1997 JAGUAR XJ6 stereo

special electrical device that provides circuit
protection by switching off the ignition and
fuel pump upon impact in the event of vehicle
collision. Later Jaguar models are equipped
with an additional specialised inertia switch.
This later device switches OFF all ignition fed
circuits, locks the fuel filler cap, locks the boot
(only if doors are locked) and unlocks the
doors if they are locked during the accident.
All these functions are directed by the inertia
switch. The inertia switch is located behind
the left kick panel. Refer to Chapter 12 for
more information.
Exhaust system
The exhaust system includes an exhaust
manifold equipped with an exhaust oxygen
sensor, a catalytic converter, an exhaust pipe,
and a silencer.
The catalytic converter is an emission
control device added to the exhaust system to
reduce pollutants. A single-bed converter is
used in combination with a three-way
(reduction) catalyst. See Chapter 6 for more
information regarding the catalytic converter.
2 Fuel pressure relief
1
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system.
Don’t smoke or allow open flames or bare
light bulbs near the work area, and don’t
work in a garage where a natural gas-type
appliance (such as a water heater or a
clothes dryer) with a pilot light is present.
Since petrol is carcinogenic, wear latex
gloves when there’s a possibility of being
exposed to fuel, and, if you spill any fuel on
your skin, rinse it off immediately with soap
and water. Mop up any spills immediately
and do not store fuel-soaked rags wherethey could ignite. The fuel system is under
constant pressure, so, if any fuel lines are
to be disconnected, the fuel pressure in
the system must be relieved first. When
you perform any kind of work on the fuel
system, wear safety glasses and have a
Class B type fire extinguisher on hand.
1Before servicing any fuel system
component, you must relieve the fuel pressure
to minimise the risk of fire or personal injury.
2Remove the fuel filler cap - this will relieve
any pressure built up in the tank.
3Remove the fuel pump relay from the main
relay panel (see illustrations). Note:These
models are equipped with a fuel pump relay
that is located in various areas of the vehicle
depending on the year. On 1988 and 1989
models, the fuel pump relay is under the
glovebox. On 1990 to 1992 models, the fuel
pump relay is in the engine compartment on
the left side, attached to the brake pedal
hanger. On 1993 models, the fuel pump relay
is in the boot. On 1994 models, it’s in the
engine compartment on the right side of the
bulkhead. Refer to the relay location charts in
Chapter 12 for additional information.
4Start the engine and wait for the engine to
stall, then turn the ignition key to Off.
Disconnect the cable from the negativeterminal of the battery before beginning any
work on the fuel system.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
5The fuel system is now depressurised.
Note:Place a rag around the fuel line before
removing any hose clamp or fitting to prevent
any residual fuel from spilling onto the engine.
3 Fuel pump/fuel pressure-
check
2
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. See
the Warning in Section 2.
Note: To perform the fuel pressure test, you
will need to obtain a fuel pressure gauge and
adapter set (fuel line fittings).
Note: On 1988 to 1990 models, the fuel pump
may chatter excessively and the engine may
stall frequently during hot weather. If stalling
occurs, the engine will restart after a cool-
down period. Dual fuel pumps can be installed
by a dealer service department or other
qualified repair facility to remedy this problem.
Preliminary inspection
1Should the fuel system fail to deliver the
proper amount of fuel, or any fuel at all,
inspect it as follows. Remove the fuel filler
cap. Have an assistant turn the ignition key to
the ON position (engine not running) while you
listen at the fuel filler opening. You should
hear a whirring sound that lasts for a couple of
seconds. On 1988 to 1990 models, listen
behind the left rear wheel (external fuel pump)
for the fuel pump sound.
2If you don’t hear anything, check the fuel
pump relay (see illustration 2.3a, b or c)and
4•2 Fuel and exhaust systems
2.3c On 1992 models, the fuel pump relay
is located in the left rear corner of the
engine compartment
3261 Jaguar XJ6 2.3a Relay locations on a 1988 model
2.3b Relay locations on a 1989 model

circuit. If all circuits are intact and not
damaged, check the inertia switch. Note: The
inertia switch is a special device that shuts
down power to the ignition and the fuel pump
in the event of an accident. See Chapter 12 for
checking and resetting procedures for the
inertia switch.
