fuel filter CHRYSLER VOYAGER 1996 User Guide

cause of low compression unless some malfunc-
tion is present.
(11) Clean or replace spark plugs as necessary
and adjust gap as specified in Group 8, Electrical.
Tighten to specifications.
(12) Test resistance of spark plug cables. Refer to
Group 8, Electrical Ignition System Secondary Cir-
cuit Inspection.
(13) Test coil output voltage, primary and second-
ary resistance. Replace parts as necessary. Refer to
Group 8, Electrical Ignition System.
(14) Check fuel pump pressure at idle and differ-
ent RPM ranges. Refer to Group 14, Fuel System for
Specifications.
(15) The air filter elements should be replaced as
specified in Group 0, Lubrication and Maintenance,.
(16) Inspect crankcase ventilation system as out
lined in Group 0, Lubrication and Maintenance. For
emission controls see Group 25, Emission Controls
for service procedures.
(17) Inspect and adjust accessory belt drives refer-
ring to Group 7, Cooling System, Accessory Drive
Belts for proper adjustments.
(18) Road test vehicle as a final test.
CYLINDER COMBUSTION PRESSURE LEAKAGE
TEST
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.
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn the engine
OFF.
Clean spark plug recesses with compressed air.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er'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.Perform the test procedures on each cylinder
according to the tester manufacturer's instructions.
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.
LASH ADJUSTER (TAPPET) NOISE DIAGNOSIS
A tappet-like noise may be produced from several
items. Check the following items.
(1) Engine oil level too high or too low. This may
cause aerated oil to enter the adjusters and cause
them to be spongy.
(2) Insufficient running time after rebuilding cylin-
der head. Low speed running up to 1 hour may be
required.
(3) During this time, turn engine off and let set for
a few minutes before restarting. Repeat this several
times after engine has reached normal operating
temperature.
(4) Low oil pressure.
(5) The oil restrictor pressed into the vertical oil
passage to the cylinder head is plugged with debris.
(6) Air ingested into oil due to broken or cracked
oil pump pick up.
(7) Worn valve guides.
(8) Rocker arm ears contacting valve spring
retainer.
(9) Rocker arm loose, adjuster stuck or at maxi-
mum extension and still leaves lash in the system.
(10) Faulty lash adjuster.
a. Check lash adjusters for sponginess while
installed in cylinder head. 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 disassem-
bleDo not reuse retainer caps. Do not inter-
change parts and make sure that care and
cleanliness is exercised in the handling of parts.
c. Clean out dirt and varnish with solvent.
d. Reassemble with engine oil.
e. Check for sponginess.
f. If still spongy, replace with new adjuster.
INSPECTION (ENGINE OIL LEAKS IN GENERAL)
Begin with a through visual inspection of the
engine, particularly at the area of the suspected leak.
If an oil leak source is not readily identifiable, the
following steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
9 - 8 ENGINENS
DIAGNOSIS AND TESTING (Continued)

ENGINE DIAGNOSISÐPERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery. 1. Test battery. Charge or replace
as necessary.Refer to Group 8A,
Battery.
2. Corroded or loose battery
connections.2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to terminals.
3. Faulty starter. Test starting system. Refer to Group
8B, Starting.
4. Moisture on ignition wires. 4. Remove moisture from wires.
5. Faulty ignition cables. 5. Replace any cracked or shorted
cables.
6. Faulty coil or control unit. 6. Test and replace as needed.
Refer to Group 8D, Ignition System
7. Incorrect spark plug gap. 7. Set gap. Refer to Group 8D,
Ignition System.
8. Contamination in fuel system. 8. Clean system and replace fuel
filter.
9. Faulty fuel pump. 9. Test fuel pump and replace as
needed. Refer to Group 14, Fuel
System.
ENGINE STALLS OR IDLES
ROUGH1. Idle speed too low. 1. Test minimum air flow. Refer to
Group 14, Fuel System.
2. Incorrect fuel mixture. 2. Refer to Group 14, Fuel System.
3. Intake manifold leakage. 3. Inspect intake manifold, manifold
gasket, and vacuum hoses. Refer to
Group 11, Exhaust System and
Intake Manifold.
