spark plugs DODGE RAM 2003 Service Owner's Guide

DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION PRESSURE
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) Disable the fuel system (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - DESCRIPTION).
(5) Remove the ASD relay (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/AUTO SHUT DOWN
RELAY - REMOVAL).
(6) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(7) Record the compression pressure on the 3rd
revolution. Continue the test for the remaining cylin-
ders.
(8) (Refer to 9 - ENGINE - SPECIFICATIONS) for
the correct engine compression pressures.
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:²Exhaust and intake valve leaks (improper seat-
ing).
²Leaks between adjacent cylinders or into water
jacket.
²Any causes for combustion/compression pressure
loss.
(1) Check the coolant level and fill as required. DO
NOT install the radiator cap.
(2) Start and operate the engine until it attains
normal operating temperature, then turn the engine
OFF.
(3) Remove the spark plugs.
(4) Remove the oil filler cap.
(5) Remove the air cleaner hose.
(6) Calibrate the tester according to the manufac-
turer's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
(7) Perform the test procedures on each cylinder
according to the tester manufacturer's instructions.
Set piston of cylinder to be tested at TDC compres-
sion,While testing, listen for pressurized air escaping
through the throttle body, tailpipe and oil filler cap
opening. Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
Refer to CYLINDER COMBUSTION PRESSURE
LEAKAGE DIAGNOSIS CHART.
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
9 - 182 ENGINE - 5.7LDR
ENGINE - 5.7L (Continued)

DIAGNOSIS AND TESTINGÐENGINE DIAGNOSIS - LUBRICATION
CONDITION POSSIBLE CAUSES CORRECTION
OIL LEAKS 1. Gaskets and O-Rings. 1.
(a) Misaligned or damaged. (a) Replace as necessary.
(b) Loose fasteners, broken or
porous metal parts.(b) Tighten fasteners, Repair or
replace metal parts.
2. Crankshaft rear seal 2. Replace as necessary.
3. Crankshaft seal flange.
Scratched, nicked or grooved.3. Polish or replace crankshaft.
4. Oil pan flange cracked. 4. Replace oil pan.
5.Front cover seal, damaged or
misaligned.5. Replace seal.
6. Scratched or damaged vibration
damper hub.6. Polish or replace damper.
OIL PRESSURE DROP 1. Low oil level. 1. Check and correct oil level.
2. Faulty oil pressure sending unit. 2. Replace sending unit.
3. Low oil pressure. 3. Check pump and bearing
clearance.
4. Clogged oil filter. 4. Replace oil filter.
5. Worn oil pump. 5. Replace as necessary.
6. Thin or diluted oil. 6. Change oil and filter.
7. Excessive bearing clearance. 7. Replace as necessary.
8. Oil pump relief valve stuck. 8. Replace oil pump.
9. Oil pickup tube loose or
damaged.9. Replace as necessary.
OIL PUMPING AT RINGS; SPARK
PLUGS FOULING1. Worn or damaged rings. 1. Hone cylinder bores and replace
rings.
2. Carbon in oil ring slots. 2. Replace rings.
3. Incorrect ring size installed. 3. Replace rings.
4. Worn valve guides. 4. Ream guides and replace valves.
5. Leaking intake gasket. 5. Replace intake gaskets.
6. Leaking valve guide seals. 6. Replace valve guide seals.
DRENGINE - 5.7L 9 - 183
ENGINE - 5.7L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
4. Excessive main bearing clearance 4. Measure bearings for correct
clearance. Repair as necessary
5. Excessive end play 5. Check crankshaft thrust bearing for
excessive wear on flanges
6. Crankshaft main journal out of
round or worn6. Grind journals or replace crankshaft
7. Loose flywheel or torque converter 7. Inspect crankshaft, flexplate/
flywheel and bolts for damage.