3Remove the relay and check for battery
voltage to the fuel pump relay connector (see
illustration). If there is battery voltage
present, check the relay for proper operation.
Refer to the relay checking procedure in
Chapter 12. Note:If battery voltage is not
available, check for battery voltage to the main
relay(see illustration). Refer to the relay
location diagrams in Chapter 12. The main
relay, which is located next to the fuel pump
relay, supplies voltage to the fuel pump and
ignition system.
4If battery voltage is present, check for
battery voltage directly at the fuel pump
electrical connector (see illustrations), within
two seconds of the ignition key being turned
On. If there is no voltage, check the fuel pump
circuit. If there is voltage present, renew the
pump (see Section 4). Note:It will be
necessary to raise the vehicle and support it
securely on axle stands to gain access to the
fuel pump electrical connectors. Have an
assistant operate the ignition key and be sure
to block the front wheels to avoid any
movement of the vehicle.
Operating pressure check
5Relieve the fuel system pressure (see
Section 2). Detach the cable from the negative
battery terminal.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
6Detach the fuel line from the fuel rail and
connect a fuel pressure gauge(see
illustrations)between the fuel pulsationdamper and the fuel rail. Tighten the hose
clamps securely.
7Attach the cable to the negative battery
terminal. Start the engine.
8Note the fuel pressure and compare it with
the pressure listed in this Chapter’s
Specifications.
9Disconnect the vacuum hose from the fuelpressure regulator and hook up a hand-held
vacuum pump (see illustration)to the port on
the fuel pressure regulator.
10Read the fuel pressure gauge with vacuum
applied to the pressure regulator and also with
no vacuum applied. The fuel pressure should
decrease as vacuum increases (and increase
as vacuum decreases).
Fuel and exhaust systems 4•3
4
3261 Jaguar XJ6 3.3a Checking for battery voltage at the fuel pump relay
connector ( 1989 model)
3.3b Checking for battery voltage to the main relay (1989 model)
3.6a Remove the fuel line from the fuel
pulsation damper . . .
3.4b Check for battery voltage to the
fuel pump on the harness connector near
the fuel tank on models with in-tank
fuel pumps3.4a Remove the rubber boot from the fuel
pump electrical connector and check for
voltage while an assistant turns the
ignition key (1989 model shown)
3.6b . . . then refit the fuel pressure gauge
between the fuel rail and the fuel pressure
damper using a T-fitting

11Reconnect the vacuum hose to the
regulator and check the fuel pressure at idle,
comparing your reading with the value listed
in this Chapter’s Specifications. Disconnect
the vacuum hose and watch the gauge - the
pressure should jump up considerably as
soon as the hose is disconnected. If it
doesn’t, check for a vacuum signal to the fuel
pressure regulator (see Step 14).
12If the fuel pressure is low, pinch the fuel
return line shut (see illustration)and watch
the gauge. If the pressure doesn’t rise, the
fuel pump is defective or there is a restriction
or leak in the fuel feed line, or the pump is
faulty. If the pressure rises sharply, renew the
pressure regulator.
13If the fuel pressure is too high, turn the
engine off. Disconnect the fuel return line and
blow through it to check for a blockage. If
there is no blockage, renew the fuel pressure
regulator.
14Connect a vacuum gauge to the pressure
regulator vacuum hose. Start the engine and
check for vacuum (see illustration). The fuel
pressure regulator receives manifold vacuum
that decreases (increases fuel pressure) when
the engine speed is raised (acceleration). If
there isn’t vacuum present, check for a
clogged hose or vacuum port. If the amount ofvacuum is adequate but the pressure is too
high, renew the fuel pressure regulator.
15Turn the ignition switch to OFF, wait five
minutes and recheck the pressure on the
gauge. Compare the reading with the
specified hold pressure. If the hold pressure is
less than specified:
a) The fuel lines may be leaking.
b) The fuel pressure regulator may be
allowing the fuel pressure to bleed
through to the return line.
c) A fuel injector (or injectors) may be
leaking.
d) The fuel pump may be defective.
