1994 JEEP CHEROKEE Starter

Wiring Diagram Name Sheet Number
License Lamp...........................91,95
Low Washer Indicator Lamp..................57,58
Malfunction Indicator Lamp..................57,58
Maintenance Required Indicator Lamp...........57,58
Park Brake Indicator Lamp.....................58
Reading Lamp.............................51
Rear Wiper/Wash Switch Lamp..................47
Right Back-Up Lamp.......................92,96
Right Courtesy Lamp........................49
Right Fog Lamp............................40
Right Headlamp............................40
Right Park/Turn Signal Lamp...................40
Right Side Marker Lamp (Front).................40
Right Side Marker (Rear)....................92,96
Right Tail/Stop Lamp......................92,96
Right Turn Indicator Lamp.................59,60,61
Right Turn Lamp (Amber)...................92,96
Right Vanity Lamp..........................51
Seat Belt Warning Indicator Lamp..............57,58
Transfer Case Lamp.........................48
Transmission Range Switch Lamp................48
Underhood Lamp...........................34
Upshift Indicator Lamp.....................57,58
Vanity Lamps...........................51,53
L.C.D. Illumination Relay........................52
Left Front Door Connector And Door Lock Switch
Function Chart.............................87
Left Front Door Connector and Widow Lift Switch
Function Chart.............................87
Left Front Door Jamb Switch.....................75
Left Front Door Lock Motor......................86
Left Front Door Speaker........................71
Left Front Wheel Sensor........................29
Left Instrument Panel Speaker....................71
Left Liftgate Speaker..........................72
Left Power Seat Motor Assembly..................77
Left Power Seat Switch........................77
Left Rear Door Connector and Window Lift Switch
Function Chart.............................88
Left Rear Door Jamb Switch.....................75
Left Rear Door Window Switch...................82
Left Rear Wheel Sensor........................29
Left Turn Relay..............................97
Liftgate Switch..............................76
Liftgate Lock motor...........................86
Lo-Line Instrument Cluster Printed Circuit Board........60
Low Fuel Warning Module...................59,60,61
Low Washer Indicator Lamp...................57,58
Main Body Connectors........................112
Maintenance Required Indicator Lamp.............57,58
Malfunction Indicator Lamp....................57,58
Map Sensor..............................14,19
Modules
Anti-Lock Brake System Module.........29,30,31,32,33
Chime Module.............................74
Daytime Running Lamp Module.................38
Headlamp Delay Module......................43
Intermittent Wiper Module.....................64Wiring Diagram Name Sheet Number
Low Fuel Warning Module.................59,60,61
Powertrain Control Module. . . .11,12,13,14,15,16,17, 18,19,
20,21,22,23,35,36,45,55,69
Remote Keyless Entry Module...................28
Transmission Control Module.................25,26
Motors
ABS Pump Motor...........................30
A/C Heater Blower Motor......................70
Engine Starter Motor........................7,8
Front Wiper Motor........................63,64
Heater Blower Motor.........................68
Idle Air Control Motor......................15,22
Left Front Door Lock Motor....................86
Left Front Door Window Motor..................81
Left Power Mirror..........................73
Left Power Seat Motor Assembly................77
Left Rear Door Lock Motor....................86
Left Rear Door Window Motor..................82
Liftgate Lock Motor.........................86
Radiator Fan Motor.........................23
Rear Wiper Motor..........................65
Right Front Door Lock Motor...................86
Right Front Door Window Motor.................81
Right Power Mirror.........................73
Right Rear Door Lock Motor...................86
Right Rear Door Window Motor.................82
Oil Pressure Switch...........................24
Overhead Console System.....................53,54
Ambient Temperature Sensor...................53
Overhead Console..........................53
Vanity Lamps.............................53
Park Brake Switch............................67
Park Brake Indicator Lamp......................58
Parking Brake Switch..........................67
Park Lamp Relay.............................39
Park/Neutral Position Switch......................7
Pedal Travel Sensor...........................30
Power Distribution Center....................1,2,3,4
Power Distribution Center Application Chart............4
Power Distribution Center Identification...............3
Power Door Locks......................83,84,85,86
Left Door Lock Switch.......................85
Left Front Door Lock Motor....................86
Left Rear Door Lock Motor....................86
