Fuel pump relay
6. Engine coolant temperature sensor
7. Camshaft position sensor
8. Throttle position sensor

19FUEL SYSTEM
4
DESCRIPTION AND OPERATION Throttle position sensor (TP Sensor)
The throttle position sensor is mounted on the plenum
chamber and connected directly to the throttle shaft.
The sensor is a variable resistor, the signal from
which (0 - 5V) informs the ECM of the actual position
of the throttle disc. As there is no default strategy,
failure of the sensor will result in poor idle and lack of
throttle response. If failure occurs in the closed
position the engine will only reach 1750 rev/min when
the ECM will initiate overrun fuel cut off. The fault is
indicated by illumination of the malfunction indicator
light (MIL) on North American specification vehicles.
Engine coolant temperature sensor (ECT Sensor)
This sensor consists of a temperature dependant
resistive metal strip. The resistance of the strip varies
considerably with coolant temperature, i.e. from 28K
ohms at - 30°C to 90 ohms at 130°C, and 300 Ohms
at 85°C. The ECT Sensor signal is vital to engine
running, as the correct fuelling is dependant upon
engine temperature i.e. richer mixture at low
temperatures. If the sensor is disconnected or failure
occurs a default value will be supplied to the system.
The initial default value selected will be based on the
value of the air intake temperature. This will increase
to a nominal warmed up value over an individual time,
programmed for each default value. The fault may not
be evident to the driver, there may be a hot restart
problem. The fault is indicated by illumination of the
malfunction indicator light (MIL) on North American
specification vehicles.Intake air temperature sensor (IAT Sensor)
This is another resistive sensor, located in the body of
the air cleaner. The resistance varies with changes in
air temperature. The signal from the IAT Sensor is
used to retard the ignition timing if the air temperature
rises above 55°C. If the sensor is disconnected or
failure occurs a default value will be supplied to the
system. The default value selected will represent
normal operating conditions. The fault may not be
evident to the driver, there may be slight power loss in
high ambient temperatures. The fault is indicated by
illumination of the malfunction indicator light (MIL) on
North American specification vehicles.

19FUEL SYSTEM
8
DESCRIPTION AND OPERATION ADD: 09/95 ENGINE MANAGEMENT SYSTEM COMPONENT
LOCATION - ADVANCED EVAPS
1.Engine control module (ECM)
2.Ignition coils
3.Fuel pressure regulator
4.Mass air flow (MAF) sensor
5.Relay module
- Main relay
- Fuel pump relay
6.Engine coolant temperature (ECT) sensor
7.Camshaft position (CMP) sensor
8.Throttle position (TP) sensor

19FUEL SYSTEM
2
REPAIR ENGINE COOLANT TEMPERATURE SENSOR (ECT
SENSOR)
Service repair no - 18.30.10
Remove
1.Disconnect battery negative lead.
2.Remove spring clip and disconnect ECT sensor
multiplug.
3.Position cloth around ECT sensor to absorb
coolant spillage.
4.Remove ECT sensor.
5.Remove sealing washer and discard.
Refit
6.Clean sealing washer, sensor threads and
sensor location.
7.Coat sensor threads with Loctite 577 and fit new
sealing washer.
8.Fit ECT sensor. Tighten to
20 Nm.
9.Fit spring clip to multiplug and connect multiplug
to ECT sensor.
10.Top up cooling system.
11.Run engine to normal operating temperature.
Check for leaks around ECT sensor.CRANKSHAFT POSITION SENSOR (CKP SENSOR)
Service repair no - 18.30.12
Remove
1.Disconnect battery negative lead.
2.Raise vehicle on ramp.
3.Remove 2 bolts securing sensor/shield to engine
backplate.
4.Remove sensor/shield.
5.Remove shield.
6.Disconnect sensor multiplug and remove sensor.
7.Remove spacer from sensor.
CAUTION: All vehicles have a spacer fitted
to the sensor. Ensure spacer is correctly
refitted.
Refit
8.Clean mating faces.
9.Fit spacer to sensor.
10.Position sensor and connect multiplug.
11.Position shield to sensor and align sensor/shield
to engine backplate.
12.Fit bolts. Tighten to
6 Nm.
13.Lower ramp.
14.Reconnect battery negative lead.

SFI
13
REPAIR PLENUM CHAMBER
Service repair no - 19.22.46
Remove
1.Disconnect battery negative lead.
2.Slacken clip securing intake hose to plenum
chamber and release hose.
3.Remove split pin from throttle cable clevis pin.
4.Remove clevis pin.
5.Release and remove kick down cable clevis pin.
6.Disconnect vacuum hose from cruise actuator.
7.Release throttle cable from abutment bracket.
8.Remove front locknut from kick down cable.9.Release cable from bracket.
10.Disconnect breather hose from plenum.
11.Release clip and disconnect multiplug from
throttle position sensor (TP Sensor).
12.Disconnect multiplug from idle air control (IAC).
13.Remove 6 bolts securing plenum chamber.
14.Release plenum chamber from ram pipe
housing.
15.Fit approved hose clamp to water jacket coolant
hoses.
16.Tighten clamp.
17.Position cloth to absorb coolant spillage.
Do not carry out further dismantling if
component is removed for access only.
18.Slacken clips securing coolant hoses to plenum.