4 Fuel pump-
removal and refitting
3
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. See
the Warning in Section 2.
Note 1:On early models (1988 to 1990), an
electric fuel pump is attached to the chassis
next to the fuel tank. On later models (1991 to
1994), the fuel pump is inside the fuel tank.
Note 2: On 1988 to 1990 models, the fuel
pump may chatter excessively and the engine
may stall frequently during hot weather. If
stalling occurs, the engine will restart after a
cool-down period. Dual fuel pumps can be
installed by a dealer service department or
other qualified repair facility to remedy this
problem.
1Remove the fuel tank filler cap to relieve
any pressure in the fuel tank. Relieve the fuel
pressure (see Section 2).
2Disconnect the cable from the negative
terminal of the battery.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
External fuel pumps
3Raise the vehicle and support it securely on
axle stands.
4Disconnect the fuel lines from the fuel pump.
5Disconnect the electrical connectors from
the fuel pump (see illustration 3.4a).
6Remove the fuel pump bracket retaining
nuts (see illustration).
7Carefully withdraw the fuel pump from the
rubber case inside the fuel pump bracket and
angle the fuel pump over the rear suspension
and out near the wheel on the left side of the
vehicle.
8Refitting is the reverse of removal.
In-tank fuel pumps
9Raise the vehicle and support it securely on
axle stands.
10Disconnect the fuel pump and fuel level
sender unit electrical connectors and the fuel
lines.
11Remove the fuel tank from the boot (see
Section 7).
12Disconnect the fuel lines from the evap-
orative flange (see illustration). Remove the
lock ring with a hammer and brass punch,
tapping the lock ring anti-clockwise.
13Withdraw the fuel pump module from the
fuel tank. Note: The fuel pump module is
4•4 Fuel and exhaust systems
3.14 Connect a vacuum gauge to the
vacuum line leading to the fuel pressure
regulator and check the vacuum source4.6 Remove the fuel pump mounting nuts
(arrowed) and slide the fuel pump out of
the rubber casing (1989 model shown)
3261 Jaguar XJ6 3.9 Check fuel pressure without vacuum applied to the fuel
pressure regulator, then with vacuum applied; fuel pressure
should DECREASE as vacuum INCREASES
3.12 Using a pair of pliers, squeeze the return line and observe
the fuel pressure increase (wrap a rag around the fuel line so you
don’t damage it)

tank. If there is any doubt about the
amount of fuel in the tank, drain the fuel
tank completely before attempting this
procedure (Section 7, paragraph 1).
9Disconnect the cable from the negative
terminal of the battery. Disconnect the fuel level
sender unit/fuel pump electrical connector.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
10Using a brass punch, tap on the lock ring
anti-clockwise (see illustration)until the tabs
align with the indentations in the fuel tank.
11Carefully angle the sender unit out of the
opening without damaging the fuel level float
(see illustration).
12Refitting is the reverse of removal.
6 Fuel lines and fittings-
inspection and renewal
2
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. See
the Warning in Section 2.
Note:If there is a distinct knocking noise
coming from the dash when the engine is
idling, the fuel feed hose may have hardened,
restricting fuel flow and causing abnormal
sounds. Replace the fuel inlet (feed) hose with
a new one.
Inspection
1Once in a while, you will have to raise the
vehicle to service or renew some component
(an exhaust pipe hanger, for example).
Whenever you work under the vehicle, always
inspect fuel lines and all fittings and
connections for damage or deterioration.
2Check all hoses and pipes for cracks, kinks,
deformation or obstructions.
3Make sure all hoses and pipe clips attach
their associated hoses or pipes securely to
the underside of the vehicle.4Verify all hose clamps attaching rubber
hoses to metal fuel lines or pipes are a tight fit
between the hoses and pipes.
Renewal
5If you must renew any damaged sections,
use hoses or pipes constructed from exactly
the same material as the section you are
replacing. Do not refit substitutes constructed
from inferior or inappropriate material or you
could cause a fuel leak or a fire.