4. Incorrect ignition wiring. 4. Install correct wiring.
5. Faulty coil(s) 5. Test and replace as necessary.
Refer to Group 8D, Ignition System.
ENGINE LOSS OF POWER 1. Dirty or incorrectly gapped plugs. 1. Clean plugs and set gap. Refer to
Group 8D, Ignition System.
2. Contamination in fuel system. 2. Clean system and replace fuel
filter.
3. Faulty fuel pump. 3. Test and replace as necessary.
Refer to Group 14, Fuel System.
4. Incorrect valve timing. 4. Correct valve timing.
5. Leaking cylinder head gasket. 5. Replace cylinder head gasket.
6. Low compression. 6. Test compression of each
cylinder.
7. Burned, warped, or pitted valves. 7. Replace valves.
8. Plugged or restricted exhaust
system.8. Install new parts, as necessary.
9. Faulty ignition cables. 9. Replace any cracked or shorted
cables.
10. Faulty coil(s). 10. Test and replace as necessary.
Refer to Group 8D, Ignition System.
9 - 10 ENGINENS
DIAGNOSIS AND TESTING (Continued)

CONDITION POSSIBLE CAUSE CORRECTION
ENGINE MISSES ON
ACCELERATION1. Dirty or incorrectly gapped spark
plugs.1. Clean spark plugs and set gap.
Refer to Group 8D, Ignition System.
2. Contamination in Fuel System. 2. Clean fuel system and replace
fuel filter.
3. Burned, warped, or pitted valves. 3. Replace valves.
4. Faulty coil(s). 4. Test and replace as necessary.
Refer to Group 8D, Ignition System.
ENGINE MISSES AT HIGH SPEED 1. Dirty or incorrect spark plug gap. 1. Clean spark plugs and set gap.
Refer to Group 8D, Ignition System.
2. Faulty coil(s). 2. Test and replace as necessary.
Refer to Group 8D, Ignition System.
3. Dirty fuel injector(s). Test and replace as necessary.
Refer to Group 14, Fuel System.
4. Contamination in fuel system. 4. Clean system and replace fuel
filter.
NSENGINE 9 - 11
DIAGNOSIS AND TESTING (Continued)

ENGINE ASSEMBLY
REMOVAL
(1) Perform fuel pressure release procedure. Refer
to Group 14, Fuel System for procedure. Remove fuel
line to fuel rail.
(2) Disconnect battery.
(3) Remove Air cleaner and hoses.
(4) Drain cooling system. Refer to Group 7, Cooling
System for procedure.
(5) Remove upper radiator hose and remove radia-
tor fans. Refer to Group 7, Cooling System for proce-
dure.
(6) Remove lower radiator hose.
(7) Disconnect automatic transmission cooler lines
and plug, if equipped.
(8) Disconnect transmission shift linkage.
(9) Disconnect throttle body linkage.
(10) Disconnect engine wiring harness.
(11) Disconnect heater hoses.
(12) Discharge Air Conditioning System. Refer to
Group 24, Air Conditioning for procedure.
(13) Hoist vehicle and remove right inner splash
shield. Remove wheels and tires.
(14) Loosen power steering belt for pump removal.
Refer to Group 7, Cooling System for procedure.
(15) Remove axle shafts. Refer to Group 2, Suspen-
sion and Driveshafts for procedure.
(16) Disconnect exhaust pipe from manifold.
(17) Remove front and rear engine mount brackets
from the body.
(18) Remove bending braces and front engine
mount bracket. Remove transmission inspection
cover.
(19) Mark flexplate to torque converter and
remove torque converter bolts.
(20) Install front engine mount bracket.
(21) Lower vehicle.
(22) Remove power steering pump. Set pump
aside.
(23) Remove A/C lines at compressor and cap.
(24) Remove ground straps to body.
(25) Raise vehicle enough to allow engine dolly
Special Tool 6135, cradle Special Tool 6710 with
Posts Special Tool 6848 and Adaptor Special Tool
8130 to be installed under vehicle (Fig. 27).
(26) Loosen cradle posts to allow movement for
proper positioning. Locate two rear posts (right side
of engine) into the holes on the engine bedplate.
