1997 JAGUAR XJ6 fuel consumption

Engine block
Deck warpage limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.076 mm (0.003 inch)
Cylinder bore diameter
Standard
Size group A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90.990 to 91.003 mm (3.5823 to 3.5828 inches)
Size group B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.005 to 91.018 mm (3.5829 to 3.5834 inches)
Oversize
0.25 mm (0.010 inch) OS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.259 to 91.272 mm (3.5929 to 3.5934 inches)
0.50 mm (0.020 inch) OS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.513 to 91.526 mm (3.6029 to 3.6034 inches)
Pistons and rings
Piston-to-bore clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.017 to 0.043 mm (0.0007 to 0.0017 inch)
Piston ring end gap
No.1 (top) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.66 mm (0.016 to 0.026 inch)
No.2 (middle) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.66 mm (0.016 to 0.026 inch)
Oil ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.55 mm (0.012 to 0.022 inch)
Piston ring groove clearance
No. 1 (top) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.076 mm (0.0016 to 0.0030 inch)
No. 2 (middle) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.076 mm (0.0016 to 0.0030 inch)
Torque wrench settingsNm lbf ft
Main bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 to 142 100 to 105
Connecting rod cap nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 to 60 37 to 44
* Note:Refer to Part A for additional torque specifications.
2B•2 Engine removal and overhaul procedures
3261 Jaguar XJ6
1 General information
Included in this portion of Chapter 2 are the
general overhaul procedures for the cylinder
head and internal engine components.
The information ranges from advice
concerning preparation for an overhaul and
the purchase of replacement parts to detailed,
step-by-step procedures covering removal
and refitting of internal engine components
and the inspection of parts.
The following Sections have been written
based on the assumption that the engine has
been removed from the vehicle. For
information concerning in-vehicle engine
repair, as well as removal and refitting of the
external components necessary for the
overhaul, see Part A of this Chapter.
The Specifications included in this Part are
only those necessary for the inspection and
overhaul procedures which follow. Refer to
Part A for additional Specifications.
2 Engine overhaul-
general information
It’s not always easy to determine when, or if,
an engine should be completely overhauled,
as a number of factors must be considered.
High mileage is not necessarily an indication
that an overhaul is needed, while low mileage
doesn’t preclude the need for an overhaul.
Frequency of servicing is probably the most
important consideration. An engine that’s had
regular and frequent oil and filter changes, as
well as other required maintenance, will most
likely give many thousands of miles of reliableservice. Conversely, a neglected engine may
require an overhaul very early in its life.
Excessive oil consumption is an indication
that piston rings, valve seals and/or valve
guides are in need of attention. Make sure that
oil leaks aren’t responsible before deciding
that the rings and/or guides are bad. Perform a
cylinder compression check to determine the
extent of the work required (see Section 4).
Also check the vacuum readings under various
conditions (see Section 3).
Check the oil pressure with a gauge
installed in place of the oil pressure sender
unit (see illustrations)and compare it to this
Chapter’s Specifications. If it’s extremely low,
the bearings and/or oil pump are probably
worn out.
Loss of power, rough running, knocking or
metallic engine noises, excessive valve train
noise and high fuel consumption rates may
also point to the need for an overhaul,
especially if they’re all present at the same
time. If a complete tune-up doesn’t remedy
the situation, major mechanical work is the
only solution.An engine overhaul involves restoring the
internal parts to the specifications of a new
engine. During an overhaul, the piston rings
are replaced and the cylinder walls are
reconditioned (rebored and/or honed). If a
rebore is done by an automotive machine
workshop, new oversize pistons will also be
installed. The main bearings, big-end bearings
and camshaft bearings are generally replaced
with new ones and, if necessary, the
crankshaft may be reground to restore the
journals. Generally, the valves are serviced as
well, since they’re usually in less-than-perfect
condition at this point. While the engine is
being overhauled, other components, such as
the distributor, starter and alternator, can be
rebuilt as well. The end result should be a like