6Always, before detaching or disassembling
any part of the fuel line system, note the
routing of all hoses and pipes and the
orientation of all clamps and clips to assure
that new sections are identically installed.
7Before detaching any part of the fuel
system, be sure to relieve the pressure in the
tank by removing the fuel tank cap, then
relieve the fuel system pressure (Section 2).
Cover the fitting being disconnected with a
rag to absorb any fuel that may leak out.
7 Fuel tank-
removal and refitting
3
Warning: Petrol is extremely
flammable, so take extra
precautions when you work onany part of the fuel system. See the
Warning in Section 2.
1This procedure is much easier to perform if
the fuel tank is empty. Some models may have
a drain plug for this purpose. If for some reason
the drain plug can’t be removed, postpone the
job until the tank is empty or siphon the fuel
into an approved container using a siphoning
kit (available at most motor factors).
Warning: Do not start the
siphoning action by mouth!
2Remove the fuel filler cap to relieve fuel
tank pressure.
3Detach the battery negative cable.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
4If the tank is full or nearly full, drain the fuel
into an approved container.
5Raise the vehicle and place it securely on
axle stands.
6Remove the filler neck vent tube clamp (see
illustration)and separate the tube from the
fuel filler neck.
7Remove the fuel filler assembly bolts (see
illustration)and slide the large rubber boot
down the neck of the fuel tank. Note:These
vehicles are susceptible to clogging of the fuel
overflow line. If this happens, excess fuel or
4•6 Fuel and exhaust systems
7.6 Remove the clamp that retains the fuel
filler assembly to the filler neck7.7a Remove bolts (arrowed) that retain the
fuel filler assembly to the body and slide the
assembly down the filler neck of fuel tank
3261 Jaguar XJ6 5.10 Use a brass punch and remove the lock ring by tapping on it
in an anti-clockwise direction
5.11 Lift the fuel level sender unit assembly from the fuel tank at
an angle so as not to damage the float or arm

10 Accelerator cable- removal,
refitting and adjustment
3
Removal
1Detach the cable from the negative terminal
of the battery.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
2Loosen the locknut on the threaded portion
of the throttle cable at the throttle body (see
illustration).
3Rotate the throttle lever, then slip the
throttle cable end out of the slot in the lever
(see illustration).
4Detach the throttle cable from the
accelerator pedal (see illustration).
5From inside the vehicle, pull the cable
through the bulkhead.
Refitting and adjustment
6Refitting is the reverse of removal.
7To adjust the cable, fully depress the
accelerator pedal and check that the throttle
is fully opened.
8If not fully opened, loosen the locknuts,
depress accelerator pedal and adjust the
cable until the throttle is fully open.
9Tighten the locknuts and recheck the
adjustment. Make sure the throttle closes fully
when the pedal is released (see illustration).
10After the cable is adjusted, check the
adjustment of the bellcrank. Use a small
clamp and a straight rod or stiff wire (coat
hanger) and attach it to the brake master
cylinder in such a way that the tip acts as a
pointer. Align the pointer with “A” (automatic
transmission) or “M” (manual transmission) on
the bellcrank (see illustration),depending on
what type of transmission is installed in the
vehicle.
11Slowly rotate the bellcrank until it reaches
the throttle stop (wide open throttle) andcheck to make sure the pointer aligns with the
notch in the bellcrank (see illustration).
12If necessary, adjust the position of
the throttle stop using a spanner and turn the
throttle stop screw until the bellcrank reaches
the correct position. Lock the throttle stop
screw in place.
4•8 Fuel and exhaust systems
3261 Jaguar XJ6 10.4 Remove circlip (arrowed) and separate cable from the
accelerator pedal by pulling the pin from the pedal assembly
10.2 Loosen the locknuts on the accelerator cable10.3 Rotate the bellcrank and remove the cable end from the slot
10.9 Make sure the throttle closes completely and there is a
slight amount of flex in the cable
10.10 Attach a strong wire (coat hanger)
to the master cylinder using a clamp and
align it with the notch on the bellcrank

of these sensors and their corresponding
ECU-controlled relays are not contained
within EFI components, but are located
throughout the engine compartment. For
further information regarding the ECU and its
relationship to the engine electrical and
ignition system, see Chapter 6.
