ignition JAGUAR XJ 1994 2.G AJ16 Engine Manual

AJ16 Engine Service Manual
SERVICE DATA
Engine Data
Application Item
Number of cylinders
Bore
Specification
Seneral 6
91
mm
Stroke 3,2 liter: 83 mm
4,O liter: 102 mm
3.2 liter: 3239 cm3
4.0 liter: 3980 cm3
Cubic capacity
Compression ratio
3.2 liter: 1O:l
4,O liter: 1O:l (normally aspirated)
4,O liter: 8,51 (supercharged)
1,5,3,6,2,4 (No. 1 cylinder at
crankshaft pulley end)
Fully mapped Lucas engine
management system with digital
ignition
Firing
order
gnition timing
0
0
0
Jalve clearance
Intake and exhaust 0,30 to 0,36 mm
Champion RCSYCC (except North
America, normally aspirated
engines)
Champion
RC12YCC (North
America, for normally aspirated
engines only)
__ ~ ~
--__ ~~
Spark
plug
0,9 mm
On-plug ignition coil
Diamond
Number per vehicle
Primary winding resistance
Current consumption ~ ~~
6
0,75 ohm
Oto6A
Clockwise
(viewed from above)
1,5,3,6,2,4 (No. 1 cylinder at
crankshaft pulley end)
-
Engine position sensor
Fuel injection equipment
Exhaust Emission Rotation
Firing order
Micro
-processor controlled engine
management system
Fuel pressure
Exhaust gas analyzer reading (at
engine idle speed, normal operating
temperature and with catalytic
converter fitted)
3 bar
0,5% CO maximum.
For Swiss market only:
0,02% CO
maximum,
70 ppm HC maximum
Idle speed (engine at normal
operating temperature) Manual transmission 700 RPM
Automatic
transmission 700 RPM (gear selector in neutral)
11,O to 11,7 bar (with all spark plugs
removed, throttle fully open, engine
at operating temperature and
a
minimum cranking speed of 300
RPM)
0,7 bar (maximum)
Compression pressure
Cylinder pressure
Differential pressure between
cylinders
Aluminum alloy
Cylinder block
. ___ Material
xiii
Issue 1 August 1994

