1998 DODGE RAM 1500 Engine control 2

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) Disable the fuel system (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - DESCRIPTION).
(4) Remove the ASD relay (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/AUTO SHUT DOWN
RELAY - REMOVAL).
(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 revo-
lution. Continue the test for the remaining cylinders.
(7) (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:
²
Exhaust and intake valve leaks (improper seating).
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
DRENGINE - 4.7L 9 - 93
ENGINE - 4.7L (Continued)

(19) Disconnect throttle and speed control cables.
(20) Disconnect tube from both the left and right
side crankcase breathers (Fig. 2). Remove breathers
(21) Discharge A/C system (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/REFRIG-
ERANT - STANDARD PROCEDURE).
(22) Remove A/C compressor (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - REMOVAL).
(23) Remove shroud, fan assembly (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - REMOVAL) and accessory drive belt
(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE
BELTS - REMOVAL).
(24) Disconnect transmission oil cooler lines at the
radiator.
(25) Disconnect radiator upper and lower hoses.
(26) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL), A/C condenser
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/A/C CONDENSER - REMOVAL) and
transmission oil cooler.
(27) Remove generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - REMOVAL).
(28) Disconnect the two heater hoses from the tim-
ing chain cover and heater core.
(29) Unclip and remove heater hoses and tubes
from the intake manifold.
(30) Disconnect engine harness at the following
points :
²Intake air temperature (IAT) sensor (Fig. 3)
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold absolute pressure (MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs(31) Disconnect the vacuum lines at the throttle
body and intake manifold.
(32) Release fuel rail pressure (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - STANDARD PROCE-
DURE) then disconnect the fuel supply quick connect
fitting at the fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/QUICK CONNECT FITTING -
STANDARD PROCEDURE).
(33) Remove power steering pump and position out
of the way.
(34) Install Special Tools 8400 Lifting Studs, into
the cylinder heads.
(35) Install Engine Lifting Fixture Special Tool
8347 (Fig. 4) following these steps.
²Holding the lifting fixture at a slight angle, slide
the large bore in the front plate over the hex portion
of the lifting stud.
²Position the two remaining fixture arms onto
the two Special Tools 8400 Lifting Studs, in the cyl-
inder heads.
²Pull foward and upward on the lifting fixture so
that the lifting stud rest in the slotted area below the
large bore.
Fig. 2 Crankcase Breather Connection Points
1 - CRANKCASE BREATHERS
Fig. 3 Throttle Body Connection Points
1 - THROTTLE BODY
2 - TPS
3 - IAC MOTOR
4 - IAT SENSOR
5 - MOUNTING SCREWS
9 - 96 ENGINE - 4.7LDR
ENGINE - 4.7L (Continued)

Position both the left and right side engine mount
brackets and install the through bolts and nuts.
Tighten nuts to4X2 vehicles95 N´m (70 ft. lbs.).
4X4 vehicles102 N´m (75 ft. lbs.).
(2)4X4 vehiclesInstall locknuts onto the engine
mount brackets. Tighten locknuts to 41 N´m (30 ft.
lbs.).
(3) Remove jack from under the transmission.
(4) Remove Engine Lifting Fixture Special Tool
8347 (Fig. 4).
(5) Remove Special Tools 8400 Lifting Studs.
(6) Position generator wiring behind the oil dip-
stick tube, then install the oil dipstick tube upper
mounting bolt.
(7) Connect both left and right side body ground
straps.
(8) Install power steering pump.
(9) Connect fuel supply line quick connect fitting
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
QUICK CONNECT FITTING - STANDARD PROCE-
DURE).
(10) Connect the vacuum lines at the throttle body
and intake manifold.
(11) Connect engine harness at the following
points (Fig. 3):
²Intake Air Temperature (IAT) Sensor
²Idle Air Control (IAC) Motor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure (MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
(12) Position and install heater hoses and tubes
onto intake manifold.
(13) Install the heater hoses onto the heater core
and the engine front cover.
(14) Install generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - INSTALLATION).
(15) Install A/C condenser (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/A/C CON-
DENSER - INSTALLATION), radiator (Refer to 7 -
COOLING/ENGINE/RADIATOR - INSTALLATION)
and transmission oil cooler.
(16) Connect radiator upper and lower hoses.
(17) Connect the transmission oil cooler lines to
the radiator.
(18) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -INSTALLATION), fan assembly and shroud (Refer to
7 - COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - INSTALLATION).
(19) Install A/C compressor (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - INSTALLATION).
(20) Install both breathers. Connect tube to both
crankcase breathers (Fig. 2).
(21) Connect throttle and speed control cables.
(22) Install throttle body resonator assembly and
air inlet hose. Tighten clamps 4 N´m (35 in. lbs.).
(23) Raise vehicle.
(24) Install transmission to engine mounting bolts.
Tighten the bolts to 41 N´m (30 ft. lbs.).
(25) Install torque converter bolts (Automatic
Transmission Only).
(26) Connect crankshaft position sensor (Fig. 1).
(27)4X4 vehiclesPosition and install the axle
isolator bracket onto the axle, transmission and
engine block. Tighten bolts to specification (Refer to 9
- ENGINE - SPECIFICATIONS).
(28) Install starter (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - INSTALLATION).
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(29) Install structural cover (Refer to 9 - ENGINE/
ENGINE BLOCK/STRUCTURAL COVER - INSTAL-
LATION).
(30) Install exhaust crossover pipe.
(31) Install engine block heater power cable, If
equipped.
(32)4X4 vehiclesConnect axle vent tube to left
side engine mount.
(33) Lower vehicle.
(34) Check and fill engine oil.
(35) Recharge the A/C system (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/REFRIG-
ERANT - STANDARD PROCEDURE).
(36) Refill the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(37) Install the battery tray and battery.
(38) Connect the battery positive and negative
cables.
(39) Start the engine and check for leaks.
9 - 98 ENGINE - 4.7LDR
ENGINE - 4.7L (Continued)