new engine that will give many trouble free
miles. Note:Critical cooling system
components such as the hoses, drivebelts,
thermostat and water pump should be
replaced with new parts when an engine is
overhauled. The radiator should be checked
carefully to ensure that it isn’t clogged or
leaking (see Chapter 3).If you purchase a
2.4a The oil pressure sender unit (arrowed)
is located in the right front corner of the
engine block, near the oil filter2.4b The oil pressure can be checked by
removing the sender unit and refitting a
pressure gauge in its place

3261 Jaguar XJ6
REF•2Conversion factors
Length (distance)
Inches (in) x 25.4 = Millimetres (mm) x 0.0394 = Inches (in)
Feet (ft) x 0.305 = Metres (m) x 3.281 = Feet (ft)
Miles x 1.609 = Kilometres (km) x 0.621 = Miles
Volume (capacity)
Cubic inches (cu in; in3) x 16.387 = Cubic centimetres (cc; cm3) x 0.061 = Cubic inches (cu in; in3)
Imperial pints (Imp pt) x 0.568 = Litres (l) x 1.76 = Imperial pints (Imp pt)
Imperial quarts (Imp qt) x 1.137 = Litres (l) x 0.88 = Imperial quarts (Imp qt)
Imperial quarts (Imp qt) x 1.201 = US quarts (US qt) x 0.833 = Imperial quarts (Imp qt)
US quarts (US qt) x 0.946 = Litres (l) x 1.057 = US quarts (US qt)
Imperial gallons (Imp gal) x 4.546 = Litres (l) x 0.22 = Imperial gallons (Imp gal)
Imperial gallons (Imp gal) x 1.201 = US gallons (US gal) x 0.833 = Imperial gallons (Imp gal)
US gallons (US gal) x 3.785 = Litres (l) x 0.264 = US gallons (US gal)
Mass (weight)
Ounces (oz) x 28.35 = Grams (g) x 0.035 = Ounces (oz)
Pounds (lb) x 0.454 = Kilograms (kg) x 2.205 = Pounds (lb)
Force
Ounces-force (ozf; oz) x 0.278 = Newtons (N) x 3.6 = Ounces-force (ozf; oz)
Pounds-force (lbf; lb) x 4.448 = Newtons (N) x 0.225 = Pounds-force (lbf; lb)
Newtons (N) x 0.1 = Kilograms-force (kgf; kg) x 9.81 = Newtons (N)
Pressure
Pounds-force per square inch x 0.070 = Kilograms-force per square x 14.223 = Pounds-force per square inch
(psi; lbf/in2; lb/in2) centimetre (kgf/cm2; kg/cm2) (psi; lbf/in2; lb/in2)
Pounds-force per square inch x 0.068 = Atmospheres (atm) x 14.696 = Pounds-force per square inch
(psi; lbf/in
2; lb/in2)(psi; lbf/in2; lb/in2)
Pounds-force per square inch x 0.069 = Bars x 14.5 = Pounds-force per square inch
(psi; lbf/in
2; lb/in2)(psi; lbf/in2; lb/in2)
Pounds-force per square inch x 6.895 = Kilopascals (kPa) x 0.145 = Pounds-force per square inch
(psi; lbf/in
2; lb/in2)(psi; lbf/in2; lb/in2)
Kilopascals (kPa) x 0.01 = Kilograms-force per square x 98.1 = Kilopascals (kPa)
centimetre (kgf/cm
2; kg/cm2)
Millibar (mbar) x 100 = Pascals (Pa) x 0.01 = Millibar (mbar)
Millibar (mbar) x 0.0145 = Pounds-force per square inch x 68.947 = Millibar (mbar)
(psi; lbf/in
2; lb/in2)
Millibar (mbar) x 0.75 = Millimetres of mercury (mmHg) x 1.333 = Millibar (mbar)
Millibar (mbar) x 0.401 = Inches of water (inH
2O) x 2.491 = Millibar (mbar)
Millimetres of mercury (mmHg) x 0.535 = Inches of water (inH
2O) x 1.868 = Millimetres of mercury (mmHg)
Inches of water (inH
2O) x 0.036 = Pounds-force per square inch x 27.68 = Inches of water (inH2O)
(psi; lbf/in2; lb/in2)
Torque (moment of force)
Pounds-force inches x 1.152 = Kilograms-force centimetre x 0.868 = Pounds-force inches
(lbf in; lb in) (kgf cm; kg cm) (lbf in; lb in)
Pounds-force inches x 0.113 = Newton metres (Nm) x 8.85 = Pounds-force inches
(lbf in; lb in)(lbf in; lb in)
Pounds-force inches x 0.083 = Pounds-force feet (lbf ft; lb ft) x 12 = Pounds-force inches
(lbf in; lb in)(lbf in; lb in)
Pounds-force feet (lbf ft; lb ft) x 0.138 = Kilograms-force metres x 7.233 = Pounds-force feet (lbf ft; lb ft)
(kgf m; kg m)
Pounds-force feet (lbf ft; lb ft) x 1.356 = Newton metres (Nm) x 0.738 = Pounds-force feet (lbf ft; lb ft)
Newton metres (Nm) x 0.102 = Kilograms-force metres x 9.804 = Newton metres (Nm)
(kgf m; kg m)
Power
Horsepower (hp) x 745.7 = Watts (W) x 0.0013 = Horsepower (hp)
Velocity (speed)
Miles per hour (miles/hr; mph) x 1.609 = Kilometres per hour (km/hr; kph) x 0.621 = Miles per hour (miles/hr; mph)
Fuel consumption*
Miles per gallon (mpg) x 0.354 = Kilometres per litre (km/l) x 2.825 = Miles per gallon (mpg)
Temperature
Degrees Fahrenheit = (°C x 1.8) + 32 Degrees Celsius (Degrees Centigrade; °C) = (°F - 32) x 0.56
* It is common practice to convert from miles per gallon (mpg) to litres/100 kilometres (l/100km), where mpg x l/100 km = 282

3261 Jaguar XJ6
REF•12Fault finding
Introduction
This Section provides an easy reference guide to the more common
problems which may occur during the operation of your vehicle. These
problems and their possible causes are grouped under headings
denoting various components or systems, such as Engine, Cooling
system, etc. They also refer you to the Chapter and/or Section which
deals with the problem.
