spark plugs LAND ROVER DISCOVERY 1995 User Guide

12ENGINE
10
REPAIR ROCKER COVER GASKET - LEFT HAND
Service repair no - 12.29.40 - LH Cover Gasket
Service repair no - 12.29.41 - RH Cover Gasket
Remove
1.Disconnect battery negative lead.
2.Remove plenum chamber.
See FUEL SYSTEM
SFI, Repair, Plenum Chamber
3.Remove screw securing dipstick tube to rocker
cover.
4.Release plug leads from guide clips and
disconnect from 4 spark plugs.
5.Remove 4 bolts securing rocker cover to cylinder
head.
6.Remove rocker cover.
7.Remove and discard rocker cover gasket.
Refit
8.Clean mating faces between rocker cover and
cylinder head using Bostick cleaner 6001 or
equivalent. Allow to dry.
NOTE: Gasket fits one way round only. It
must be fitted accurately, first time.
Subsequent movement will destroy
bonding.
9.Apply a thin coating of impact adhesive (Bostick
1775 or equivalent) to mating faces of rocker
cover seal face and new gasket. Use a brush to
ensure an even film. Allow adhesive to become
touch dry.
10.Place one end of gasket into cover recess with
edge firmly against recess wall, holding
remainder of gasket clear. Work around cover,
pressing gasket into place ensuring edge firmly
contacts recess wall.
CAUTION: Allow cover to stand for thirty
minutes before fitting.
11.Fit rocker cover to cylinder head, ensure short
screws are inboard. Tighten to
9 Nm.
12.Connect leads to spark plugs and secure to
guide clips on rocker cover.
13.Secure dipstick tube to rocker cover.
14.Refit plenum chamber.
See FUEL SYSTEM
SFI, Repair, Plenum Chamber
15.Reconnect battery negative lead.

Mpi
13
REPAIR 19.Connect crankshaft sensor, knock sensor, air
conditioning compressor, fuel injector harness,
inlet manifold air temperature and fuel
temperature sensor multiplugs.
20.Connect fuel hose to pressure regulator and
secure with clip.
21.Fit and tighten fuel pipe to fuel rail union.
22.Connect multiplugs to throttle housing.
23.Connect vacuum hose to manifold.
24.Connect oil pressure switch multiplug.
25.Connect brake servo hose to manifold, secure
with clip.
26.Connect throttle cable to cam.
27.Position engine harness and connect breather
hose to inlet manifold, secure with clip.
28.Connect coolant temperature sensor multiplugs,
secure harness with cable tie.
29.Connect oxygen sensor multiplug, secure
harness with cable tie.
30.Connect alternator harness.
31.Connect heater hose to heater rail and secure
with clip.
32.Connect hose to coolant pump and secure with
clip.
33.Connect inlet hose to power steering pump and
secure with clip.
34.Fit and tighten outlet pipe union to power
steering pump.
35.Connect bypass and top hose, secure with clip.
36.Connect air cleaner to throttle housing hose and
secure with clip.
37.Remove engine lifting bracket.
38.Position spark plug cover and secure with
screws.
39.Fill engine with oil.
40.Fit bonnet [hood].
See CHASSIS AND BODY,
Repair, Bonnet [Hood]
41.Fit radiator.See COOLING SYSTEM, Repair,
Radiator - Mpi
42.Adjust throttle cable.See FUEL SYSTEM,
Adjustment, Throttle Cable Adjustment
ENGINE SUMP GASKET
Service repair no - 12.60.43
Remove
1.Drain engine oil.
2.Refit drain plug, use new sealing washer if
necessary, tighten to the correct torque.
3.Remove 18 bolts securing sump.
NOTE: 25mm long bolt is fitted at rear L.H.
corner of sump.
4.Release sump from cylinder block.
5.Discard gasket.