SPECIFICATIONS
SPECIFICATIONS - 4.7L ENGINE
GENERAL DESCRIPTION
DESCRIPTION SPECIFICATION
Engine Type 90É SOHC V-8 16-Valve
Displacement 4.7 Liters / 4701 cc
287 ( Cubic Inches)
Bore 93.0 mm (3.66 in.)
Stroke 86.5 mm (3.40 in.)
Compression Ratio 9.0:1
Horsepower 235 BHP @ 4800 RPM
Torque 295 LB-FT @ 3200 RPM
Lead Cylinder #1 Left Bank
Firing Order 1-8-4-3-6-5-7-2
CYLINDER BLOCK
DESCRIPTION SPECIFICATION
Metric Standard
Bore Diameter 93.010   .0075
mm3.6619   0.0003
in.
Out of Round
(MAX)0.076 mm 0.003 in.
Taper (MAX) 0.051 mm 0.002 in.
PISTONS
DESCRIPTION SPECIFICATION
Metric Standard
Diameter 92.975 mm 3.6605 in.
Weight 366 grams 12.9 oz
Ring Groove
Diameter
No. 1 83.37 - 83.13
mm3.282 - 3.273 in
No. 2 82.833 - 83.033
mm3.261 - 3.310 in.
No. 3 83.88 - 84.08
mm3.302 - 3.310 in.
PISTON PINS
DESCRIPTION SPECIFICATION
Metric Standard
Clearance In
Piston0.010 - 0.019
mm0.0004 - 0.0008
in.
Diameter 24.013 - 24.016
mm0.9454 - 0.9455
in.
PISTON RINGS
DESCRIPTION SPECIFICATION
Metric Standard
Ring Gap
To p
Compression
Ring0.20 - 0.36 mm 0.0079 - 0.0142
in.
Second
Compression
Ring0.37 - 0.63 mm 0.0146 - 0.0249
in.
Oil Control
(Steel Rails)0.25 - 0.76 mm 0.0099 - 0.30 in.
Side Clearance
To p
Compression
Ring.051 - .094 mm 0.0020 - 0.0037
in.
Second
Compression
Ring0.040 - 0.080
mm0.0016 - 0.0031
in.
Oil Ring (Steel
Ring).019 - .229 mm .0007 - .0091 in.
Ring Width
To p
Compression
Ring1.472 - 1.490
mm0.057 - 0.058 in.
Second
Compression
Ring1.472 - 1.490
mm0.057 - 0.058 in.
Oil Ring (Steel
Rails)0.445 - 0.470
mm0.017 - 0.018 in.
DRENGINE - 4.7L 9 - 99
ENGINE - 4.7L (Continued)