12 Electronic Fuel Injection
(EFI) system- check
2
1Check the earth wire connections for
tightness. Check all wiring and electrical
connectors that are related to the system.
Loose electrical connectors and poor grounds
can cause many problems that resemble
more serious malfunctions.
2Check to see that the battery is fully
charged, as the control unit and sensors
depend on an accurate supply voltage in
order to properly meter the fuel.
3Check the air filter element - a dirty or
partially blocked filter will severely impede
performance and economy (see Chapter 1).
4If a blown fuse is found, renew it and see if
it blows again. If it does, search for a shorted
wire in the harness related to the system.
5Check the air intake duct from the MAF
sensor to the intake manifold for leaks, which
will result in an excessively lean mixture. Also
check the condition of the vacuum hoses
connected to the intake manifold.
6Remove the air intake duct from the throttle
body and check for carbon and residue build-
up. If it’s dirty, clean with aerosol carburettor
cleaner (make sure the can says it’s safe for
use with oxygen sensors and catalytic
converters) and a toothbrush.
7With the engine running, place a
stethoscope against each injector, one at a
time, and listen for a clicking sound, indicating
operation (see illustration).8If there is a problem with an injector,
purchase a special injector test light (noid
light) and refit it into the injector electrical
connector (see illustration). Start the engine
and make sure that each injector connector
flashes the noid light. This will test for the
proper voltage signal to the injector.Caution:
If the engine will not start and the noid
light indicates that each injector is
receiving the proper signal, there is a good
possibility that the injector(s) is stuck open
and allowing fuel into the combustion
chamber in excessive amounts. If the spark
plugs are fouled, detach the primary (low
voltage) wires from the ignition coil, disable
the fuel pump by removing the fuel pump
relay (see Section 2), remove the spark plugs
and crank the engine over. If fuel sprays from
the spark plug holes, the engine is flooded
and the fuel must be removed from the
combustion chambers.
9With the engine OFF and the fuel injector
electrical connectors disconnected, measure
the resistance of each injector (see
illustration). Each injector should measure
about 2.0 to 3.0 ohms. If not, the injector is
probably faulty.10The remainder of the system checks
should be left to a Jaguar service department
or other qualified repair workshop, as there is
a chance that the control unit may be
damaged if not performed properly.
13 Electronic Fuel Injection
(EFI) system- component
check and renewal
3
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. See
the Warning in Section 2.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
Throttle body
Check
1Verify that the throttle linkage operates
smoothly.
2Start the engine, detach each vacuum hose
and, using your finger, check the vacuum at
each port on the throttle body with the engine
at idle and above idle. The vacuum available
from the throttle body is ported. Raise the
engine rpm and watch as vacuum increases.
It may be necessary to use a vacuum gauge.
Refer to Chapter 2B for additional information
concerning vacuum checks.
Renewal
Warning: Wait until the engine is
completely cool before
beginning this procedure.
3Detach the cable from the negative terminal
of the battery (see the Cautionat the
beginning of this Section).
4Drain the radiator (see Chapter 1).
4•10 Fuel and exhaust systems
12.9 Using an ohmmeter, measure the
resistance across both terminals
of the injector
3261 Jaguar XJ6 12.7 Use a stethoscope or a screwdriver to determine if the
injectors are working properly - they should make a steady
clicking sound that rises and falls with engine speed changes
12.8 Refit the “noid” light into the fuel injector electrical
connector and check to see that it blinks with the engine running

3261 Jaguar XJ6
5
Chapter 5
Engine electrical systems
Ignition system
Ignition timing (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not adjustable
Ignition coil resistance (at 68°F):
Primary resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.4 to 0.5 ohms
Secondary resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.0 to 6.5 k-ohms
Charging system
Charging voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.9 to 15.1 volts
Standard amperage:
No load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Less than 10 amps
Full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 amps or more Amplifier - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Alternator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Battery cables - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . 4
Battery check, maintenance and charging . . . . . . . . . . . See Chapter 1
Battery - emergency jump starting . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Battery - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Charging system - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Charging system - general information and precautions . . . . . . . . . 10
CHECK ENGINE light . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 6
Distributor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Drivebelt check, adjustment and renewal . . . . . . . . . . . See Chapter 1General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Ignition coil - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Ignition system - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Ignition system - general information and precautions . . . . . . . . . . . 5
Spark plug renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Spark plug lead, distributor cap and rotor check
and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Starter motor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 15
Starter motor - testing in vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Starter solenoid - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 16
Starting system - general information and precautions . . . . . . . . . . 13
5•1
Specifications Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321
1 General information
The engine electrical systems include all
ignition, charging and starting components.