Locate the two front posts (left side of engine) on the
front engine bracket and A/C compressor bracket
(Fig. 27). Lower vehicle and position cradle mounts
until the engine is resting on mounts. Tighten
mounts to cradle frame. This will keep mounts from
moving when removing or installing engine and
transmission.(27) Lower vehicle so the weight ofONLY THE
ENGINE AND TRANSMISSIONare on the cradle.
(28) Remove engine and transmission mount bolts.
(29) Raise vehicle slowly. It may be necessary to
move the engine/transmission assembly on the cradle
to allow for removal around the body.
INSTALLATION
(1) Position engine and transmission assembly
under vehicle and slowly lower the vehicle over the
engine and transmission.
(2) Align engine and transmission mounts to
attaching points. Install mounting bolts at the right
engine and left transmission mounts. Refer to proce-
dures outlined in this section.
(3) Slowly raise vehicle enough to remove the
engine dolly and cradle Special Tools 6135 and 6710.
(4) Install axle shafts. Refer to Group 2, Suspen-
sion and Driveshafts for procedure.
(5) Install transmission and engine braces and
splash shields.
(6) Connect exhaust system to manifold. Refer to
Group 11, Exhaust System and Intake Manifold for
procedure and torque specifications.
(7) Install power steering pump. Refer to Cooling
System Group 7, Accessory Drive Section for belt ten-
sion adjustment.
(8) Install A/C compressor hoses. Refer to Group
24, Heater and Air Conditioning for procedure.
(9) Install accessory drive belts. Refer to Group 7,
Cooling System Accessory Drive Section for belt ten-
sion adjustment.
(10) Install front and rear engine mounts. Refer to
this section for procedure.
(11) Install inner splash shield. Install wheels and
tires.
(12) Connect automatic transmission cooler lines,
and shift linkage. Refer to Group 21, Transmission
for procedures.
(13) Connect fuel line and heater hoses.
(14) Install ground straps. Connect engine and
throttle body connections and harnesses. Refer to
Group 8, Electrical for procedure.
(15) Connect throttle body linkage. Refer to Group
14, Fuel System for procedure.
(16) Install radiator fans. Install radiator hoses.
Fill cooling system. Refer to Group 7, Cooling System
for filling procedure.
(17) Connect battery.
(18) Install air cleaner and hoses.
(19) Install oil filter. Fill engine crankcase with
proper oil to correct level.
(20) Start engine and run until operating temper-
ature is reached.
(21) Adjust transmission linkage, if necessary.
9 - 26 2.4L ENGINENS
REMOVAL AND INSTALLATION (Continued)

(25) Remove ground straps to body.
(26) Raise vehicle enough to allow engine dolly
Special Tool 6135 and cradle Special Tool 6710 with
post Special Tool 6848 and adaptor Special Tool 6909
to be installed under vehicle (Fig. 24).
(27) Loosen cradle engine mounts to allow move-
ment for positioning onto engine locating holes on the
engine. Lower vehicle and position cradle mounts
until the engine is resting on mounts. Tighten
mounts to cradle frame. This will keep mounts from
moving when removing or installing engine and
transmission.
(28) Lower vehicle so the weight ofONLY THE
ENGINE AND TRANSMISSIONis on the cradle.
(29) Remove right engine mount assembly and left
transmission mount through bolt. Refer to Engine
Mounts Section of this Group.
(30) Raise vehicle slowly. It may be necessary to
move the engine/transmission assembly on the cradle
to allow for removal around body flanges.
INSTALLATION
(1) Position engine and transmission assembly
under vehicle and slowly lower the vehicle over the
engine and transmission. It may be necessary to
move the engine/transmission assembly with the cra-
dle for clearance around body flanges.
(2) Align engine and transmission mounts to
attaching points. Install mounting bolts at the right
engine and left transmission mounts. Refer to proce-
dures outlined in this section.(3) Slowly raise vehicle enough to remove the
engine dolly and cradle Special Tools 6135, 6710,
6848 and 6909.
(4) Remove Special tools 6910 and install bending
braces.