SFI
15
REPAIR REV: 09/95 Refit
25.Ensure all mating surfaces are clean.
26.Fit TP sensor. Ensure drive engages correctly
with throttle spindle.
27.Position clamp plate. Secure TP sensor with
bolts. Tighten to
2 Nm.
28.Using a new gasket, fit IAC. Secure with bolts.
Tighten to
2.3 Nm.
29.Ensure mating faces of water jacket and plenum
chamber are clean.
30.Using a new gasket, fit water jacket. Secure with
bolts. Tighten to
13 Nm.
31.Position throttle linkage bracket, fit and engage
return spring.
32.Secure linkage bracket to plenum chamber with
bolts. Tighten to
8 Nm.
33.Remove cloth from ram housing.
34.Ensure mating faces of plenum chamber and
ram pipe housing are clean.
35.Position plenum chamber. Connect coolant
hoses to water jacket. Secure with clips.
36.Remove clamp from coolant pipes. Remove
cloth.
37.Apply a thin, uniform coating of Loctite 577
sealant to sealing face of plenum chamber.
38.Fit plenum chamber.
39.Fit plenum chamber bolts. Tighten to
24 Nm.
40.Connect multiplugs to TP sensor and IAC.
41.Connect breather hose to plenum chamber.
42.Fit kick down cable to abutment bracket and fit
locknut.
43.Connect throttle cable to abutment bracket.
44.Connect vacuum hose to actuator.
45.Align throttle cable to lever. Fit clevis pin. Secure
clevis pin with split pin.
46.Align kick down cable to lever.
47.Fit clevis pin and secure clip.
48.Connect intake hose and secure with clip.
49.Reconnect battery negative lead.
50.Top up cooling system.RELAY MODULE - PRE ADVANCED EVAPS
Service repair no - 18.30.71
Remove
1.Release module from bracket.
2.Disconnect 2 multiplugs.
3.Remove module.
Refit
4.Reverse removal procedure.

Mpi
1
DESCRIPTION AND OPERATION DESCRIPTION
The Mpi Modular Engine Management System
(MEMS) controls the fuel injection and programmed
ignition systems.
The main features are as follows:
·The Engine Control Module (ECM) controls
programmed ignition and fuel injection. The ECM
incorporates short circuit protection and can
store intermittent faults on certain inputs.
Testbook can interrogate the ECM for these
stored faults.
·The ECM uses the speed/density method of air
flow measurement to calculate fuel delivery. This
method measures the inlet air temperature and
inlet manifold pressure and assumes that the
engine is a calibrated vacuum pump with its
characteristics stored in the ECM
·If certain system inputs fail, the ECM implements
a back-up facility to enable the system to
continue functioning, although at a reduced level
of performance.
·A separate diagnostic connector allows engine
tuning or fault diagnosis to be carried out using
Testbook without disconnecting the ECM
harness connector.
·The ECM harness multiplug incorporates
specially plated pins to minimise oxidation and
give improved reliability.
·The throttle potentiometer requires no
adjustment in service. The following components
supply data for both fuelling and ignition:Ignition system
The ECM determines the optimum ignition timing
based on the signals it receives from the following
sensors:
1.Crankshaft sensor - Engine speed and
crankshaft position.
2.Manifold absolute pressure sensor - Engine load
3.Coolant temperature sensor - Engine
temperature.
4.Manifold absolute pressure sensor - Throttle
closed.
5.Knock sensor - Engine noise and vibration.
MEMS uses no centrifugal or vacuum advance, timing
being controlled by the ECM which is energised by the
main relay, within the relay module. Spark distribution
is achieved by 2 coils mounted at the rear of the
engine and controlled by the ECM.

19FUEL SYSTEM
2
DESCRIPTION AND OPERATION Basic ignition timing
MEMS provides the optimum ignition timing for the
relevant engine speed and load. The speed and
position of the engine is detected by the crankshaft
sensor which is bolted to, and projects through the
engine adapter plate.
The sensor incorporates an armature which runs
adjacent to a reluctor insert in the flywheel, the insert
consisting of 34 poles spaced at 10°intervals, with
two missing poles 180°apart to identify the T.D.C.
positions.
The sensor 'reads' these poles to provide a constant
up-date of engine speed and crankshaft position to
the ECM
The load signal is provided by the manifold absolute
pressure sensor mounted inside the ECM casing
which detects manifold pressure via a hose connected
to the manifold chamber. The sensor converts
pressure variations into graduated electrical signals
which can be read by the ECMIgnition timing compensation
Coolant temperature sensor
When the ECM receives a low engine temperature
signal from the coolant sensor, it provides optimum
driveability and emissions by advancing or retarding
the ignition timing.
Knock sensor
The knock sensor is a capacitive device mounted in
the cylinder block between nos. 2 and 3 cylinders
below the inlet manifold. The sensor monitors noise
and vibration in the engine and passes this
information to the ECM which is able to identify the
characteristics of the knocking and make the
necessary corrections to the ignition timing of
individual cylinders.
Idle speed control
When the throttle pedal is released and the engine is
at idle, the ECM uses the fast response of ignition
timing to assist idle speed control.
When loads are placed on, or removed from the
engine the ECM senses the change in engine speed
and in conjuction with the opening of the throttle disc
by the stepper motor, advances or retards the ignition
timing to maintain the specified idle speed. When load
is removed from the engine and the stepper motor
returns to it's original position, the ignition timing
returns to the idle setting.
NOTE: Due to the sensitivity of this system
the ignition timing will be constantly
changing at idle speed.