Because of their engine related functions,
these components are discussed separately
from chassis electrical devices such as the
fuses, relays, lights, etc. (which are included in
Chapter 12).
Always observe the following precautions
when working on the electrical systems:
a) Be extremely careful when servicing
engine electrical components. They are
easily damaged if checked, connected or
handled improperly.
b) Never leave the ignition switch on for long
periods of time (10 minutes maximum)
with the engine off.c) Don’t disconnect the battery cables while
the engine is running.
d) Maintain correct polarity when connecting
a battery cable from another vehicle
during jump starting.
e) Always disconnect the negative cable first
and hook it up last or the battery may be
shorted by the tool being used to loosen
the cable clamps.
It’s also a good idea to review the safety-
related information regarding the engine
electrical systems in the Safety first section
near the front of this manual before beginning
any operation included in this Chapter.
2 Battery-
emergency jump starting
1
See “Jump starting”in “Roadside repairs”
at the front of this Manual.
3 Battery- removal and refitting
1
1Disconnect the negative terminal, then the
positive terminal from the battery. On 1989 to
1992 models, the battery is located in the
engine compartment on the passenger side
bulkhead and on 1993 and 1994 models, it is
located in the boot.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
2Remove the battery hold-down clamp.
3Lift out the battery. Be careful, it’s heavy.
4While the battery is out, inspect the carrier
(tray) for corrosion.
5If you are replacing the battery, make sure
that you get one that’s identical, with the

same dimensions, amperage rating, cold
cranking rating, etc. as the original.
6Refitting is the reverse of removal.
4 Battery cables-
check and renewal
1
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
1Periodically inspect the entire length of
each battery cable for damage, cracked or
burned insulation and corrosion. Poor battery
cable connections can cause starting
problems and decreased engine performance.
2Check the cable-to-terminal connections at
the ends of the cables for cracks, loose wire
strands and corrosion. The presence of white,
fluffy deposits under the insulation at the
cable terminal connection is a sign that the
cable is corroded and should be renewed.
Check the terminals for distortion, missing
mounting bolts and corrosion.
3When removing the cables, always
disconnect the negative cable first and hook it
up last or the battery may be shorted by the
tool used to loosen the cable clamps. Even if
only the positive cable is being renewed, be
sure to disconnect the negative cable from
the battery first (see Chapter 1 for further
information regarding battery cable removal).
4Disconnect the cables from the battery,
then trace each of them to their opposite ends
and detach them from the starter solenoid
and earth terminals. Note the routing of each
cable to ensure correct refitting.
5If you are replacing either or both of the old
cables, take them with you when buying new
items. It is vitally important that you replace
the cables with identical parts. Cables have
characteristics that make them easy to
identify: positive cables are usually red, larger
in cross-section and have a larger diameter
battery post clamp; earth cables are usually
black, smaller in cross-section and have a
slightly smaller diameter clamp for the
negative post.
6Clean the threads of the solenoid or earth
connection with a wire brush to remove rust
and corrosion. Apply a light coat of battery
terminal corrosion inhibitor, or petroleum jelly,
to the threads to prevent future corrosion.
7Attach the cable to the solenoid or earth
connection and tighten the mounting nut/bolt
securely.
8Before connecting a new cable to the
battery, make sure that it reaches the battery
post without having to be stretched.
