1997 JAGUAR XJ6 air suspension

16 Spark plug renewal
2
Refer to Section 4, renewing the plugs
regardless of their apparent condition.
17 Air cleaner element renewal
1
1The air filter is located inside a housing at
the left side of the engine compartment. To
remove the air filter, release the four spring
clips that secure the two halves of the air
cleaner housing together, then lift the cover
up and remove the air filter element (see
illustration).
Caution: Never drive the car with the air
cleaner removed. Excessive engine wear
could result and backfiring could even
cause a fire under the bonnet.
2Wipe out the inside of the air cleaner
housing.
3Place the new filter into the air cleaner
housing, making sure it seats properly.
4Refitting the cover is the reverse of removal.
18 Fuel filter renewal
2
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-typeappliance (such as a water heater or
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 where
they 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 (see
Chapter 4 for more information). When you
perform any kind of work on the fuel
system, wear safety glasses and have a
Class B type fire extinguisher on hand.
1The canister type filter is mounted
underneath the car on the passenger’s side
frame rail just in front of the left rear tyre.
2Depressurise the fuel system (refer to
Chapter 4), then disconnect the cable from
the negative terminal of the battery.
3On 1988 to 1990 models, detach the banjo
bolt from the outlet side of the filter then
remove the union from the inlet side of the
filter. Unscrew the filter mounting bolt and
remove the filter (see illustration).
4On 1991 to 1994 models, the fuel filter has
quick-disconnect fittings that do not require 8Clean and lubricate the handbrake cable,
along with the cable guides and levers. This
can be done by smearing some of the chassis
grease onto the cable and its related parts
with your fingers.
9Open the bonnet and smear a little chassis
grease on the bonnet latch mechanism. Have
an assistant pull the bonnet release lever from
inside the car as you lubricate the cable at the
latch.
10Lubricate all the hinges (door, bonnet,
etc.) with engine oil to keep them in proper
working order.
11The key lock cylinders can be lubricated
with spray graphite or silicone lubricant, which
is available at motor factors.12Lubricate the door weather-stripping with
silicone spray. This will reduce chafing and
retard wear.
15 Road test
1
Instruments and electrical
equipment
1Check the operation of all instruments and
electrical equipment.
2Make sure that all instruments read
correctly, and switch on all electrical
equipment in turn, to check that it functions
properly.
Steering and suspension
3Check for any abnormalities in the steering,
suspension, handling or road “feel”.
4Drive the car, and check that there are no
unusual vibrations or noises.
5Check that the steering feels positive, with
no excessive “sloppiness”, or roughness, and
check for any suspension noises when
cornering and driving over bumps.
Drivetrain
6Check the performance of the engine and
transmission, listening for any unusual noises.7Make sure that the engine runs smoothly
when idling, and that there is no hesitation
when accelerating.
8Check that the gear changing action of the
transmission is smooth and progressive and
that the drive is taken up smoothly from a
standing start.
Braking system
9Make sure that the car does not pull to one
side when braking, and that the wheels do not
lock prematurely when braking hard.
10Check that there is no vibration through
the steering when braking.
11Check that the handbrake operates
correctly without excessive movement of the
lever, and that it holds the car stationary on a
slope.
12Test the operation of the brake servo unit
as follows. With the engine off, depress the
footbrake four or five times to exhaust the
vacuum. Hold the brake pedal depressed, then
start the engine. As the engine starts, there
should be a noticeable “give” in the brake
pedal as vacuum builds up. Allow the engine to
run for at least two minutes, and then switch it
off. If the brake pedal is depressed now, it
should be possible to detect a hiss from the
servo as the pedal is depressed. After about
four or five depressions, no further hissing
should be heard, and the pedal should feel
considerably harder.