the camshaft, four on the steel tube and one on the
steel nose piece. Camshaft end play is controlled by
two thrust walls that border the nose piece journal.
Engine oil enters the hollow camshafts at the third
journal and lubricates every intake lobe rocker
through a drilled passage in the intake lobe.
REMOVAL
CAUTION: When the timing chain is removed and
the cylinder heads are still installed, DO NOT force-
fully rotate the camshafts or crankshaft indepen-
dently of each other. Severe valve and/or piston
damage can occur.
CAUTION: When removing the cam sprocket, timing
chains or camshaft, Failure to use Special Tool
8350 will result in hydraulic tensioner ratchet over
extension, requiring timing chain cover removal to
reset the tensioner ratchet.
(1) Remove cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) Set engine to TDC cylinder #1, camshaft
sprocket V8 marks at the 12 o'clock position.
(3) Mark one link on the secondary timing chain
on both sides of the V8 mark on the camshaft
sprocket to aid in installation.CAUTION: Do not hold or pry on the camshaft tar-
get wheel (Located on the right side camshaft
sprocket) for any reason, Severe damage will occur
to the target wheel resulting in a vehicle no start
condition.
(4) Loosen butDO NOTremove the camshaft
sprocket retaining bolt. Leave the bolt snug against
the sprocket.
NOTE: The timing chain tensioners must be
secured prior to removing the camshaft sprockets.
Failure to secure tensioners will allow the tension-
ers to extend, requiring timing chain cover removal
in order to reset tensioners.
CAUTION: Do not force wedge past the narrowest
point between the chain strands. Damage to the
tensioners may occur.
(5) Position Special Tool 8350 timing chain wedge
between the timing chain strands, tap the tool to
securely wedge the timing chain against the ten-
sioner arm and guide (Fig. 25).
NOTE: When gripping the camshaft, place the pliers
on the tube portion of the camshaft only. Do not
grip the lobes or the sprocket areas.
Fig. 25 Securing Timing Chain Tensioners Using Timing Chain Wedge
1 - LEFT CYLINDER HEAD
2 - RIGHT CYLINDER HEAD3 - SPECIAL TOOL 8350 WEDGE
4 - SPECIAL TOOL 8350 WEDGE
DRENGINE - 4.7L 9 - 115
CAMSHAFT(S) - LEFT (Continued)

CAMSHAFT(S) - RIGHT
DESCRIPTION
The camshafts consist of powdered metal steel lobes
which are sinter-bonded to a steel tube. A steel post or
nose piece is friction-welded to the steel camshaft tube.
Five bearing journals are machined into the camshaft,
four on the steel tube and one on the steel nose piece.
Camshaft end play is controlled by two thrust walls
that border the nose piece journal. Engine oil enters the
hollow camshafts at the third journal and lubricates
every intake lobe rocker through a drilled passage in
the intake lobe.
REMOVAL
CAUTION: When the timing chain is removed and
the cylinder heads are still installed, DO NOT force-
fully rotate the camshafts or crankshaft indepen-
dently of each other. Severe valve and/or piston
damage can occur.
CAUTION: When removing the cam sprocket, timing
chains or camshaft, Failure to use special tool 8350
will result in hydraulic tensioner ratchet over exten-
sion, Requiring timing chain cover removal to re-set
the tensioner ratchet.(1) Remove the cylinder head covers (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) Set engine to TDC cylinder #1, camshaft
sprocket V8 marks at the 12 o'clock position.
(3) Mark one link on the secondary timing chain
on both sides of the V8 mark on the camshaft
sprocket to aid in installation.
CAUTION: Do not hold or pry on the camshaft tar-
get wheel for any reason, Severe damage will occur
to the target wheel. A damaged target wheel could
cause a vehicle no start condition.
(4)
Loosen butDO NOTremove the camshaft
sprocket retaining bolt. Leave bolt snug against sprocket.
NOTE: The timing chain tensioners must be
secured prior to removing the camshaft sprockets.
Failure to secure tensioners will allow the tension-
ers to extend, requiring timing chain cover removal
in order to reset tensioners.
CAUTION: Do not force wedge past the narrowest
point between the chain strands. Damage to the
tensioners may occur.
(5) Position Special Tool 8350 timing chain wedge
between the timing chain strands. Tap the tool to
securely wedge the timing chain against the ten-
sioner arm and guide (Fig. 32).
Fig. 32 Securing Timing Chain Tensioners Using Timing Chain Wedge
1 - LEFT CYLINDER HEAD
2 - RIGHT CYLINDER HEAD3 - SPECIAL TOOL 8350 WEDGE
4 - SPECIAL TOOL 8350 WEDGE
DRENGINE - 4.7L 9 - 119