Liftgate Lock Motor.........................86
Power Door Lock Relay.......................83
Power Door Unlock Relay.....................83
Right Door Lock Switch......................85
Right Front Door Lock Motor...................86
Right Rear Door Lock Motor...................86
Power Door Lock Relay........................83
Power Door Unlock Relay.......................83
Power Mirror Connector.......................110
Power Mirror Connector and Switch Function Chart......88
Power Mirror Switch Assembly...................73
Power Mirror System..........................73
Left Power Mirror..........................73
Power Mirror Switch Assembly..................73
8W - 152 WIRING DIAGRAMSJ

Wiring Diagram Name Sheet Number
Right Power Mirror.........................73
Power Mirrors.............................73
Power Seat..............................77,78
Left Power Seat Motor Assembly................77
Left Power Seat Switch.......................78
Power Steering Pressure Switch...................15
Powertrain Control Module......11,12,13,14,15,16,17,18,19,
20,21,22,23,35,36,45,55,69
Powertrain Control Module (PCM) Connector..........111
Power Windows.......................79,80,81,82
Left Front Door Window Motor..................81
Left Rear Door Window Motor..................82
Left Rear Door Window Switch..................82
Power Window Switch.......................79
Right Front Door Window Switch................81
Right Front Door Window Motor.................81
Right Rear Door Window Motor.................82
Right Rear Door Window Switch.................82
Power Window Switch.........................79
Printed Circuit Boards.................57,58,59,60,61
Pumps
Front Washer...........................63,64
Rear Washer..............................65
Radiator Fan Motor...........................23
Radio....................................71
Antenna Mast.............................71
Left Front Door Speaker......................71
Left Instrument Panel Speaker..................71
Left Liftgate Speaker.........................72
Right Front Door Speaker.....................72
Right Instrument Panel Speaker.................72
Right Liftgate Speaker........................72
Reading Lamps..............................51
Rear Lighting...................91,92,93,94,95,96,97
Left Back-Up Lamp........................91,93
Left Side Marker Lamp (Rear)................91,93
Left Tail/Stop Lamp.......................91,93
Left Turn Lamp (Amber)....................91,93
Left Turn Relay............................97
License Lamp...........................91,95
Right Back-Up Lamp.......................92,96
Right Side Marker Lamp (Rear)...............92,96
Right Tail/Stop Lamp......................92,96
Right Turn Lamp (Amber)...................92,96
Right Turn Relay...........................97
Stop Lamp Relay...........................97
Trailer Tow Connector........................93
Trailer Tow In-Line Circuit Breaker................97
Rear Lighting With Trailer Tow............93,94,95,96,97
Rear Lighting Without Trailer Tow................91,92
Rear Washer Pump...........................65
Rear Wiper Motor............................65
Rear Wiper/Washer Motor.......................65
Rear Washer Pump...........................65
Rear Wiper Motor............................65
Rear Wiper/Washer Switch......................65
Rear Wiper/Washer Switch Lamp..................47
Reed Switch................................26Wiring Diagram Name Sheet Number
Relays
ABS #1 Relay............................3,31
ABS #2 Relay............................3,31
A/C Compressor Clutch Relay..................3,69
Automatic Shut Down Relay.................3,12,17
Cooling Fan Relay...........................3
EMCC Relay.............................3,27
Engine Starter Relay.......................3,7,8
Fan Control Relay...........................23
Fuel Pump Relay........................3,12,17
Heated Rear Window Relay....................66
High Beam Relay...........................40
Horn Relay...............................34
L.C.D. Illumination Relay......................52
Left Turn Relay............................97
Park Lamp Relay...........................39
Power Door Lock Relay.......................83
Power Door Unlock Relay.....................83
Right Turn Relay...........................97
Stop Lamp Relay...........................97
Relay Center Identification......................113
Remote Keyless Entry System....................28
Remote Keyless Entry Module...................28
Remote Keyless Entry Module Connector...........114
Resistor,Ballast..............................39
Resistor,Blower..............................68
Right Front Door Jamb Switch....................76
Right Front Door Speaker.......................72
Right Front Door Window Switch..................81
Right Front Wheel Sensor.......................29