1•14Every 7500 miles or 6 months
17.1 Detach the clips and separate the
cover, then slide the filter element out of
the housing
3261 Jaguar XJ6
14.6 Grease fittings for the rear
driveshafts are located in the centre
on each U-joint
Every 15 000 miles (24 000 km) or 12 months

Torque wrench settings*Nm lbf ft
Camshaft bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Camshaft sprocket bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Crankshaft damper-to-crankshaft bolt
3.2 and 3.6 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 151
4.0 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 to 220 133 to 162
Crankshaft pulley to damper bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Crankshaft rear oil seal retainer bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Crankshaft sensor bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Cylinder head bolts
Step 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 44
Step 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tighten an additional 90° (1/4 turn)
Driveplate bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 to 149 91 to 110
Engine mounts
To engine block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 to 66 36 to 39
To chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 24 16 to 18
Exhaust manifold heat shield fasteners . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Exhaust manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Intake manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Oil pump bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Sump bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Sump bolts, adapter to pan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 to 54 36 to 40
Timing chain cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Valve cover screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 to 12 7 to 9
*Note:Refer to Part B for additional specifications
2A•2 Engine in-car repair procedures
3261 Jaguar XJ6
1 General information
This Part of Chapter 2 is devoted to in-car
repair procedures for the in-line six-cylinder
engines. All information concerning engine
removal and refitting and engine block and
cylinder head overhaul can be found in Part B
of this Chapter.
The following repair procedures are based
on the assumption that the engine is installed
in the car. If the engine has been removed
from the car and mounted on a stand, many of
the steps outlined in this Part of Chapter 2 will
not apply. We have photographed some in-
car engine procedures with the engine on a
stand for photographic purposes.
The Specifications included in this Part of
Chapter 2 apply only to the procedures
contained in this Part. Part B of Chapter 2
includes the Specifications necessary for
cylinder head and engine block rebuilding.
2 Repair operations possible
with the engine in the car
Many repair operations can be
accomplished without removing the engine
from the car.
Clean the engine compartment and the
exterior of the engine with some type of
degreaser before any work is done. It will
make the job easier and help keep dirt out of
the internal areas of the engine.
Depending on the components involved, itmay be helpful to remove the bonnet to
improve access to the engine as repairs are
performed (refer to Chapter 11 if necessary).
Cover the wings to prevent damage to the
paint. Special pads are available, but an old
bedspread or blanket will also work.
If vacuum, exhaust, oil or coolant leaks
develop, indicating a need for gasket or seal
renewal, the repairs can generally be made
with the engine in the car. The intake and
exhaust manifold gaskets, crankshaft oil seals
and cylinder head gasket are all accessible
with the engine in place (although rear oil seal
renewal involves removal of the transmission).
The sump is difficult for a home mechanic to
replace without a hoist and other specialised
equipment, since the front suspension,
steering and crossmember must be lowered
to allow enough clearance for sump removal.
If such equipment is not available, the
alternative would be to remove the engine for
renewal of the sump or oil pump. Note:We
assume that the home mechanic does not
have access to the specialised equipment,
and have photographed our subject engine
out of the car for some procedures.
Exterior engine components, such as the
intake and exhaust manifolds, the water
pump, the starter motor, the alternator, the
distributor and the fuel system components
can be removed for repair with the engine in
place.
Since the cylinder head can be removed
with the engine in-car, camshaft and valve
component servicing can also be
accomplished. Renewal of the timing chains
and sprockets is also possible with the engine
in-car.
3 Top Dead Centre (TDC) for
number one piston- locating
1
Note:The following procedure is based on the
assumption that the distributor is correctly
installed. If you are trying to locate TDC to refit
the distributor correctly, piston position must
be determined by feeling for compression at
the number one spark plug hole, then aligning
the ignition timing marks (see paragraph 8).
1Top Dead Centre (TDC) is the highest point
in the cylinder that each piston reaches as it
travels up the cylinder bore. Each piston
reaches TDC on the compression stroke and
again on the exhaust stroke, but TDC
generally refers to piston position on the
compression stroke.
2Positioning the piston(s) at TDC is an
essential part of many procedures such as
camshaft and timing chain/sprocket removal
and distributor removal.