Tighten to correct torque
LOW OIL PRESSURE 1. Low oil level 1. Check oil level and fill if necessary
2. Faulty oil pressure sending unit 2. Install new sending unit
3. Clogged oil filter 3. Install new oil filter
4. Worn oil pump 4. Replace oil pump assembly.
5. Thin or diluted oil 5. Change oil to correct viscosity.
6. Excessive bearing clearance 6. Measure bearings for correct
clearance
7. Oil pump relief valve stuck 7. Remove valve to inspect, clean and
reinstall
8. Oil pickup tube loose, broken, bent
or clogged8. Inspect oil pickup tube and pump,
and clean or replace if necessary
9. Oil pump cover warped or cracked 9. Install new oil pump
OIL LEAKS 1. Misaligned or deteriorated gaskets 1. Replace gasket
2. Loose fastener, broken or porous
metal part2. Tighten, repair or replace the part
3. Front or rear crankshaft oil seal
leaking3. Replace seal
4. Leaking oil gallery plug or cup plug 4. Remove and reseal threaded plug.
Replace cup style plug
EXCESSIVE OIL CONSUMPTION OR
SPARK PLUGS OIL FOULED1. CCV System malfunction 1. (Refer to 25 - EMISSIONS
CONTROL/EVAPORATIVE
EMISSIONS - DESCRIPTION) for
correct operation
2. Defective valve stem seal(s) 2. Repair or replace seal(s)
3. Worn or broken piston rings 3. Hone cylinder bores. Install new
rings
4. Scuffed pistons/cylinder walls 4. Hone cylinder bores and replace
pistons as required
5. Carbon in oil control ring groove 5. Remove rings and de-carbon piston
6. Worn valve guides 6. Inspect/replace valve guides as
necessary
7. Piston rings fitted too tightly in
grooves7. Remove rings and check ring end
gap and side clearance. Replace if
necessary
DRENGINE - 5.7L 9 - 185
ENGINE - 5.7L (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - REPAIR DAMAGED
OR WORN THREADS
CAUTION: Be sure that the tapped holes maintain
the original center line.
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 to bring
the hole back to its original thread size.
STANDARD PROCEDUREÐHYDROSTATIC
LOCK
CAUTION: DO NOT use the starter motor to rotate
the crankshaft. Severe damage could occur.
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 14 - FUEL SYSTEM/FUEL DELIVERY -
STANDARD PROCEDURE).
(2) Disconnect the negative cable(s) from the bat-
tery.
(3) Inspect air cleaner, induction system, and
intake 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 spark plugs.
(5) With all spark plugs removed, rotate the crank-
shaft using a breaker bar and socket.
(6) Identify the fluid in the cylinders (coolant, fuel,
oil, etc.).
(7) Be 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 a small amount of 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 41 N´m (30 ft. lbs.) torque.
(11) Drain engine oil. Remove and discard the oil
filter.
(12) Install the drain plug. Tighten the plug to 34
N´m (25 ft. lbs.) torque.
(13) Install a new oil filter.(14) Fill engine crankcase with the specified
amount and grade of oil. (Refer to LUBRICATION &
MAINTENANCE - SPECIFICATIONS).
(15) Connect the negative cable(s) to the battery.
(16) Start the engine and check for any leaks.
REMOVAL
(1) Disconnect the battery negative cable.
(2) Remove the air cleaner resonator and duct
work as an assembly.
(3) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(4) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(5) Remove the viscous fan/drive (Refer to 7 -
COOLING/ENGINE/RADIATOR FAN - REMOVAL).
(6) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(7) Remove the upper crossmember and top core
support.
NOTE: It is not necessary to drain A/C system for
engine removal.
(8) Remove the A/C compressor with the lines
attached. Secure compressor out of the way.
(9) Remove generator assembly (Refer to 8 -
ELECTRICAL/CHARGING/GENERATOR - REMOV-
AL).
(10) Perform the Fuel System Pressure Release
procedure (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE).
(11) Remove the intake manifold and IAFM as an
assembly(Refer to 9 - ENGINE/MANIFOLDS/IN-
TAKE MANIFOLD - REMOVAL).
(12) Disconnect the heater hoses.
NOTE: It is not necessary to disconnect P/S hoses
from pump, for P/S pump removal.
(13) Remove the power steering pump and set
aside.
(14) Disconnect the fuel supply line (Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY/QUICK CON-
NECT FITTING - STANDARD PROCEDURE).