Right Front Door Connector and Door Lock Switch
Function Chart.............................87
Right Front Door Lock Motor.....................86
Right Instrument Panel Speaker...................72
Right Liftgate Speaker.........................72
Right Front Door Window Connector and Window Lift
Switch Function Chart........................87
Right Rear Door Jamb Switch....................76
Right Rear Door Window Connector and Window Lift
Function Chart.............................88
Right Rear Wheel Sensor.......................29
Right Turn Relay.............................97
Seat Belt Switch.............................74
Seat Belt Warning Indicator Lamp................57,58
Sensors
Ambient Temperature Sensor...................53
Camshaft Position Sensor...................11,20
Crankshaft Position Sensor...................11,20
Engine Coolant Temperature Sensor.............14,19
G Sensor................................30
Heated Oxygen Sensor.....................13,21
Intake Air Temperature Sensor................14,19
Left Front Wheel Sensor......................29
Left Rear Wheel Sensor.......................29
MAP Sensor............................14,19
Pedal Travel Sensor.........................30
Right Front Wheel Sensor.....................29
Right Rear Wheel Sensor......................29
JWIRING DIAGRAMS 8W - 153

WIRING DIAGRAMS XJ-RHD
INDEX
Wiring Diagram Name Sheet Number
A/C Compressor Clutch........................45
A/C Compressor Clutch Relay....................45
A/C Heater Blower Motor.......................46
A/C Low Pressure Switch.......................45
A/C Mode Selector Switch.......................46
A/C System.............................45, 46
A/C Thermostat..............................45
Antenna Mast...............................47
Ashtray Illumination Lamp.......................26
Automatic Shut Down Relay......................9
Back-up Lamp Switch.........................16
Battery....................................6
Blower Motor............................44, 46
Blower Resistor...........................44, 46
Blower Switch............................44, 46
Body Ground...............................59
Brake Warning Switch.........................42
Camshaft Position Sensor.......................12
Cargo Lamp................................30
Charging System.............................5
Generator.................................5
Check Engine Indicator Lamp..................39, 40
Chime Module..............................43
Chime Module Connector.......................71
Cigar Lighter...............................58
Circuit Breakers
Windshield Wiper Circuit Breaker...............2,33
Connectors
Chime Module Connector......................71
Dash to Instrument Panel Connector A.............64
Dash to Instrument Panel Connector B.............65
Dash to Instrument Panel Connector C.............66
Data Link Connector.........................10
Instrument Cluster Connector 16 Way...........37, 69
Main Body Connector 1.......................70
Power Mirror Connector......................61
Powertrain Control Module Connector..............73
Steering Column Connector 11 Way...............67
Telltale Connector........................38, 68
Transmission Control Module Connector............72
Transmission Data Link Connector................17
Coolant Temperature Switch......................16
Crankshaft Position Sensor......................12
Dash to Instrument Panel Connector A..............64
Dash to Instrument Panel Connector B..............65
Dash to Instrument Panel Connector C..............66
Data Link Connector..........................10
Distributor Ignition Coil........................10
Dome Lamp................................31
Dome and Courtesy Lamps.................29, 30, 31
Cargo Lamp..............................30
Dome Lamp..............................31Wiring Diagram Name Sheet Number
Dome/Reading Lamp.........................31
Glove Box Lamp...........................29
Reading Lamp.............................31
Vanity Lamps.............................31
Dome/Reading Lamp..........................31
Door Jamb Switch System....................49, 50
Left Front Door Jamb Switch...................50
Left Rear Door Jamb Switch...................50
Liftgate Switch............................46
Right Front Door Jamb Switch..................49
Right Rear Door Jamb Switch..................49
Electronic Fuel Injection
Ignition System................9,10,11,12,13,14
Automatic Shut Down Relay.....................9
Camshaft Position Sensor.....................12
Crankshaft Position Sensor.....................12
Data Link Connector.........................10
Distributor Ignition Coil.......................10
Engine Coolant Temperature Sensor...............11
Fuel Injectors.............................14
Fuel Pump Relay............................9
Heated Oxygen Sensor.......................13
Idle Air Control Motor........................14