3Before beginning this procedure, be sure to
place the transmission in Neutral and apply
the handbrake or block the rear wheels. Also,
disable the ignition system by detaching the
coil wire from the centre terminal of the
distributor cap and grounding it on the engine
block with a jumper wire. Remove the spark
plugs (see Chapter 1).
4In order to bring any piston to TDC, the
crankshaft must be turned using one of the
methods outlined below. When looking at the
timing chain end of the engine, normal
crankshaft rotation is clockwise.
a) The preferred method is to turn the
crankshaft with a socket and ratchet

damage the crankshaft in the process (if the
crankshaft is damaged, the new seal will end
up leaking).
9The crankshaft seal rides on a spacer that
slips over the front of the crankshaft. Slip the
spacer off and clean the varnish off the seal
surface (see illustration).
10Clean the bore in the cover and coat the
outer edge of the new seal with engine oil or
multi-purpose grease. Apply moly-base
grease to the seal lip.
11Lubricate the spacer with clean engine oil
and refit it onto the crankshaft. Using a socket
with an outside diameter slightly smaller than
the outside diameter of the seal, carefully
drive the new seal into place with a hammer
(see illustration). Make sure it’s installed
squarely and driven in to the same depth as
the original. If a socket isn’t available, a short
section of large-diameter pipe will also work.
Note:The new seal comes with a plastic
installer guide. Do not remove this guide until
refitting is completed. The guide keeps the
seal lip properly oriented over the crankshaft.
12Refit the Woodruff key, then refit the
damper. Tighten the damper bolt to the
torque listed in this Chapter’s Specifications.
Note:The damper bolt can be used to pull the
damper back onto the crankshaft, but make
sure the damper is perfectly aligned with the
Woodruff key.
13The rest of the assembly is the reverse of
the removal procedure.
14Run the engine and check for oil leaks at
the front seal.
8 Timing chains
and sprockets- removal,
inspection and refitting
3
Caution: If the timing chain broke during
engine operation, the valves may have
come in contact with the pistons, causingdamage. Check the valve clearance (see
Section 10) before removal of the cylinder
head - bent valves usually will have
excessive clearance, indicating damage
that will require machine workshop work to
repair.
Note 1:This procedure requires that the sump
be removed (see Section 12).In a professional
workshop, this would be performed as an in-
car procedure with specialised tools to
remove the front suspension. Given the
equipment available to the average home
mechanic, this alternate procedure requires
removal of the engine from the car.
Note 2:If your engine is a 4.0 litre, built after
serial number 9J160552, and you’re
experiencing an engine rattle on cold starts
that disappears after the engine is warmed up,
the problem could be a defective upper
tensioner. A newly designed replacement
upper tensioner is available from the dealer
and should solve the problem. It can be
installed easily without pulling the cylinder
head or front cover, or can be installed during
a chain removal procedure.
Removal
1Disconnect the negative cable from 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.
2Block the rear wheels and set the
handbrake.
3Refer to Part B of this Chapter for engine
removal procedures.
4Refer to Section 4 and remove the valve
cover.
5Refer to Section 3 and position the engine
at TDC for cylinder number 1, then mark and
remove the distributor (see Chapter 5).
6Refer to Section 11 and remove the cylinder
head. After cylinder head removal, the uppertiming chain will be loosely retained by the
two upper chain guides, which are retained by
refitting a large rubber band (see Section 10).
Caution: Do not rotate the crankshaft with
the upper timing chain disconnected and
the cylinder head and camshafts in place,
or damage could result from piston-to-
valve contact.
7Some models may be equipped with a
hydraulic pump used for the brake
servo/hydraulic self-levelling suspension
system. If equipped, it will be mounted to the
front cover. Models not equipped with this
option will have a flat block-off plate over the
hole. If equipped with the pump, refer to
Chapters 9 and 10 for procedures to reduce
the high pressure in the brake servo system
and to depressurise the self-levelling system.
Before removing the engine, unbolt the pump
from the front cover and set it aside without
disconnecting the hoses (see illustration).