AJ16 Engine Service Manual
FAULT DIAGNOSIS
3.1 Introduction
The following diagnostic procedures are provided to assist properly qualified persons to identify and rectify the faults
relating to the engine which are most likely to encountered. Reference is made to the Electrical Diagnostic Manual
(EDM), which should be consulted where necessary. Faults related to the cooling system are dealt with in Section 4.1
and to the fuel system in Section 5.1 in the appropriate Vehicle Service Manual (VSM).
3.2 Diagnostic Procedures
(fails to rotate)
I Engine rotates but 0 I will not fire
I
i
/Overheating
Overheating at tick-
Too cold
Loss of coolant Possible
Cause
Battery leads loose or ter
- minals corroded
Battery discharged
Starter motor inoperative
Starter motor speed too
low
Faulty ignition system
Fuel system defect
Oil requires changing
Worn crankshaft journals
Excessive crankshaft
end- float
Worn main bearing shells
Worn oil pump Oil pressure relief valve stick
- ing open
Oil pressure relief valve
spring too weak
Insufficient oil in oil pan
Engine overheating
Faulty gauge or sensor
Incorrect grade oil (viscosity
too low)
Water in oil Check
Check the condition of the
leads and terminals
Check condition of battery
with hydrometer
If the lights dim when ignition
switch is operated, the starter
may be jammed in starter
ring.
Check for loose and dirty con
- nections to the starter motor
Check battery leads and ter
- minals
Check state of battery charge
Refer to EDM
Remove the spark plugs
Check oil level and color
Listen for rumble or knock
Fit dial gauge and measure
Listen for rumble
Remove oil pump and check
the clearances
Remove valve and check for
sticking
Remove spring and check
spring rates
Check oil level
Refer to EDM
Check oil viscosity
Checkoil level and check if oil
is a milky white color
Check for leaking head gasket Remedy
Clean and tighten as necess
-
ary
Charge or renew battery as
necessary
Remove starter motor, free
off pinion and refit
Clean and tighten connec
- tions
Clean and tighten terminals
Charge or renew battery
as necessary
Rectify as required
Clean and re
-gap the spark
plugs, renew if worn out
Refer to Fuel System fault
finding in Section
5.1, VSM
Refer to Section
4.1, VSM
Refer to Section
4.1, VSM
Refer to Section
4.1, VSM
Refer to Section
4.1, VSM
Change oil and filter
Renew crankshaft
Renew thrust washers
Check crankshaft journals for
wear and renew shells
Renew oil pump
Renew valve
Renew spring
lop-up as required
Refer to Overheating fault
finding in Section
4.1, VSM
Rectify as required
Renew oil and filter
Renew oil and filter
Renew head gasket
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AJ16 Engine Service Manual
Symptom
Joisy chains
)etonation knock pinking)
.oss of power
Gugh running at iormal engine speed Possible
Cause
Low oil pressure
Tensioners not released
Chains worn
Sprockets worn
Tensioner worn
Ignition timing too far ad
- vanced
Head gasket leaking
Fuel
/ air mixture too weak
Engine running
too hot
Valve timing incorrect
Incorrect grade fuel
Burned valves Sticking valves
Poor engine tune
Insufficient valve clearance
Fuel injection fault
Lowcompression in cylinders
Ignition fault
Valve timing incorrect
Partial seizure of engine
Worn
camshaftb)
Incorrect grade fuel
Sticking valves Broken valve springs Piston fault
Leaking head gasket
Valve burned out
Valve seat burned out
Ignition fault
Fuel injection fault
Check
Take reading from oil pres- sure gauge when engine is
hot
Remove camshaft cover and
check tension of chain (top
chain). Remove timing cover
to check bottom chain tension
Visually check
/ remove and
check for wear
Visual check
Visual check
Refer to EDM
Check engine oil level and
checkfor contamination of oil
Pressure test cooling system
and check for contamination
of coolant in header tank
Refer to EDM
Check valve timing
If all other checks
OK, this
could be the cause
Check cylinder compressions
Check cylinder compressions
Refer to EDM
Check valve clearance
Check compressions
Refer to EDM
Check valve timing
Remove spark plugs and ro
- tate crankshaft
Remove
camshaft(s) and
check for wear
If all other checks OK this
could be the cause
Check cylinder compressions
Check cylinder compressions
and for bent valve stems
Check cylinder cornpressions
Check cylinder compressions
Check cylinder compressions
Refer to
EDM
Remedy
Refer to Insufficient Oil Pres- sure fault finding
Insert
3 mm Allen key and
turn tensioner anti-clock- wise, compress tensioner to
release bottom chain
Renew as necessary
Renew as necessary
Renew as necessary
Rectify as required
Renew head gasket
Rectify
as required
Refer
to Overheating fault
finding in Section 4.1, VSM
Adjust valve timing
Drain fuel tank and refill with
correct grade fuel
Remove cylinder head and
renew valves
Remove cylinder head and
renew valves
/ guides or
springs
Rectify as required
Adjust as necessary
Refer to Fuel System fault
finding in Section 5.1, VSM
Rebore
1 re-ring as necessary
Rectify as required
Adjust valve timing
Overhaul engine as required
Renew
camshaft(s)
Drain fuel tank and refill with
correct grade fuel
Renew valve, springs or
guides
Renew valve springs and
valves as required
Renew pistons
Refer to Detonation Knock
fault finding
Renew valve
Re
-cut or renew valve seat
Rectify as required
Refer to Fuel System fault
Tindim in Section 5.1, VSM
issue 1 August 1994 5

AJ16 Engine Service Manual
Symptom
3ough running at iormal engine speed
continued)
3ough idle
Engine backfires
Engine spits back
nto
air box
Engine fails to idle
Possible Cause
Air leaking into intake mani- fold
Leaking exhaust
Valve timing incorrect
Incorrect ignition timing
Valve burned out
Ignition fault
Fuel injection fault
Air leakage
intolfrom the ex- haust system
Leakage past valves and
guides
Ignition timing retarded
Incorrect valve timing
Valves not closing properly
Excessively weak mixture
Air leaking into intake mani
- fold
Incorrect ignition timing
Valve clearances insufficient
Cylinder head gasket leaking
Blockage in exhaust system
Check
Run engine and check for
leaks / whistling. Spray 'Easy Start' around suspect area
[the engine speed will in- crease if an air leak is present)
Visual check
Check valve timing
Refer to EDM
Check cylinder compressions
Refer to EDM
Checkfor leaksor blows in the
system
Check for crankcase fumes
and refer to EDM for analysis
of exhaust gases
Refer to EDM
Check valve timing
Check valve clearances
Check for wear or gum in
valve guides
Check for poor seating of
valves
Refer to EDM
Run engine and check for
leaks
/ whistling. Spray 'Easy
Start' around suspect area
(the engine speed will in- crease if an air leak is present)
Refer to EDM
Check clearances
Check for restrictions
Remedy
Renew gasket or manifold
Repair leak or renew exhaust
Adjust valve timing
Rectify as required
Renew valve
Rectify as required
Refer to Fuel System fault
finding in Section
5.1, VSM
Repair leaks or renew system if necessary
Remove the cylinder head
and overhaul
Rectify as required
Adjust valve timing
Adjust valve clearances
Renew guides or decarbonize
the cylinder head
Overhaul the cylinder head
Rectify as required
Renew intake tube
or gasket
Rectify as required
Adjust clearances
Refer to Detonation Knock
fault finding
Remove the restrictions or
renew components as
necessary
Issue 1 August 1994 6