(15) Raise and support the vehicle on a hoist and
drain the engine oil.
(16) Remove engine front mount thru-bolt nuts.
(17) Disconnect the transmission oil cooler lines
from their retainers at the oil pan bolts.
(18) Disconnect exhaust pipe at manifolds.
(19) Disconnect the starter wires. Remove starter
motor (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - REMOVAL).
9 - 186 ENGINE - 5.7LDR
ENGINE - 5.7L (Continued)

TORQUE
TORQUE CHART 5.7L ENGINE
DESCRIPTION N´m Ft. In.
Lbs. Lbs.
Block Pipe Plugs
(1/4 NPT)20 Ð 177
(3/8 NPT) 27 Ð 240
Camshaft SprocketÐBolt 122 90 Ð
Camshaft Tensioner
PlateÐBolts28 Ð 250
Timing Chain Case CoverÐ
Bolts28 Ð 250
Lifting Stud 55 40 Ð
Connecting Rod CapÐBolts 21
plus
90É
Turn15
plus
90É
TurnÐ
Main Bearing CapÐBolts
M-1227
plus
90É
TurnÐÐ
Crossbolts
M-828 Ð Ð
Cylinder HeadÐBolts
M-12 Bolts
Step 1 34 25 Ð
Step 2 54 40 Ð
Step 3 Turn
90ÉTurn
90ÉÐ
M-8 Bolts Ð
Step 1 20 15 Ð
Step 2 34 25 Ð
Cylinder Head CoverÐBolts 8 Ð 70
Exhaust Manifold to Cylinder
Head25 Ð 220
FlywheelÐBolts 95 70 Ð
Front InsulatorÐThrough
bolt/nut95 70 Ð
Front Insulator to Support
Bracket
ÐStud Nut (4WD) 41 30 Ð
ÐThrough Bolt/Nut (4WD) 102 75 Ð
Front Insulator to BlockÐ
Bolts (2WD)95 70 Ð
GeneratorÐMounting Bolt 55 40 Ð
Intake ManifoldÐBolts Refer to Procedure
DESCRIPTION N´m Ft. In.
Oil PanÐBolts 12 Ð 105
Oil Dipstick Tube 12 Ð 105
Oil PanÐDrain Plug 34 25 Ð
Oil PumpÐAttaching Bolts 28 Ð 250
Oil Pump Pickup Tube ± Bolt
and Nut28 Ð 250
Rear Seal Retainer Attaching
Bolts15 Ð 132
Rear Insulator to BracketÐ 68 50 Ð
Through-Bolt (2WD)
Rear Insulator to
Crossmember41 30 Ð
Support BracketÐNut (2WD)
Rear Insulator to
CrossmemberÐ68 50 Ð
Nuts (4WD)
Rear Insulator to
TransmissionÐ68 50 Ð
Bolts (4WD)
Rear Insulator BracketÐBolts 68 50 Ð
(4WD Automatic)
Rear Support Bracket to 41 30 Ð
Crossmember FlangeÐNuts
Rear Support Plate to
Transfer41 30 Ð
CaseÐBolts
Rocker ArmÐBolts 22 Ð 195
Spark Plugs Ð Ð Ð
Thermostat HousingÐBolts 28 Ð 250
Throttle BodyÐBolts 12 Ð 105
Transfer Case to Insulator 204 105 Ð
Mounting PlateÐNuts
Transmission Support
BracketÐ68 50 Ð
Bolts (2WD)
Vibration DamperÐBolt 176 129 Ð
Water Pump to Timing Chain 28 Ð 250
Case CoverÐBolts
DRENGINE - 5.7L 9 - 191
ENGINE - 5.7L (Continued)

CAUTION: The head gaskets are marked ªTOPº to
indicate which side goes up.
(4) Position cylinder heads onto head gaskets and
cylinder block.
(5) Tighten the cylinder head bolts in three steps
(Fig. 4):
²Step 1Ð Snug tighten M12 cylinder head bolts,
in sequence, to 34 N´m (25 ft. lbs.) and M8 bolts to
20 N´m (15 ft. lbs.) torque.
²Step 2Ð Tighten M12 cylinder head bolts, in
sequence, to 54 N´m (40 ft. lbs.) and verify M8 bolts
to 20 N´m (15 ft. lbs.) torque..