Intake Air Temp Sensor.......................11
Map Sensor..............................11
Powertrain Control Module........9,10,11,12,13,14
Throttle Position (Sensor).....................11
Engine Block Heater...........................58
Engine Coolant Temperature Sensor................11
Engine Coolant Temperature Switch.................15
Engine Oil Pressure and Temperature System..........15
Engine Oil Pressure Switch......................15
Engine Starter System..........................6
Battery..................................6
Engine Starter Motor.........................6
Engine Starter Relay..........................6
Fan Control Relay...........................3,7
Fog Lamp Illumination Lamp.....................20
Fog Lamp Relay.............................21
Fog Lamp Switch............................20
4WD Select Trac Indicator Lamp................39, 40
Front Axle Switch............................16
Front End Lighting.........................21, 22
Fog Lamp Relay...........................21
Left Fog Lamp.............................21
Left Headlamp.............................21
Left Park/Turn Signal Lamp....................21
Left Side Marker Lamp.......................21
Right Fog Lamp............................22
Right Headlamp............................22
Right Park/Turn Signal Lamp...................22
Right Side Marker Lamp......................22
Front Wipers/Washer - Intermittent..............33, 34
JWIRING DIAGRAMS 8W - 271

Wiring Diagram Name Sheet Number
Dome/Reading Lamp.........................31
Fog Lamps............................21, 22
Fog Lamp Illumination Lamp...................20
4WD Select Trac Indicator Lamp..............39, 40
Front Headlamps.........................21, 22
Full Time Indicator Lamp...................39, 40
Glove Box Lamp...........................29
Heated Rear Window Lamp....................25
Heater A/C Panel Lamp.......................25
High-Beam Indicator Lamp.....................41
Instrument Cluster Illumination Lamps.............41
Left Backup Lamp..........................55
Left Fog Lamp.............................21
Left Headlamp.............................21
Left Park/Turn Signal Lamp....................21
Left Side Marker...........................55
Left Side Marker Lamp (Front)..................21
Left Tail/Stop Lamp.........................55
Left Turn Indicator Lamp......................41
Left Turn Lamp (Amber)......................55
License Lamp.............................55
Low Washer Indicator Lamp.................39, 40
Maintenance Required Indicator Lamp...........39, 40
Malfunction Indicator Lamp..................39, 40
Park Brake Indicator Lamp.....................40
Park/Turn Signal Lamps....................21, 22
Reading Lamp.............................31
Rear Wiper/Wash Switch Lamp..................26
Right Back-up Lamp.........................56
Right Fog Lamp............................22
Right Headlamp............................22
Right Park/Turn Signal Lamp...................22
Right Side Marker..........................56
Right Side Marker Lamp (Front).................22
Right Tail/Stop Lamp........................56
Right Turn Indicator Lamp.....................41
Right Turn Lamp (Amber).....................56
Seat Belt Indicator Lamp...................39, 40
Side Marker Lamps (Front)..................21, 22
Transfer Case Lamp.........................26
Transmission Range Lamp.....................26
Underhood Lamp...........................28
Upshift Indicator Lamp.....................39, 40
Vanity Lamps.............................31
LCD Illumination Relay.........................57
Left Front Door Jamb Switch.....................50
Left Rear Door Jamb Switch.....................50
Left Speakers............................47, 48
Liftgate Switch..............................50
Low Washer Indicator Lamp...................39, 40
Main Body Connector 1........................70
Maintenance Required Indicator Lamp............39, 40
Map Sensor................................11
Modules
Chime Module.............................43
Fuel Pump Module..........................54
Intermittent Wiper Module.....................33
Powertrain Control Module . .7, 9, 10, 11, 12, 13, 14, 45, 53Wiring Diagram Name Sheet Number
Transmission Control Module.................17, 18
Motors
A/C Heater Blower Motor......................46
Engine Starter Motor.........................6
Front Wiper Motor..........................34
Heater Blower Motor.........................44
Idle Air Control Motor........................14
Radiator Fan Motor..........................7
Rear Wiper Motor..........................36
Oil Pressure and Temperature System...............15
Coolant Temperature Switch....................15
Oil Pressure Switch.........................15
Park Brake Indicator Lamp......................40
Park Brake Switch............................42
Power Distribution Center........................1