Remember that successful troubleshooting is not a mysterious
“black art” practised only by professional mechanics. It is simply the
result of the right knowledge combined with an intelligent, systematic
approach to the problem. Always work by a process of elimination,
starting with the simplest solution and working through to the mostcomplex - and never overlook the obvious. Anyone can run the petrol
tank dry or leave the lights on overnight, so don’t assume that you are
exempt from such oversights.
Finally, always establish a clear idea of why a problem has occurred
and take steps to ensure that it doesn’t happen again. If the electrical
system fails because of a poor connection, check all other connections
in the system to make sure that they don’t fail as well. If a particular
fuse continues to blow, find out why - don’t just replace one fuse after
another. Remember, failure of a small component can often be
indicative of potential failure or incorrect functioning of a more
important component or system.
Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
m mEngine backfires
m mEngine diesels (continues to run) after switching off
m mEngine hard to start when cold
m mEngine hard to start when hot
m mEngine lacks power
m mEngine lopes while idling or idles erratically
m mEngine misses at idle speed
m mEngine misses throughout driving speed range
m mEngine rattles at start-up
m mEngine rotates but will not start
m mEngine runs with oil pressure light on
m mEngine stalls
m mEngine starts but stops immediately
m mEngine stumbles on acceleration
m mEngine surges while holding accelerator steady
m mEngine will not rotate when attempting to start1
m mOil puddle under engine
m mPinking or knocking engine sounds during acceleration or uphill
m mStarter motor noisy or excessively rough in engagement
Fuel system . . . . . . . . . . . . . . . . . . . . . . . . .2
m
mExcessive fuel consumption
m mFuel leakage and/or fuel odour
Cooling system . . . . . . . . . . . . . . . . . . . . . .3
m
mCoolant loss
m mExternal coolant leakage
m mInternal coolant leakage
m mOvercooling
m mOverheating
m mPoor coolant circulation
Automatic transmission . . . . . . . . . . . . . . .4
m
mEngine will start in gears other than Park or Neutral
m mFluid leakage
m mShift cable problems
m mTransmission fluid brown or has a burned smell
m mTransmission slips, shifts roughly, is noisy or has no drive
m min forward or reverse gears
m mTransmission will not downshift with accelerator pedal
pressed to the floor
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
m mBrake pedal feels spongy when depressed
m mBrake pedal travels to the floor with little resistance
m mBrake roughness or chatter (pedal pulsates)
m mDragging brakes
m mExcessive brake pedal travel
m mExcessive pedal effort required to stop vehicle
m mGrabbing or uneven braking action
m mNoise (high-pitched squeal when the brakes are applied)
m mHandbrake does not hold
m mVehicle pulls to one side during braking
Suspension and steering systems . . . . . . .6
m
mAbnormal noise at the front end
m mAbnormal or excessive tyre wear
m mCupped tyres
m mErratic steering when braking
m mExcessive pitching and/or rolling around corners or
during braking
m mExcessive play or looseness in steering system
m mExcessive tyre wear on inside edge
m mExcessive tyre wear on outside edge
m mHard steering
m mPoor returnability of steering to centre
m mRattling or clicking noise in rack-and-pinion
m mShimmy, shake or vibration
m mSuspension bottoms
m mTyre tread worn in one place
m mVehicle pulls to one side
m mWander or poor steering stability
m mWheel makes a “thumping” noise
Electrical system . . . . . . . . . . . . . . . . . . . . .7
Battery will not hold a charge
Discharge warning light fails to come on when key is turned on
Discharge warning light fails to go out

3261 Jaguar XJ6
REF•14Fault finding
2 Fuel system
Engine surges while holding accelerator steady
m mIntake air leak (Chapter 4).
m mFuel pump faulty (Chapter 4).
m mLoose fuel injector harness connections (Chapters 4 and 6).
m mDefective ECU (Chapter 6).
