1995 LAND ROVER DISCOVERY engine

MFI
1
FAULT DIAGNOSIS ENGINE TUNING
Circuit fault diagnosis may be carried out on all V8i
vehicles, using Testbook. Testbook will guide the
operator by visual prompts through a series of
diagnostic checks.
Before commencing any fault diagnosis, the following
preminary checks must be carried out.
Preliminary checks
CAUTION: Catalyst exhaust: If engine is
misfiring or fails to start within 12 seconds
the cause must be rectified. Failure to do
so will result in irreparable damage to the
catalysts. After rectification the engine must be
run at 1500 rev/min (no load) for 3 minutes to
purge any accumulation of fuel in the system.
1.Check that the inertia fuel shut off switch is not
tripped.
2.Check fuse in main fuse panel.
3.Check for ample fuel in tank.
4.Check air inlet system for possible leaks into the
intake manifold.
5.Check HT cables for correct firing order and
routing.
6.Check ignition timing.
Only when the above checks have been carried out,
should circuit diagnosis begin.
See Electrical
Trouble Shooting Manual.
INJECTOR TESTS
NOTE: Before removing any of the
injectors, remove and examine the spark
plugs, check for consistent colouration of
plugs. A leaking injector will result in the
appropriate spark plug being 'sooted up'.
The following test may only be carried out using
suitable injector test equipment.
Leak Test
Leak test with the injectors closed but pressurise to
2.54 Kgf/cm
2. No injector should leak more than 2
drops of fuel per minute.
Fuel Delivery Test
Fuel delivery test with the injector open and
pressurised as above, fuel delivery from each injector
should be 160-175cc per minute using white spirit, or
180-195cc per minute using petrol at 20°C±2°C.

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.

MFI
3
FAULT DIAGNOSIS FUEL PRESSURE CHECK
In order to check the fuel pressure it is necessary to
first depressurise the fuel system as follows:
WARNING: Under normal operating
conditions the multiport fuel injection
system is pressurised by a high pressure
fuel pump, operating at up to 2.3 to 2.5 bar. When
engine is stationary pressure is maintained within
system. To prevent pressurised fuel escaping and
to avoid personal injury it is necessary to
depressurise multiport fuel injection system
before any service operations are carried out.
If vehicle has not been run there will be a small
amount of residual pressure in fuel line. The
depressurising procedure must still be carried out
before disconnecting any component within the
fuel system.
The spilling of fuel is unavoidable during this
operation. Ensure that all necessary precautions
are taken to prevent fire and explosion.
A Pressure gauge 18G1500
B Fuel tank and pump
C Fuel filter
D Fuel injectors x 8
E Regulator1.Remove fuel pump relay module.
See Repair,
Multiport Fuel Injection Relay
2.Start and run engine.
3.When sufficient fuel has been used to cause fuel
line pressure to drop, injectors will become
inoperative, resulting in engine stall. Switch off
ignition.
4.Disconnect battery negative lead. .
NOTE: Fuel at low pressure will remain in
system. To remove low pressure fuel,
place absorbent cloth around fuel pipe at
the filter during disconnection.
5.Connect the pressure gauge on the outlet from
the filter, located on the chassis under the right
rear wheel arch.
6.Reconnect the battery and turn the ignition to
position II while observing the pressure gauge.
Results
Expected reading 2,39-2,672 kgf/cm
2
Pressure drop-max 0.7 kgf/cm2in one minute.
If pressure is low check that filter is not blocked
and pump is operating satisfactorily. Then
recheck pressure. If pressure is still low renew
regulator.
See Repair, Fuel Pressure
Regulator

19FUEL SYSTEM
2
REPAIR AIR FLOW SENSOR
Service repair no - 19.22.25
Remove
NOTE: The air flow sensor is not a
serviceable item. In event of failure or
damage the complete unit must be
replaced.
1.Disconnect battery negative lead.
2.Release intake hose clamp, disconnect from
sensor.
3.Disconnect multi-plug.
4.Release two clips securing air cleaner to air flow
sensor. Remove sensor from engine
compartment.
Refit
5.Reverse removal procedure. Ensure multi-plug is
firmly reconnected, and hose clamp at the rear
of sensor is securely tightened, to prevent
unmetered air entering engine.THROTTLE POSITION SENSOR
Service repair no - 19.22.49
Remove
1.Disconnect battery negative lead.
2.Disconnect multi-plug from harness.
3.Remove two screws securing sensor to plenum
chamber and carefully pull sensor off throttle
shaft.
4.Remove old gasket.
Refit
5.Fit new gasket.
6.Align sensor and shaft flats, slide sensor on to
throttle shaft. Secure sensor to plenum chamber.
CAUTION: DO NOT operate throttle
mechanism while throttle position sensor
is loosely fitted, damage may be caused to
throttle position sensor wiper track.