Power Distribution Center Application Chart............4
Power Distribution Center Identification...............3
Power Mirror Connector........................61
Power Mirror Switch Assembly...................51
Power Mirrors............................51, 52
Heater Element............................52
Left Power Mirror..........................52
Right Power Mirror.........................52
Powertrain Control Module . . .7, 9, 10, 11, 12, 13, 14, 45, 53
Powertrain Control Module Connector...............73
Pumps
Front Washer.............................34
Rear Washer..............................35
Fuel...................................54
Radiator Fan Motor............................7
Radio.................................47, 48
Antenna Mast.............................47
Left Instrument Panel Speaker..................47
Left Liftgate Speaker.........................48
Radio..................................47
Right Instrument Panel Speaker.................48
Right Liftgate Speaker........................48
Rear Lighting............................55, 56
Left Back-Up Lamp..........................55
Left Side Marker...........................55
Left Tail/Stop Lamp.........................55
Left Turn Lamp (Amber)......................55
License Lamp.............................55
Right Back-Up Lamp.........................56
Right Side Marker..........................56
Right Tail/Stop Lamp........................56
Right Turn Lamp (Amber).....................56
Rear Wiper/Washer.........................35, 36
Rear Washer Pump.........................35
Rear Wiper Motor..........................36
Rear Wiper/Washer Switch.....................35
Reading Lamps..............................31
Relays
A/C Compressor Clutch Relay.................3,45
Automatic Shut Down Relay...................3,9
Engine Starter Relay........................3,6
Fan Control Relay.........................3,7
Fog Lamp Relay...........................21
JWIRING DIAGRAMS 8W - 273

Wiring Diagram Name Sheet Number
Fuel Pump Relay..........................3,9
Heated Rear Window Relay....................60
Horn Relay...............................27
LCD Illumination Relay.......................57
Right Front Door Jamb Switch....................49
Right Rear Door Jamb Switch....................49
Right Speaker...............................48
Seat Belt Switch.............................43
Seat Belt Indicator Lamp.....................39, 40
Sensors
Camshaft Position Sensor.....................12
Crankshaft Position Sensor.....................12
Engine Coolant Temperature Sensor...............11
Fuel Gauge Sensor..........................54
Heated Oxygen Sensor.......................13
Intake Air Temperature Sensor..................11
Map Sensor..............................11
Throttle Position Sensor......................11
Vehicle Speed Sensor........................16
Speakers, Radio...........................47, 48
Splices
Splice A3..............................1,19
Splice A11................................5
Splice A14................................9
Splice A21................................9
Splice A21-1............................8,43
Splice A48.............................2,33
Splice A142..............................14
Splice A142-1.............................14
Splice A142-2.........................5,10,14
Splice C7................................46
Splice C15...............................52
Splice C15-1..............................52
Splice C43............................44, 46
Splice C90...............................45
Splice E2................................25
Splice F12...............................10
Splice F85.............................47, 58
Splice G7.............................12, 16
Splice K4................................11
Splice K4-1...............................11
Splice K6................................11
Splice K7................................12
Splice K22...............................11
Splice K29................................9
Splice L3................................21
Splice L90...............................55
Splice L90-1..............................22
Splice L90-2..............................56
Splice L90-3..............................55
Splice M1................................31
Splice M1-1..............................29
Splice M2................................30
Splice M2-1..............................29
Splice M2-2..............................30
Splice P79...............................51
Splice V32...............................53
Splice Z1-1...............................59Wiring Diagram Name Sheet Number
Splice Z1-2...............................20
Splice Z1-3...............................32
Splice Z1-4...............................28
Splice Z1-5............................59, 60
Splice Z1-6...............................55
Splice Z1-7...............................56
Splice Z1-10..............................22