8Refer to Section 7 and remove the
crankshaft pulley and damper. Refer to
Section 12 for removal of the sump.
9If equipped with the hydraulic pump,
remove the coupling disc and unbolt the drive
coupling from the intermediate shaft (see
illustrations).
2A•6 Engine in-car repair procedures
8.7 Unbolt the hydraulic pump (arrowed)
from the front cover, without
disconnecting the hoses
3261 Jaguar XJ6 7.9 Remove the spacer from the end of the crankshaft
and clean it thoroughly
7.11 Drive the new seal squarely into the front cover with a large
socket or section of pipe - do not remove the plastic refitting
guide (arrowed) until the seal is installed

23Clean and lubricate the lower tensioner.
Fill the lower tensioner oil reservoir with engine
oil and refit it on the engine block, aligning the
notch in the tensioner with the lug on the back
of the guide (see illustrations). This should
remove all slack from the lower timing chain. If
not, push the lower tensioner guide back and
forth a few times to prime the tensioner.
24Refit the upper chain tensioner guide and
mounting bracket to the engine block.
Caution: Before fully tightening the
mounting bracket to the engine block,
make sure the mount and chain guide are
clear of the lower chain, auxiliary sprocket
and intermediate sprocket. If necessary,
position the mount for clearance before
tightening the mounting bolts.
25Refit the oil pump drive chain and
sprocket to the crankshaft (see Section 13).
26Refit the upper chain fixed guide to the
engine block and place the upper timing chain
over the intermediate sprocket and auxiliary
shaft sprocket, draping the excess chain over
the top of the fixed guide. Lubricate the chain
and sprockets with clean engine oil.27Gather the loose portion of the upper
timing chain and place it between the upper
guides. Use a large rubber band to hold the
two guides snugly around the chain (see
Section 11).
28If necessary, renew the intermediate shaft
seal (see illustrations).
29Apply a thin coat of RTV sealant to the
engine side of the front cover and RTV sealant
to the oil-pan mating surface (bottom of the
front cover), then refit the front cover. Note:
Make sure the top surface of the cover aligns
with the top surface of the engine block, by
checking with a straightedge(see illustration).
30Refer to Section 11 for refitting of the
cylinder head and Section 10 for refitting of
the camshafts and connection of the upper
timing chain to the two camshaft sprockets.
31The remainder of the refitting is the
reverse of the removal procedure. If your car
is equipped with the hydraulic/self-levelling
suspension, refit the drive coupling and
coupling disc to the intermediate shaft (see
illustrations 8.9a and 8.9b). Coat the
mounting surface of the pump with RTVsealant and make sure the tang on the pump
aligns with the slot in the intermediate shaft
before bolting the pump to the front cover.
Refer to Section 7 for refitting of the
crankshaft spacer, damper and puller.
Caution: DO NOT start the engine until
you’re absolutely certain that the timing
chains are installed correctly. Serious and
costly engine damage could occur if the
chains are installed wrong.
32Run the engine and check for proper
operation.
9 Auxiliary shaft- renewal
3
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.
1Refer to Chapter 10 and remove the power
steering pump, without disconnecting the
hoses. Remove the plastic power steering
pump drive coupling disc.
2A•8 Engine in-car repair procedures
8.28a Drill a small hole in the intermediate
shaft seal, thread a sheet metal screw into
it and use a small slide-hammer pull the
seal out of the cover8.28b Drive the new seal in with a seal-
driver or socket, to the same depth as the
original seal8.29 Bolt the front cover on hand tight, use
a straightedge to make sure the cover’s
top surface is level with the top of the
engine block, then tighten the cover bolts
3261 Jaguar XJ6 8.23a Add oil to the reservoir in the lower tensioner . . .
8.23b . . . and refit the tensioner against the guide -
after it’s installed, push the tensioner guide back and forth
a few times to prime the tensioner

21There are variations in cooling holes in
some models. Before refitting the cylinder
head gasket, carefully check all of the
passages and bolt holes in the new cylinder
head gasket to be sure it matches your engine
block. Also make sure the new cylinder head
gasket you’re using is equipped with the
improved oil transfer hole seal (see
illustration). Position the cylinder head gasket
over the dowel pins in the engine block, make
sure TOP is facing up (see illustration).