²Step 3Ð Turn M12 cylinder head bolts, in
sequence, 90 degrees and tighten M8 bolts to 34 N´m
(25 ft. lbs.) torque.
(6) Install push rods and rocker arm assemblies in
their original position.
(7) Install the intake manifold and throttle body
assembly.
(8) If required, adjust spark plugs to specifications.
Install the plugs.
(9) Connect the heater hoses.
(10) Install the fuel supply line.
(11) Install the generator and drive belt.
(12) Install cylinder head covers(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(13) Connect the evaporation control system.
(14) Install the air cleaner.
(15) Fill cooling system.
(16) Connect the negative cable to the battery.
(17) Start engine check for leaks.CYLINDER HEAD COVER(S)
REMOVAL
(1) Disconnect battery negative cable.
(2) Disconnect coil on plug connectors.
CAUTION: The ground straps must be installed in
the same location as removed. The covers are
machined to accept the ground straps in those
locations only.
(3) Remove cylinder head cover retaining bolts,
and ground straps.
(4) Remove cylinder head cover.
NOTE: The gasket may be used again, provided no
cuts, tears, or deformation has occurred.
INSTALLATION
CAUTION: Do not use harsh cleaners to clean the
cylinder head covers. Severe damage to covers
may occur.
CAUTION: DO NOT allow other components includ-
ing the wire harness to rest on or against the
engine cylinder head cover. Prolonged contact with
other objects may wear a hole in the cylinder head
cover.
(1) Clean cylinder head cover and both sealing sur-
faces. Inspect and replace gasket as necessary.
(2)
Install cylinder head cover and hand start all fas-
teners. Verify that all double ended studs are in the cor-
rect location and install left and right ground straps.
CAUTION: The ground straps must be installed in
the same location as removed. The covers are
machined to accept the ground straps in those
locations only.
NOTE: The right hand ground strap is located on
the front inboard stud. The left hand ground strap
is located on the rear inboard stud.
(3) Tighten cylinder head cover bolts and double
ended studs to 8 N´m (70 in. lbs). Begin torque
sequence in the middle of head cover and torque
bolts moving outward in a crisscross pattern from top
to bottom.
(4) Install ignition coil on plug, and torque fasten-
ers to 12 N´m (105 in. lbs)
(5) Connect, ignition coil electrical connectors.
(6) Install PCV hose.
(7) Connect battery negative cable.
Fig. 4 CYLINDER HEAD TIGHTENING SEQUENCE
9 - 196 ENGINE - 5.7LDR
CYLINDER HEAD (Continued)

VALVE SPRINGS
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove air cleaner assembly.
(3) Remove air intake resonator.
(4) Remove spark plug cables.
(5) Remove ignition coil connectors (Fig. 6).
(6) Remove ignition coils.
(7) Remove one spark plug.
(8) Remove valve cover.
CAUTION: The piston must be at TDC, and both
valves closed on the cylinder to be serviced.
(9) Remove exhaust/intake rocker arm shafts.
(10) Install spring compressor, special tool# 9065.NOTE: All valve springs and seals are removed in
the same manner.
(11) Charge cylinder with air.
NOTE: Tap the top of the valve spring retainer to
loosen the spring retainers locks.
(12) Compress valve spring and remove valve
retainer locks.
(13) Release spring compressor and remove valve
spring.
NOTE: The valve springs are interchangeable
between intake and exhaust.
(14) Remove valve seal.
INSTALLATION
(1) Install valve seal.
(2) Install valve spring.
(3) Using special tool# 9065, compress valve spring
and install valve spring retainer and locks.
(4) Release air charge in cylinder.
(5) Remove spring compressor tool # 9065.
CAUTION: Verify that the pushrods are fully seated
into lifter and rocker arm. Recheck after rocker arm
shaft has been torqued to specification.
(6) Install rocker arm shaft and pushrods(Refer to
9 - ENGINE/CYLINDER HEAD/ROCKER ARM /
ADJUSTER ASSY - INSTALLATION).