Splice Z1-13..............................51
Splice Z1-14...............................7
Splice Z1-15..............................59
Splice Z1-16..............................16
Splice Z11...............................10
Splice Z12-1..............................13
Splice 117...............................21
Starter System...............................6
Battery..................................6
Engine Starter Motor.........................6
Engine Starter Relay..........................6
Steering Column Connector 11 Way................67
Stop Lamp Switch............................24
Stop/Turn and Hazard System..................23, 24
Hazard Flasher.............................24
Hazard Switch.............................24
Stop Lamp Switch..........................24
Turn and Hazard Flasher Switch.................24
Turn Signal Flasher..........................23
Switches
A/C Low Pressure Switch.....................45
A/C Mode Selector Switch.....................46
Back-Up Lamp Switch........................16
Blower Switch..........................44, 46
Brake Warning Switch........................42
Engine Coolant Temperature Switch...............15
Engine Oil Pressure Switch....................15
Fog Lamp Switch...........................20
Front Axle Switch...........................16
Hazard Switch.............................24
Headlamp Dimmer Switch.....................19
Headlamp Switch.........................1,19
Heated Rear Window Switch....................60
Heat Mode Select Switch......................44
Horn Switch..............................27
Ignition Key Warning Switch....................43
Ignition Switch.............................8
Left Front Door Jamb Switch...................50
Left Rear Door Jamb Switch...................50
Liftgate Switch............................50
Oil Pressure Switch.........................15
Park Brake Switch..........................42
Park Switch (Wiper).........................34
Power Mirror Switch.........................51
Rear Wiper/Washer Switch.....................35
Reed Switch..............................18
Right Front Door Jamb Switch..................49
Right Rear Door Jamb Switch..................49
Seat Belt Switch...........................43
Stop Lamp Switch..........................24
Transmission Range Switch....................17
8W - 274 WIRING DIAGRAMSJ

can easily be wiped off. Components should be
torqued in place within 15 minutes. The use of a lo-
cating dowel is recommended during assembly to pre-
vent smearing the material off location.
ENGINE PERFORMANCE
To provide best vehicle performance and lowest ve-
hicle emissions, it is most important that the tune-up
be done accurately. Use the specifications listed on
the Vehicle Emission Control Information label
found on the engine compartment hood.
(1) Test battery specific gravity. Add water, if nec-
essary. Clean and tighten battery connections.
(2) Test cranking amperage draw (refer to Group
8B, Battery/Starter Service for the proper proce-
dures).
(3) Tighten the intake manifold bolts (refer to
Group 11, Exhaust System and Intake Manifold for
the proper specifications).
(4) Perform cylinder compression test:
(a) Check engine oil level and add oil, if neces-
sary.
(b) Drive the vehicle until engine reaches normal
operating temperature.
(c) Select a route free from traffic and other
forms of congestion, observe all traffic laws and
briskly accelerate through the gears several times.
The higher engine speed may help clean out valve
seat deposits which can prevent accurate compres-
sion readings.
CAUTION: DO NOT overspeed the engine.
(d) Remove all spark plugs from engine. As
spark plugs are being removed, check electrodes for
abnormal firing indicators - fouled, hot, oily, etc.
Record cylinder number of spark plug for future
reference.
(e) Disconnect coil wire from distributor and se-
cure to good ground to prevent a spark from start-
ing a fire.
(f) Be sure throttle blades are fully open during
the compression check.
(g) Insert compression gage adaptor into the
No.1 spark plug hole. Crank engine until maxi-
mum pressure is reached on gauge. Record this
pressure as No.1 cylinder pressure.
(h) Repeat Step 4g for all remaining cylinders.
(i) Compression should not be less than 689 kPa
(100 psi) and not vary more than 172 kPa (25 psi)
from cylinder to cylinder.
(j) If cylinder(s) have abnormally low compres-
sion pressures, repeat steps 4a through 4h.
(k) If the same cylinder(s) repeat an abnormally
low reading, it could indicate the existence of a
problem in the cylinder.
The recommended compression pressures are
to be used only as a guide to diagnosing engineproblems. An engine should NOT be disassem-
bled to determine the cause of low compression
unless some malfunction is present.
(5) Clean or replace spark plugs as necessary. Ad-
just gap (refer to Group 8D, Ignition System for gap
adjustment and torque).