22Carefully place the cylinder head on the
engine block without disturbing the gasket.
23Refit NEW cylinder head bolts and
following the recommended sequence,
tighten the bolts in two steps to the torque
listed in this Chapter’s Specifications(see
illustration). Step 2 of the tightening
sequence requires the bolts to be tightened
and additional 90°. An angle-torque
attachment for your torque wrench is available
at car accessory outlets. This tool provides
precision when the angle-torque method is
required and its use is highly recommended. If
the tool is not available, paint a mark on the
edge of each cylinder head bolt and tighten
the bolt until the mark is 90¡ from the startingpoint. After the cylinder head bolts are
tightened, tighten the cylinder head-to-timing-
cover bolts.
24The remaining refitting steps are the
reverse of removal. Refer to Section 10 for
replacing the camshaft sprockets and
adjusting the timing chain and tensioner. Refill
the cooling system (see Chapter 1).
25Run the engine and check for oil or
coolant leaks. Adjust the ignition timing (see
Chapter 5) and road test the car.
12 Sump- removal and refitting
4
Removal
1 Note:The sump cannot be removed with
the engine in the chassis without lowering the
front suspension and crossmember. This is a
difficult procedure for the home mechanic
without a vehicle hoist and some other
specialised tools. The other alternative
requires the engine be removed from the car
and mounted on a stand, as we haveillustrated here. Refer to Part B of this Chapter
for engine removal procedures.
2Drain the engine oil and remove the oil filter
(see Chapter 1).
3Remove the bolts and detach the sump
(see illustration).
4If it’s stuck, pry it loose very carefully with a
small screwdriver or putty knife (see
illustration). Don’t damage the mating
surfaces of the pan and engine block or oil
leaks could develop.
2A•14 Engine in-car repair procedures
3261 Jaguar XJ6 11.21a Only use a head gasket with the improved oil transfer seal
(right arrow) - the older style (left arrow) is prone to oil leaks
11.21b Place the new head gasket over the dowels in the engine
block - note the markings for UP or TOP printed on the gasket
11.23 Cylinder head bolt TIGHTENING sequence12.3 Remove the sump bolts (arrowed)
12.4 Pry at the recess in the front of the
sump to break the gasket seal - insert a
putty knife, if necessary, between the
sump and engine block

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)

13Allow the bellcrank to return to the idle
position and test the adjustment once again
until the correct adjustment has been attained.
11 Electronic Fuel Injection
(EFI) system-
general information
1These models are equipped with an
Electronic Fuel Injection (EFI) system. This fuel
injection system is designed by Bosch butlicensed by Lucas and is called the Lucas LH
Engine Management system. The EFI system
is composed of three basic sub systems: fuel
system, air induction system and electronic
control system (see illustration).
Fuel system
2An electric fuel pump is located on the
chassis of the rear suspension (external) (1988
to 1990) or inside the fuel tank (1991 to 1994)
The fuel pump supplies fuel under constant
pressure to the fuel rail, which distributes fuel
evenly to all injectors. From the fuel rail, fuel is
injected into the intake ports, just above the
intake valves, by fuel injectors. The amount of
fuel supplied by the injectors is precisely
controlled by an Electronic Control Unit (ECU).
A pressure regulator controls system pressure
in relation to intake manifold vacuum. A fuel
filter between the fuel pump and the fuel rail
filters fuel to protect the components of the
system.
Air induction system
3The air system consists of an air filter
housing, a Mass Air Flow (MAF) sensor
(airflow meter), Intake Air Temperature (IAT)
sensor and a throttle body. The MAF sensor is
an information gathering device for the ECU.A heated element determines the temperature
differential by measuring the current changes
which in turn measures the mass (weight and
volume) of air entering the engine. This
information helps the ECU determine the
amount of fuel to be injected by the injectors.