Pinking or knocking engine sounds during
acceleration or uphill
m mIncorrect grade of fuel.
m mDistributor installed incorrectly (Chapter 5).
m mFuel injection system in need of adjustment (Chapter 4).
m mImproper or damaged spark plugs or wires (Chapter 1).
m mWorn or damaged distributor components (Chapter 5).
m mFaulty emission system (Chapter 6).
m mVacuum leak (Chapter 4).
m mFuel rail feed (inlet) hose has hardened, resulting in knocking noise
near dash (see Chapter 4).
Engine lacks power
m mIncorrect ignition timing (Chapter 5).
m mExcessive play in distributor shaft (Chapter 5).
m mWorn rotor, distributor cap or wires (Chapters 1 and 5).
m mFaulty or incorrectly gapped spark plugs (Chapter 1).
m mFuel injection system malfunctioning (Chapter 4).
m mFaulty coil (Chapter 5).
m mBrakes binding (Chapter 1).
m mAutomatic transmission fluid level incorrect (Chapter 1).
m mFuel filter clogged and/or impurities in the fuel system (Chapter 1).
m mEmission control system not functioning properly (Chapter 6).
m mLow or uneven cylinder compression pressures (Chapter 2).
Engine rattles at start-up
m
mFailure of upper timing chain tensioner (Chapter 2).
Engine backfires
m
mEmissions system not functioning properly (Chapter 6).
m mIgnition timing incorrect (Chapter 1).
m mFaulty secondary ignition system (cracked spark plug insulator,
faulty plug leads, distributor cap and/or rotor) (Chapters 1 and 5).
m mFuel injection system malfunctioning (Chapter 4).
m mVacuum leak at fuel injector(s), intake manifold or vacuum hoses
(Chapter 4).
Engine stalls
m mIdle speed incorrect (Chapter 1).
m mFuel filter clogged and/or water and impurities in the fuel system
(Chapter 1).
m mDistributor components damp or damaged (Chapter 5).
m mFaulty emissions system components (Chapter 6).
m mFaulty or incorrectly gapped spark plugs (Chapter 1).
m mFaulty spark plug leads (Chapter 1).
m mVacuum leak in the fuel injection system, intake manifold or
vacuum hoses (Chapter 4).
Engine runs with oil pressure light on
m mLow oil level (Chapter 1).
m mIdle rpm too low (Chapter 1).
m mShort in wiring circuit (Chapter 12).
m mFaulty oil pressure sending unit (Chapter 2).
m mWorn engine bearings and/or oil pump (Chapter 2).
Engine diesels (continues to run)
after switching off
m mIdle speed too high (Chapter 4).
m mExcessive engine operating temperature (Chapter 3).
m mIncorrect fuel octane grade.
Excessive fuel consumption
m
mDirty or clogged air filter element (Chapter 1).
m mIncorrectly set ignition timing (Chapter 5).
m mEmissions system not functioning properly (Chapter 6).
m mFuel injection internal parts worn or damaged (Chapter 4).
m mLow tyre pressure or incorrect tyre size (Chapter 1).
Fuel leakage and/or fuel odour
m
mLeak in a fuel feed or vent line (Chapter 4).
m mTank overfilled.
m mFuel injector internal parts excessively worn (Chapter 4).
3 Cooling system
Overheating
m
mInsufficient coolant in system (Chapter 1).
m mWater pump drivebelt defective or out of adjustment (Chapter 1).
m mRadiator core blocked or grille restricted (Chapter 3).
m mThermostat faulty (Chapter 3).
m mRadiator cap not maintaining proper pressure (Chapter 3).
m mIgnition timing incorrect (Chapter 5).
Overcooling
m
mFaulty thermostat (Chapter 3).
External coolant leakage
m
mDeteriorated/damaged hoses; loose clamps (Chapters 1 and 3).
m mWater pump seal defective (Chapters 1 and 3).
m mLeakage from radiator core or manifold tank (Chapter 3).
m mEngine drain or water jacket core plugs leaking (Chapter 2).
m mHoses behind water pump leaking (Chapter 3).
Internal coolant leakage
m
mLeaking cylinder head gasket (Chapter 2).
m mCracked cylinder bore or cylinder head (Chapter 2).
Coolant loss
m
mToo much coolant in system (Chapter 1).
m mCoolant boiling away because of overheating (Chapter 3).
m mInternal or external leakage (Chapter 3).
m mFaulty radiator cap (Chapter 3).
Poor coolant circulation
m
mInoperative water pump (Chapter 3).
m mRestriction in cooling system (Chapters 1 and 3).
m mWater pump drivebelt defective/out of adjustment (Chapter 1).
m mThermostat sticking (Chapter 3).
1 Engine (continued)