Mpi
17
REPAIR 22.Raise vehicle
23.Remove 4 nuts securing downpipe to exhaust
manifold.
24.Release downpipe from exhaust manifold.
25.Collect gasket.
26.Release 4 screws and remove spark plug cover.
27.Release spark plug leads from spark plugs and
release from clips. Place aside.
28.Remove camshaft covers.
29.Remove timing belt.
See Camshaft Front Oil
Seal
30.Progressively loosen and remove 10 cylinder
head bolts in sequence shown.
31.Remove cylinder head complete with manifold,
place on blocks to prevent damage.
32.Remove and discard cylinder head gasket.
33.Remove location dowels from cylinder block.
34.Inspect cylinder head for damage, cracks and
burning.
35.Inspect cylinder block. Ensure that the oil
restrictor is clear and fitted below the block face.
36.Clean all traces of gasket material from head
and block mating faces, using release agent and
plastic scraper.
37.Check cylinder head and block faces for
warpage:
Longitudinal warp = 0.1 mm max.
Transverse warp = 0.1 mm max.
Diagonal warp = 0.1 mm max.
38.Decarbonize cylinder head and pistons if
necessary.
39.Clean cylinder head bolt threads with a wire
brush, check for damage, replace if necessary.
40.Check cylinder block threads by running bolts
into threads using fingers only. Clean any tight
threads using M11 x 1.5 mm tap. Remove all
traces of oil from bolt holes.

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...........................................................................................

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.

86ELECTRICAL
2
FAULT DIAGNOSIS LUCAS CONSTANT ENERGY IGNITION SYSTEM -
V8i
Preliminary checks
Inspect battery cables and connections to ensure they
are clean and tight. Check electrical condition of
battery.
Inspect all L.T. connections, ensure they are clean
and tight. Check H.T. leads are correctly positioned
and not shorting to ground against any engine
components. Wiring harness and individual cables
should be firmly fastened to prevent chaffing.
Pick-up air gap
Check air gap between pick-up limb and reluctor teeth
is 0.20 - 0.35 mm, using a non-ferrous gauge.
NOTE: Air gap is set initially at factory and
will only require adjusting if tampered with
or when pick-up module is replaced.
TEST 1:
H.T. Sparking
Remove coil/distributor H.T. lead from distributor
cover and hold approximately 6mm from engine block,
using suitable insulated pliers. Switch ignition 'On' and
operate starter.
Regular sparking indicates fault in H.T. distribution,
plugs, timing or fuelling, proceed to Test 6. If no spark
or weak spark occurs proceed to Test 2.TEST 2:
L.T. Voltage
Switch ignition 'On' - engine stationary.
(a) Connect voltmeter to points in circuit indicated
by V1 to V4 and make a note of voltage
readings.
(b) Compare voltages obtained with specified
values listed below:
Expected readings
V1 More than 12 volts.
V2 1 volt maximum below volts at V1.
V3 1 volt maximum below volts at V1.
V4 0 volt - 0.1 volt.
(c) If all readings are correct proceed to Test 3.
(d) Check incorrect reading(s) with chart to identify
area of possible faults, i.e. faults listed under
heading SUSPECT and rectify.
(e) If coil and amplifier is suspected, disconnect L.T.
lead at coil, repeat V3. If voltage is still incorrect,
fit new coil. If voltage is now correct, check L.T.
lead, if satisfactory fit new amplifier.
(f) If engine will not start proceed to Test 3.

ELECTRICAL
5
FAULT DIAGNOSIS TEST 6:
Rotor Arm
Remove distributor cover. Disconnect coil H.T. lead
from cover, using insulated pliers hold about 3mm
above rotor arm electrode and crank the engine.
There should be no H.T. sparking between rotor and
H.T. lead. If satisfactory carry out Test 7.
If H.T. sparking occurs, an earth fault on rotor arm is
indicated. Fit new rotor arm. If engine will not start
carry out Test 7.
TEST 7:
Visual and H.T. Cable Checks
Examine: Should be:
1. Distributor Cover Clean, dry, no tracking marks.....................................................
2. Coil Top Clean, dry, no tracking marks....................................................................
3. H.T. Cable Insulation Must not be cracked, chafed or perished...............................................
4. H.T. Cable Continuity Must not be open circuit..............................................
5. Sparking Plugs Clean, dry, and set to correct gap........................................................
NOTE:
1. Reluctor Must not foul pick-up or leads...................................................................
2. Rotor and Insulation Cover Must not be cracked or show signs of tracking marks.....................................