base circle. Depress part of rocker arm over adjuster.
Normal adjusters should feel very firm. Spongy
adjusters can be bottomed out easily.
b. Remove suspected lash adjusters, and replace.
c. Before installation, make sure adjusters are at
least partially full of oil. This can be verified by little
or no plunger travel when lash adjuster is depressed.
REMOVAL
NOTE: Disconnect the battery negative cable to pre-
vent accidental starter engagement.
(1) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) For rocker arm removal on cylinders 3 and 5
Rotate the crankshaft until cylinder #1 is at TDC
exhaust stroke.
(3) For rocker arm removal on cylinders 2 and 8
Rotate the crankshaft until cylinder #1 is at TDC
compression stroke.
(4) For rocker arm removal on cylinders 4 and 6
Rotate the crankshaft until cylinder #3 is at TDC
compression stroke.
(5) For rocker arm removal on cylinders 1 and 7
Rotate the crankshaft until cylinder #2 is at TDC
compression stroke.
(6) Using special tool 8516 Rocker Arm Remover,
press downward on the valve spring, remove rocker
arm (Fig. 45).
INSTALLATION
CAUTION: Make sure the rocker arms are installed
with the concave pocket over the lash adjusters.
Failure to do so may cause severe damage to the
rocker arms and/or lash adjusters.
NOTE: Coat the rocker arms with clean engine oil
prior to installation.
(1) For rocker arm installation on cylinders 3 and
5 Rotate the crankshaft until cylinder #1 is at TDC
exhaust stroke.
(2) For rocker arm installation on cylinders 2 and
8 Rotate the crankshaft until cylinder #1 is at TDC
compression stroke.
(3) For rocker arm installation on cylinders 4 and
6 Rotate the crankshaft until cylinder #3 is at TDC
compression stroke.
(4) For rocker arm installation on cylinders 1 and
7 Rotate the crankshaft until cylinder #2 is at TDC
compression stroke.
(5) Using special tool 8516 press downward on the
valve spring, install rocker arm (Fig. 45).
(6) Install the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
VALVE SPRINGS
DESCRIPTION
The valve springs are made from high strength
chrome silicon steel. The springs are common for
intake and exhaust applications. The valve spring
seat is integral with the valve stem seal, which is a
positive type seal to control lubrication.
REMOVAL
(1) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) Using Special Tool 8516 Rocker Arm Remover,
remove the rocker arms and the hydraulic lash
adjusters (Fig. 46).
(3) Remove the spark plug for the cylinder the
valve spring and seal are to be removed from.
(4) Apply shop air to the cylinder to hold the
valves in place when the spring is removed
(5) Remove the camshaft (Refer to 9 - ENGINE/
CYLINDER HEAD/CAMSHAFT(S) - REMOVAL).
NOTE: All eight valve springs and seals are
removed in the same manner; this procedure only
covers one valve seal and valve spring.
Fig. 45 Rocker ArmÐRemoval
1 - CAMSHAFT
2 - SPECIAL TOOL 8516
9 - 126 ENGINE - 4.7LDR
ROCKER ARM / ADJUSTER ASSEMBLY (Continued)

(6) Using Special Tool 8387 Valve Spring Compres-
sor, compress the valve spring.
NOTE: It may be necessary to tap the top of the
valve spring to loosen the spring retainers locks
enough to be removed.
(7) Remove the two spring retainer lock halves.
NOTE: the valve spring is under tension use care
when releasing the valve spring compressor.
(8) Remove the valve spring compressor.
(9) Remove the spring retainer, and the spring.
(10) Remove the valve stem seal.
NOTE: The valve stem seals are common between
intake and exhaust.
INSTALLATION
(1) coat the valve stem with clean engine oil and
install the valve stem seal. Make sure the seal is
fully seated and that the garter spring at the top of
the seal is intact.
(2) Install the spring and the spring retainer (Fig.
47).
(3) Using Special Tool 8387 Valve Spring Compres-
sor, compress the spring and install the two valve
spring retainer halves.(4) Release the valve spring compressor and make
sure the two spring retainer halves and the spring
retainer are fully seated.
(5) Install the camshaft (Refer to 9 - ENGINE/
CYLINDER HEAD/CAMSHAFT(S) - INSTALLA-
TION).
(6) Position the hydraulic lash adjusters and
rocker arms (Fig. 46).
(7) Install the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
VALVE STEM SEALS
DESCRIPTION
The valve stem seals are made of rubber and incor-
porate an integral steel valve spring seat. The inte-
gral garter spring maintains consistent lubrication
control to the valve stems.
Fig. 46 Rocker ArmÐRemoval
1 - CAMSHAFT
2 - SPECIAL TOOL 8516
Fig. 47 Valve Assembly Configuration
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
DRENGINE - 4.7L 9 - 127
VALVE SPRINGS (Continued)