9Connect the positive cable first, followed by
the negative cable.
5 Ignition system- general
information and precautions
1All models are equipped with a computerised
ignition system. The ignition system consists of
the ignition coil, the crankshaft position sensor,
the amplifier and the electronic control unit
(ECU). The ignition ECU controls the ignition
timing and advance characteristics for the
engine. The ignition timing is not adjustable,
therefore, changing the position of the distributor
will not change the timing in any way. Note:In
the event the distributor must be removed from
the engine, be sure to follow the precautions
described in Section 9 and mark the engine and
distributor with paint to ensure correct refitting. If
the distributor is not marked and Ihe crankshaft is
turned while the distributor is out of the engine,
have the distributor installed by a dealer service
department. The distributor must be installed
using a special alignment tool.
2The distributor is driven by the intermediate
shaft which also drives the power steering pump.
The crankshaft position sensor is located on the
front timing cover. It detects crank position by
pulsing an electronic signal to the ECU. This
signal is sent to the ECU to provide ignition
timing specifications.
3The computerised ignition system provides
complete control of the ignition timing by
determining the optimum timing in response to
engine speed, coolant temperature, throttle
position and vacuum pressure in the intake
manifold. These parameters are relayed to the
ECU by the crankshaft position sensor, throttle
potentiometer, coolant temperature sensor and
MAF sensor. Ignition timing is altered during
warm-up, idling and warm running conditions by
the ECU. This electronic ignition system also
consists of the ignition switch, battery, coil,
distributor, spark plug leads and spark plugs.
4Refer to a dealer parts department or car
accessory outlet for any questions concerning
the availability of the distributor parts and
assemblies. Testing the crankshaft position
sensor is covered in Chapter 6.
5When working on the ignition system, take
the following precautions:
a) Do not keep the ignition switch on for
more than 10 seconds if the engine will
not start.
b) Always connect a tachometer in
accordance with the manufacturer’s
instructions. Some tachometers may be
incompatible with this ignition system.
Consult a dealer service department
before buying a tachometer for use with
this vehicle.
c) Never allow the ignition coil terminals to
touch earth. Earthing the coil could result
in damage to the igniter and/or the
ignition coil.
d) Do not disconnect the battery when the
engine is running.
6 Ignition system- check
2
Warning: Because of the high
voltage generated by the
ignition system, extreme care
should be taken when working
on the ignition components. This not only
includes the amplifier, coil, distributor and
spark plug leads, but related components
such as connectors, tachometer and other
test equipment also.
1With the ignition switch turned to the “ON”
position, a “Battery” light or an “Oil Pressure”
light is a basic check for ignition and battery
supply to the ECU.
2Check all ignition wiring connections for
tightness, cuts, corrosion or any other signs of a
bad connection.
3Use a calibrated ignition tester to verify
adequate secondary voltage (25,000 volts) at
each spark plug (see illustration). A faulty or
poor connection at that plug could also result in a
misfire. Also, check for carbon deposits inside
the spark plug boot.
4Check for carbon tracking on the coil. If
carbon tracking is evident, renew the coil and be
sure the secondary wires related to that coil are
clean and tight. Excessive wire resistance or
faulty connections could damage the coil.
5Check for battery voltage to the ignition coil
(see illustration). If battery voltage is available,
check the ignition coil primary and secondary
resistance (see Section 8).
6Check the distributor cap for any obvious
signs of carbon tracking, corroded terminals or
cracks (see Chapter 1).
7Using an ohmmeter, check the resistance of
the spark plug leads. Each wire should measure
less than 25,000 ohms.
8Check for battery voltage to the ignition
amplifier (see Section 7). If battery voltage does
not exist, check the circuit from the ignition
switch (refer to the wiring diagrams at the end of
Chapter 12).
5•2 Engine electrical systems
6.3 To use a calibrated ignition tester
(available at most car accessory outlets),
remove a plug lead from a cylinder,
connect the spark plug boot to the tester
and clip the tester to a good earth - if there
is enough voltage to fire the plug, sparks
will be clearly visible between the
electrode tip and the tester body
3261 Jaguar XJ6