1995 LAND ROVER DISCOVERY ABS

MFI
9
REPAIR
15.Remove distributor vacuum hose.
16.Release two screws and remove throttle position
sensor.
17.Remove six screws securing plenum chamber.
Remove plenum chamber.
18.Remove air idle air control valve hose.Throttle lever assembly - remove
19.If fitted - unclip cruise control actuator link. Hold
throttle fully open, release link from countershaft
assembly. Carefully return lever assembly to
close throttle.
20.Release tension on inboard throttle spring.
21.Bend back lock washer tabs.
22.Hold throttle stop lever in closed position,
release nut from throttle shaft.
23.Release tension on outboard throttle spring.
24.Remove overtravel spring.

MFI
13
REPAIR 44.Grease new air seal with Admax L3 or
Energrease LS3. Push seal down shaft, into
counterbore until seal is 6.0 mm (0.236 in) below
face of plenum.
Throttle levers and bracket - assemble
45.Fit stop lever to throttle shaft, a new tab washer
and secure with throttle shaft nut.
46.Holding stop lever on stop, tighten throttle shaft
nut securely, bend over tabs to lock nut in
position.
47.Fit inboard throttle return spring noting that small
hooked end of spring is nearest plenum.
48.Locate hooked end of inboard spring on stop
lever. Wind up straight end one full turn and
locate in appropriate slot.
49.Fit countershaft to interconnecting nut of throttle
valve shaft.
50.Secure throttle bracket assembly to plenum.
Secure with three retaining bolts.
51.Ensure hooked end of outboard spring is
retained by lever, wind spring up one full turn
and locate free end in appropriate slot.
52.Fit overtravel spring.
Lightly grease throttle return and overtravel
springs with Admax L3 or Energrease LS3.
NOTE: If new throttle levers have been
fitted, minimum throttle setting of disc
must be checked to ensure it is 90Ê to
bore.53.Using a depth vernier or depth micrometer,
check dimension from mouth of bore to top and
bottom of valve disc. Dimension must be within
0.5 mm (0.019 in) total indicator reading across
diameter of disc.
54.If dimension is out of limits, adjust small set
screw below stop lever.
Refit
55.Reconnect and adjust cruise control actuator
link.
See Actuator Link Setting
56.Clean joint faces of plenum and ram housing.
Apply 'Hylomar' sealant, refit plenum chamber.
Tighten bolts to
26 Nm.
57.Reverse removal procedure.

SFI
7
DESCRIPTION AND OPERATION REV: 09/95 Fuel pressure regulator
The fuel pressure regulator is located at the rear of
the engine in the fuel rail. It consists of a fuel inlet,
outlet, vacuum port and internal diaphragm.
When the engine is under high manifold depression,
the applied vacuum sucks the diaphragm of its seat,
allowing fuel to return to the tank, resulting in a lower
fuel pressure. This is necessary because the high
depression will try to suck the fuel from the injector,
resulting in overfuelling if the pressure remained
constant. Failure will result in a rich mixture at idle but
normal at full load, or a rich mixture resulting in engine
flooding, or a weak mixture. Although the fault will not
illuminate the MIL, faults caused by the failure may be
indicated.Relay module
The engine management system employs a relay
module, which houses the main relay and the fuel
pump relay.
Main relay
The main relay supplies the power feed to the ECM
with a tap off to feed the fuel injectors (8 amps) and
air flow sensor (4 amps). This relay is controlled by
the engine management ECM. This enables the ECM
to remain powered up after ignition is switched off.
During this 'ECM power down routine' the ECM
records all temperature readings and powers the
stepper motor to the fully open position. Failure of this
relay will result in the engine management ECM not
being switched on resulting in engine not starting due
to absence of fuel and ignition.
Fuel pump relay
The fuel pump relay is fed from the ignition relay and
controlled by the engine management ECM. The relay
is activated in ignition key position 2 to prime the fuel
system for a period of time controlled by the ECM.
Failure of this relay will result in no fuel pressure.
Inertia switch
The inertia switch isolates the power supply to the fuel
pump in the event of sudden deceleration. The inertia
switch is located in the engine compartment. It is reset
by depressing the central plunger at the top of the
switch.

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
5
REPAIR FUEL RAIL AND INJECTORS
Service repair no - 19.60.04 - Fuel Rail
Service repair no - 19.60.12 - Injectors
Remove
1.Disconnect battery negative lead.
2.Depressurise fuel system.
See Fuel System -
Depressurise
3.Release plenum chamber and place aside.See
Plenum Chamber
4.Disconnect purge hose, crankcase breather
hose, servo vacuum hose and fuel regulator
hose from ram housing.
5.Remove 6 bolts securing ram housing to inlet
manifold.6.Place small packing block on inlet manifold.
Lever between packing block and ram pipe
housing to break seal.
CAUTION: Do not lever against fuel rail.
7.Remove ram housing.
8.Place cloth over inlet manifold to prevent ingress
of foreign matter.
9.Disconnect 8 injector multiplugs.
10.Disconnect fuel temperature sensor multiplug.
11.Position cloth around fuel feed pipe union to
absorb fuel spillage.
12.Disconnect fuel feed pipe from fuel rail.
13.Plug fuel pipe and rail.
14.Slacken clip securing fuel return hose.

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.

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.