The throttle plate inside the throttle body is
controlled by the driver. As the throttle plate
opens, the amount of air that can pass
through the system increases, so the
potentiometer opens further and the ECU
signals the injectors to increase the amount of
fuel delivered to the intake ports. Refer to
Chapter 6 for additional information on the
fuel injection system sensors, test procedures
and renewal procedures.
Electronic control system
4The Computer Control System controls the
EFI and other systems by means of an
Electronic Control Unit (ECU), which employs
a microcomputer. The ECU receives signals
from a number of information sensors which
monitor such variables as intake air volume,
intake air temperature, coolant temperature,
engine rpm, acceleration/deceleration and
exhaust oxygen content. These signals help
the ECU determine the injection duration
necessary for the optimum air/fuel ratio. Some
Fuel and exhaust systems 4•9
4
10.11 Rotate the bellcrank until it reaches
wide open throttle and make sure the
pointer aligns with the A on the bellcrank.
Adjust if necessary
11.1 Fuel injection and emission control component locations for the 3.6 litre 1989 XJ6
3261 Jaguar XJ6 1 Fuel pressure regulator (under
fuel rail)
2 Idle Speed Control (ISC) motor
3 Fuel pressure damper4 Bellcrank
5 Throttle body (below bellcrank)
6 Intake Air Temp. (IAT) sensor
7 Supplementary air valve8 Mass Airflow (MAF) sensor
9 Throttle potentiometer (under
throttle body)
10 Fuel rail11 Fuel injector
13 Ignition amplifier (below block
valve)
14 Distributor

6Be sure to buy new pads with wear
sensors. Pattern pads may not have wear
sensors; refitting pads without wear sensors
will cause the dash warning light to come on.
7To refit the new pads, reverse the removal
procedure. When refitting the caliper, be sure
to tighten the mounting bolts to the torque
listed in this Chapter’s Specifications.
8After the job is completed, depress the
brake pedal a few times to bring the pads into
contact with the discs. The pedal should be at
normal height above the floorpan and firm.
Check the brake fluid level and add enough to
top it up (see Chapter 1). Inspect carefully for
leaks and check the operation of the brakes
before placing the vehicle into normal service.
9Tighten the wheel nuts to the specified
torque.
4 Disc brake caliper- removal,
overhaul and refitting
3
Warning: Dust created by the
brake system may contain
asbestos, which is harmful to
your health. Never blow it out
with compressed air and don’t inhale any
of it. An approved filtering mask should be
worn when working on the brakes. Do not,
under any circumstances, use petroleum-
based solvents to clean brake parts. Use
brake system cleaner only!
Note 1:The following procedure applies to
both front and rear calipers.
Note 2:If an overhaul is indicated, explore all
options before beginning the job. New andfactory rebuilt calipers are available on an
exchange basis, which makes this job quite
easy. If you decide to rebuild the calipers,
make sure a rebuild kit is available before
proceeding. Always rebuild the calipers in
pairs - never rebuild just one of them.
Removal
1Loosen the wheel nuts, raise the front or
rear of the vehicle and place it securely on
axle stands. Remove the wheel.
2If you’re just removing the caliper for
access to other components, it isn’t
Braking system 9•3
9
3.5f Remove the outer brake pad3.5g Remove the inner brake pad
3.5h Pull out the wear sensor, trace the
sensor lead back to its plug, detach the
lead from the suspension, and discard it
3.5i Remove the caliper guide pins and
boots (lower pin and boot shown) . . .
3.5j . . . clean them off, inspect the pin and
boot for damage, renew as necessary,
then lubricate the pins with brake grease
and refit them in the caliper bracket
3.5k Apply anti-squeal compound to the
new brake pads
3261 Jaguar XJ6
3.5l Insert the new wear sensor into the
inner pad as shown . . .
3.5n Refit the outer pad
3.5m . . . then refit the inner pad onto the
caliper bracket
3.5o Refit the caliper, then tighten the
mounting bolts to the specified torque