(7) Tighten the rocker shaft bolts to 22 N´m (195
in. lbs.) torque,using the following sequence:Center,
center-right, center-left, right, left.
(8) Install cylinder head cover.
(9) Tighten cylinder head cover bolts and double
ended studs(Refer to 9 - ENGINE/CYLINDER
HEAD/CYLINDER HEAD COVER(S) - INSTALLA-
TION) .
(10) Install spark plugs.
(11) Install ignition coil on plug, and torque fasten-
ers to 12 N´m (105 in. lbs)
(12) Install ignition coil connectors.
(13) Install spark plug cables.
(14) Install air intake resonator.
(15) Install air cleaner assembly.
(16) Connect negative battery cable.
Fig. 6 IGNITION COIL R/I Ð 5.7L V-8
1 - SLIDE LOCK (SLIDE OUTWARD TO UNLOCK)
2 - SPARK PLUG CABLE (TO OPPOSITE CYLINDER BANK
SPARK PLUG)
3 - RELEASE LOCK / TAB (PUSH HERE)
4 - ELEC. CONNECTOR
5 - IGNITION COIL
6 - COIL MOUNTING BOLTS (2)
7 - SPARK PLUG CABLE (TO OPPOSITE CYLINDER BANK
IGNITION COIL)
DRENGINE - 5.7L 9 - 199

DIAGNOSIS AND TESTINGÐENGINE DIAGNOSIS - PERFORMANCE
PERFORMANCE DIAGNOSIS CHARTÐGASOLINE ENGINES
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT CRANK 1. Weak or dead battery 1. Charge/Replace Battery. (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/
BATTERY - STANDARD PROCEDURE).
Check charging system. (Refer to 8 -
ELECTRICAL/CHARGING - DIAGNOSIS
AND TESTING).
2. Corroded or loose battery connections 2. Clean/tighten suspect battery/starter
connections
3. Faulty starter or related circuit(s) 3. Check starting system. (Refer to 8 -
ELECTRICAL/STARTING - DIAGNOSIS
AND TESTING)
4. Seized accessory drive component 4. Remove accessory drive belt and
attempt to start engine. If engine starts,
repair/replace seized component.
5. Engine internal mechanical failure or
hydro-static lock5. Refer to (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
ENGINE CRANKS BUT
WILL NOT START1. No spark 1. Check for spark. (Refer to 8 -
ELECTRICAL/IGNITION CONTROL -
DESCRIPTION)
2. No fuel 2. Perform fuel pressure test, and if
necessary, inspect fuel injector(s) and
driver circuits. (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY/FUEL PUMP -
DIAGNOSIS AND TESTING).
3. Low or no engine compression 3. Perform cylinder compression pressure
test. (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING).
ENGINE LOSS OF POWER 1. Worn or burned distributor rotor 1. Install new distributor rotor
2. Worn distributor shaft 2. Remove and repair distributor (Refer to
8 - ELECTRICAL/IGNITION CONTROL/
DISTRIBUTOR - REMOVAL).
3. Worn or incorrect gapped spark plugs 3. Clean plugs and set gap. (Refer to 8 -
ELECTRICAL/IGNITION CONTROL/
SPARK PLUG - CLEANING).
4. Dirt or water in fuel system 4. Clean system and replace fuel filter
5. Faulty fuel pump 5. Install new fuel pump
6. Incorrect valve timing 6. Correct valve timing
7. Blown cylinder head gasket 7. Install new cylinder head gasket
8. Low compression 8. Test cylinder compression (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING).
9. Burned, warped, or pitted valves 9. Install/Reface valves as necessary
10. Plugged or restricted exhaust system 10. Install new parts as necessary
11. Faulty ignition cables 11. Replace any cracked or shorted cables
9 - 226 ENGINE - 5.9LDR
ENGINE - 5.9L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
12. Faulty ignition coil 12. Test and replace, as necessary (Refer
to 8 - ELECTRICAL/IGNITION CONTROL/
IGNITION COIL - REMOVAL).
ENGINE STALLS OR
ROUGH IDLE1. Carbon build-up on throttle plate 1. Remove throttle body and de-carbon.
(Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/THROTTLE BODY -
REMOVAL).
2. Engine idle speed too low 2. Check Idle Air Control circuit. (Refer to
14 - FUEL SYSTEM/FUEL INJECTION/
IDLE AIR CONTROL MOTOR -
DESCRIPTION)
3. Worn or incorrectly gapped spark plugs 3. Replace or clean and re-gap spark
plugs (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG -
CLEANING)
4. Worn or burned distributor rotor 4. Install new distributor rotor
5. Spark plug cables defective or crossed 5. Check for correct firing order or replace
spark plug cables. (Refer to 8 -
ELECTRICAL/IGNITION CONTROL/
SPARK PLUG CABLE - DIAGNOSIS AND
TESTING)
6. Faulty coil 6. Test and replace, if necessary (Refer to
8 - ELECTRICAL/IGNITION CONTROL/
IGNITION COIL - REMOVAL)
7. Intake manifold vacuum leak 7. Inspect intake manifold gasket and
vacuum hoses (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING).
ENGINE MISSES ON
ACCELERATION1. Worn or incorrectly gapped spark plugs 1. Replace spark plugs or clean and set
gap. (Refer to 8 - ELECTRICAL/IGNITION
CONTROL/SPARK PLUG - CLEANING)
2. Spark plug cables defective or crossed 2. Replace or rewire secondary ignition
cables. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
CABLE - REMOVAL)
3. Dirt in fuel system 3. Clean fuel system
4. Burned, warped or pitted valves 4. Install new valves
5. Faulty coil 5. Test and replace as necessary (Refer to
8 - ELECTRICAL/IGNITION CONTROL/
IGNITION COIL - REMOVAL)
DRENGINE - 5.9L 9 - 227
ENGINE - 5.9L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
4. Excessive main bearing clearance 4. Measure bearings for correct
clearance. Repair as necessary
5. Excessive end play 5. Check crankshaft thrust bearing for
excessive wear on flanges
6. Crankshaft main journal out of
round or worn6. Grind journals or replace crankshaft
7. Loose flywheel or torque converter 7. Inspect crankshaft, flexplate/
flywheel and bolts for damage.
Tighten to correct torque
LOW OIL PRESSURE 1. Low oil level 1. Check oil level and fill if necessary
2. Faulty oil pressure sending unit 2. Install new sending unit
3. Clogged oil filter 3. Install new oil filter
4. Worn oil pump 4. Replace oil pump assembly.
5. Thin or diluted oil 5. Change oil to correct viscosity.
6. Excessive bearing clearance 6. Measure bearings for correct
clearance
7. Oil pump relief valve stuck 7. Remove valve to inspect, clean and
reinstall
8. Oil pickup tube loose, broken, bent
or clogged8. Inspect oil pickup tube and pump,
and clean or replace if necessary
9. Oil pump cover warped or cracked 9. Install new oil pump
OIL LEAKS 1. Misaligned or deteriorated gaskets 1. Replace gasket
2. Loose fastener, broken or porous
metal part2. Tighten, repair or replace the part
3. Front or rear crankshaft oil seal
leaking3. Replace seal
4. Leaking oil gallery plug or cup plug 4. Remove and reseal threaded plug.
Replace cup style plug
EXCESSIVE OIL CONSUMPTION OR
SPARK PLUGS OIL FOULED1. CCV System malfunction 1. (Refer to 25 - EMISSIONS
CONTROL/EVAPORATIVE
EMISSIONS - DESCRIPTION) for
correct operation
2. Defective valve stem seal(s) 2. Repair or replace seal(s)
3. Worn or broken piston rings 3. Hone cylinder bores. Install new
rings
4. Scuffed pistons/cylinder walls 4. Hone cylinder bores and replace
pistons as required
5. Carbon in oil control ring groove 5. Remove rings and de-carbon piston
6. Worn valve guides 6. Inspect/replace valve guides as
necessary
7. Piston rings fitted too tightly in
grooves7. Remove rings and check ring end
gap and side clearance. Replace if
necessary
DRENGINE - 5.9L 9 - 229
ENGINE - 5.9L (Continued)