19FUEL SYSTEM
4
REPAIR MULTIPORT FUEL INJECTION RELAYS
Service repair no - 19.22.08
The two Multiport fuel injection relays are located in
the RH footwell area behind the 'A' post trim panel.
The fuel injection relays can be identified as follows:
A. Fuel pump relay - Blue base
B. Main relay - Black base
Remove
1.Release front door seal from 'A' post.
2.Remove lower 'A' post trim panel.
3.Pull relay from base.
Refit
4.Reverse removal procedure.ENGINE CONTROL MODULE (ECM)-14 CUX
Service repair no - 19.22.34
NOTE: The ECM is not serviceable, in
event of unit failure it must be replaced.
Remove
1.Remove the fascia right-hand closing panel.
2.Remove the right-hand footwell side panel trim.
3.Disconnect battery negative lead.
4.Release ECM plug retaining clip.
5.Maneouvre the front of the plug (in the direction
of the bold arrow) and detach the other end of
the plug from the retaining peg.
6.Release the two screws securing the ECM to the
right-hand footwell side panel.
7.Withdraw the ECM from the clip.
Refit
8.Refit the ECM securely in the clip and fit the two
screws.
9.Reconnect the ECM harness plug. Ensure that
the plug is pushed firmly into its location and that
the retaining clip secures the plug in position.
10.Reverse removal procedure.

MFI
5
REPAIR INERTIA FUEL SHUTOFF SWITCH
Service repair no - 18.30.35
The inertia fuel shutoff switch is located on the
bulkhead next to the washer reservoir under bonnet
[hood].
Remove
1.Disconnect battery negative lead.
2.Disconnect multiplug from inertia switch.
3.Remove 2 screws securing inertia switch to
mounting bracket.
4.Remove inertia switch.
Refit
5.Position inertia switch to mounting bracket and
secure with screws.
6.Connect multiplug to inertia switch.
7.Reconnect battery negative lead.ENGINE FUEL TEMPERATURE SENSOR
Service repair no - 19.22.08
Remove
NOTE: Fuel leakage will not occur when
sensor is removed from fuel rail, therefore
it is not necessary to depressurise the fuel
system.
1.Disconnect battery negative lead.
2.Disconnect multi-plug from sensor.
3.Release sensor from fuel feed rail.
Refit
4.Reverse removal procedure. Ensure sensor is
tightened securely in fuel rail.

19FUEL SYSTEM
6
REPAIR ENGINE COOLANT TEMPERATURE SENSOR
Service repair no - 19.22.18
Remove
1.Position drain tray to collect coolant spillage.
2.Disconnect multiplug from coolant sensor.
3.Remove sensor from thermostat housing.
4.Remove and discard copper washer.
Refit
5.Fit a new copper washer.
6.Fit sensor and tigten securely.
7.Top-up cooling system.
8.Run engine, check for water leaks around
sensor.DEPRESSURISING FUEL SYSTEM
WARNING: Under normal operating
conditions the Multiport fuel injection
system is pressurised by a high pressure
fuel pump, operating at up to 2.3 to 2.5 bar When
engine is stationary pressure is maintained within
system. To prevent pressurised fuel escaping and
to avoid personal injury it is necessary to
depressurise multiport fuel injection system
before any service operations are carried out.
If vehicle has not been run there will be a small
amount of residual pressure in fuel line. The
depressurising procedure must still be carried out
before disconnecting any component within the
fuel system.
The spilling of fuel is unavoidable during this
operation. Ensure that all necessary precautions
are taken to prevent fire and explosion.
1.Remove fuel pump relay module.
See
Multiport Fuel Injection Relays
2.Start and run engine.
3.When sufficient fuel has been used to cause fuel
line pressure to drop, injectors will become
inoperative, resulting in engine stall. Switch off
ignition.
4.Disconnect battery negative lead.
NOTE: Fuel at low pressure will remain in
system. To remove low pressure fuel,
place absorbent cloth around fuel feed
hose at fuel rail.
5.Disconnect either:
a) Nut and olive at fuel rail
OR
b) Hose at inlet end of fuel filter.
Refit
6.Refit fuel feed hose.
7.Refit fuel pump relay module, reconnect battery.
8.Crank engine (engine will fire in approximately 6
to 8 seconds).

19FUEL SYSTEM
16
REPAIR Refit
1.Clean mating faces of cylinder heads, cylinder
block and intake manifold.
2.Locate NEW seals in position with ends
engaged in notches formed between the cylinder
heads and block.
3.Apply RTV sealant between ends of seals,
cylinder head and block.
4.Fit intake manifold gasket with the word
'FRONT'to the front and open bolts hole to the
front RH side.
5.Fit gasket clamps and tighten bolts finger tight.
6.Locate intake manifold onto cylinder heads,
clean threads of manifold securing bolts.
7.Allow 10 minutes for RTV sealant to cure.
8.Fit manifold bolts finger tight. Working in the
sequence shown tighten the bolts to
38 Nm.
9.Tighten the gasket clamp bolts to18 Nm.
10.Reverse removal procedure.
11.Fill cooling system.
See COOLING SYSTEM,
Repair, Radiator
12.Start engine check for water and fuel leaks.