(6) Test resistance of spark plug cables (refer to
Group 8D, Ignition System).
(7) Inspect the primary wire. Test coil output volt-
age, primary and secondary resistance. Replace parts
as necessary (refer to Group 8D, Ignition System and
make necessary adjustment).
(8) Set ignition timing to specifications (refer to
Specification Label on engine compartment hood).
(9) Perform a combustion analysis.
(10) Test fuel pump for pressure and vacuum (refer
to Group 14, Fuel System for the proper specifica-
tions).
(11) Inspect air filter element (refer to Group 0,
Lubrication and Maintenance for the proper proce-
dure).
(12) Inspect crankcase ventilation system (refer to
Group 0, Lubrication and Maintenance for the proper
procedure).
(13) For emission controls refer to Group 25, Emis-
sion Controls System for service procedures.
(14) Inspect and adjust accessory belt drives (refer
to Group 7, Cooling System for the proper adjust-
ments).
(15) Road test vehicle as a final test.
HONING CYLINDER BORES
Before honing, stuff plenty of clean shop towels un-
der the bores and over the crankshaft to keep abra-
sive materials from entering the crankshaft area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823 equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). 20-60 strokes, de-
pending on the bore condition, will be sufficient to
provide a satisfactory surface. Using honing oil
C-3501-3880 or a light honing oil available from ma-
jor oil distributors.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits or kerosene.
9 - 2 ENGINESJ

CONNECTING ROD BEARING CLEARANCE
Engine connecting rod bearing clearances can be
determined by use of Plastigage, or equivalent. The
following is the recommended procedures for the use
of Plastigage:
(1) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(2) Place a piece of Plastigage across the entire
width of the bearing cap shell (Fig. 2). Position the
Plastigage approximately 6.35 mm (1/4 inch) off cen-
ter and away from the oil holes. In addition, suspect
areas can be checked by placing the Plastigage in the
suspect area.
(3) The crankshaft must be turned until the con-
necting rod to be checked starts moving toward the
top of the engine. Only then should the rod cap with
Plastigage in place be assembled. Tighten the rod
cap nut to 45 Nzm (33 ft. lbs.) torque.DO NOT ro-
tate the crankshaft or the Plastigage may be
smeared, giving inaccurate results.
(4) Remove the bearing cap and compare the width
of the flattened Plastigage with the scale provided on
the package (Fig. 3). Plastigage generally comes in 2
scales (one scale is in inches and the other is a met-
ric scale). Locate the band closest to the same width.
This band shows the amount of clearance. Differ-
ences in readings between the ends indicate the
amount of taper present. Record all readings taken
(refer to Engine Specifications).
(5) Plastigage is available in a variety of clearance
ranges. The 0.025-0.076 mm (0.001-0.003 inch) range
is usually the most appropriate for checking engine
bearing clearances.
REPAIR DAMAGED OR WORN THREADS
Damaged or worn threads can be repaired. Essen-
tially, this repair consists of:
²Drilling out worn or damaged threads.
²Tapping the hole with a special Heli-Coil Tap, or
equivalent.
²Installing an insert into the tapped hole.
This brings the hole back to its original thread size.
CAUTION: Be sure that the tapped holes maintain
the original center line.Heli-Coil tools and inserts are readily available
from automotive parts jobbers.
SERVICE ENGINE ASSEMBLY (SHORT BLOCK)
A service replacement engine assembly (short
block) may be installed whenever the original cylin-
der block is defective or damaged beyond repair. It
consists of the cylinder block, crankshaft, piston and
rod assemblies. If needed, the camshaft must be pro-
cured separately and installed before the engine is
installed in the vehicle.
A short block is identified with the letter ``S'' stamped
on the same machined surface where the build date
code is stamped for complete engine assemblies.
Installation includes the transfer of components
from the defective or damaged original engine. Fol-
low the appropriate procedures for cleaning, inspec-
tion and torque tightening.
HYDROSTATIC LOCK
When an engine is suspected of hydrostatic lock
(regardless of what caused the problem), follow the
steps below.
(1) Perform the Fuel Pressure Release Procedure
(refer to Group 14, Fuel System).
(2) Disconnect the negative cable from the battery.
(3) Inspect air cleaner, induction system and in-
take manifold to ensure system is dry and clear of
foreign material.
(4) Place a shop towel around the spark plugs to
catch any fluid that may possibly be under pressure in
the cylinder head. Remove the plugs from the engine.
CAUTION: DO NOT use the starter motor to rotate
the crankshaft. Severe damage could occur.
(5) With all spark plugs removed, rotate the crank-
shaft using a breaker bar and socket.
(6) Identify the fluid in the cylinders (i.e. coolant,
fuel, oil, etc.).
(7) Make sure all fluid has been removed from the
cylinders.
(8) Repair engine or components as necessary to
prevent this problem from occurring again.
(9) Squirt engine oil into the cylinders to lubricate
the walls. This will prevent damage on restart.
(10) Install new spark plugs. Tighten the spark
plugs to 37 Nzm (27 ft. lbs.) torque.
(11) Drain engine oil. Remove and discard the oil
filter.
(12) Install the drain plug. Tighten the plug to 34
Nzm (25 ft. lbs.) torque.
(13) Install a new oil filter.
(14) Fill engine crankcase with the specified
amount and grade of oil (refer to Group 0, Lubrica-
tion and Maintenance).
(15) Connect the negative cable to the battery.
(16) Start the engine and check for any leaks.
Fig. 3 Clearance Measurement
9 - 4 ENGINESJ

ENGINE DIAGNOSIS
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine tune-ups.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or me-
chanical (e.g., a strange noise).
Refer to the Service DiagnosisÐPerformance chart
and the Service DiagnosisÐMechanical chart for pos-
sible causes and corrections of malfunctions. Refer to
Group 14, Fuel System for the fuel system diagnosis.
Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts. In-
formation concerning additional tests and diagnosis
is provided within the following diagnosis:
²Cylinder Compression Pressure Test.
²Cylinder Combustion Pressure Leakage Test.
²Engine Cylinder Head Gasket Failure Diagnosis.
²Intake Manifold Leakage Diagnosis.
INTAKE MANIFOLD LEAKAGE DIAGNOSIS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
METHOD 1
(1) Start the engine.
(2) Open the acetylene valve of an oxyacetylene
torch. DO NOT ignite.
(3) Pass the torch tip over the exposed gasket area
(EDGE) between the manifold and the engine cylin-
der head.
(4) If the engine speed increases, the manifold has
an air leak.
METHOD 2
(1) Start the engine.
(2) Apply engine oil to the exposed gasket area
(EDGE) between the manifold and the engine cylin-
der head.
(3) If oil is forced into the manifold and if smoke is
visible from the exhaust tailpipe, the manifold has
an air leak.
CYLINDER COMPRESSION PRESSURE TEST
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs.
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the 3rd
revolution. Continue the test for the remaining cyl-
inders.
Refer to Engine Specifications for the correct en-
gine compression pressures.
ENGINE CYLINDER HEAD GASKET FAILURE
DIAGNOSIS
A leaking engine cylinder head gasket usually re-
sults in loss of power, loss of coolant and engine mis-
firing.
An engine cylinder head gasket leak can be located
between adjacent cylinders or between a cylinder and
the adjacent water jacket.
²An engine cylinder head gasket leaking between
adjacent cylinders is indicated by a loss of power
and/or engine misfire.
²An engine cylinder head gasket leaking between a
cylinder and an adjacent water jacket is indicated by
coolant foaming or overheating and loss of coolant.
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is
leaking between adjacent cylinders; follow the proce-
dures outlined in Cylinder Compression Pressure
Test. An engine cylinder head gasket leaking be-
tween adjacent cylinders will result in approximately
a 50-70% reduction in compression pressure.
CYLINDER-TO-WATER JACKET LEAKAGE
TEST
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
Remove the radiator cap.
Start the engine and allow it to warm up until the
engine thermostat opens.
If a large combustion/compression pressure leak ex-
ists, bubbles will be visible in the coolant.
If bubbles are not visible, install a radiator pres-
sure tester and pressurize the coolant system.
JENGINES 9 - 5