(5) Lower vehicle. Install generator and wiring
harness.
(6) Connect wiring harness on the front of the
engine.
(7) Install Air Conditioning Compressor.
(8) Install power steering pump and bracket and
accessory drive belt. Refer to Group 7. Accessory
Drive Belts Section for installation procedure.
(9) Raise vehicle and install axle shafts. Refer to
Group 2, Driveshafts for procedure.
(10) Install transmission and engine mount and
bracket assemblies. Refer to Engine Mounts in this
section for procedure.
(11) Connect exhaust system to manifold. Refer to
Group 11, Exhaust System and Intake Manifold for
procedure and torque specifications.
(12) Install left and right inner splash shields.
(13) Connect automatic transmission shifter link-
age. Refer to Group 21, Transmission for procedures.
(14) Lower vehicle and connect fuel line and
heater hoses. Remove plugs from rear heater hoses
and install, if equipped.
(15) Install ground straps. Connect engine and
throttle body connections and harnesses.
(16) Connect throttle body linkage. Refer to Group
14, Fuel System for procedure.
(17) Install radiator and fan module assembly.
Install radiator hoses. Fill cooling system. Refer to
Group 7, Cooling for procedures.
(18) Install battery tray, battery and cover.
(19) Install air cleaner and hoses.
(20) Install oil filter. Fill engine crankcase with
proper oil to correct level.
(21) Start engine and run until operating temper-
ature is reached.
(22) Adjust transmission linkage, if necessary.
CYLINDER HEAD COVER
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove air inlet resonator when removing left
head cover.
(3) When Removing left cylinder head cover,
remove dipstick tube.
(4) When removing right cylinder head cover
remove wiper unit. Refer to Wiper Unit Removal in
Group 8K.
(5) When removing right cylinder head cover,
remove accessory drive belt. Refer to Accessory Drive
Belt Removal in Group 7.
Fig. 24 Positioning Engine Cradle Support Post
MountsÐTypical
9 - 70 3.0L ENGINENS
REMOVAL AND INSTALLATION (Continued)

(20) Remove rear transmission mount and bracket.
(21) Remove power steering pump and bracket
assembly.
(22) Remove wiring harness and connectors from
front of engine.
(23) Remove bending braces and install tool num-
ber 6912 on engine.
(24) Remove transmission inspection cover and
mark flexplate to torque converter.
(25) Remove driveplate to torque converter bolts.
(26) Lower the vehicle.
(27) Remove ground straps to body.
(28) Raise vehicle enough to allow engine dolly
Special Tool 6135 and cradle Special Tool 6710 with
post Special Tool 6848 and adaptor Special Tool 6909
to be installed under vehicle (Fig. 28).
(29) Loosen cradle engine mounts to allow move-
ment for positioning onto engine locating holes on the
engine. Lower vehicle and position cradle mounts
until the engine is resting on mounts. Tighten
mounts to cradle frame. This will keep mounts from
moving when removing or installing engine and
transmission.
(30) Lower vehicle so the weight ofONLY THE
ENGINE AND TRANSMISSIONis on the cradle.
(31) Remove right engine mount assembly and left
transmission mount through bolt. Refer to Engine
Mounts Section of this Group.
(32) Raise vehicle slowly. It may be necessary to
move the engine/transmission assembly on the cradle
to allow for removal around body flanges.INSTALLATION
(1) Position engine and transmission assembly
under vehicle and slowly lower the vehicle over the
engine and transmission. It may be necessary to
move the engine/transmission assembly with the cra-
dle for clearance around body flanges.
(2) Align engine and transmission mounts to
attaching points. Install mounting bolts at the right
engine and left transmission mounts. Refer to proce-
dures outlined in this section.
(3) Slowly raise vehicle enough to remove the
engine dolly and cradle Special Tools 6135, 6710,
6848 and 6909.
(4) Remove Special tools 6912 and install bending
braces.
(5) Lower vehicle. Install generator and wiring
harness.
(6) Connect wiring harness on the front of the
engine.
(7) Install Air Conditioning Compressor.
(8) Install power steering pump and bracket and
accessory drive belt. Refer to Accessory drive Section
Located in group 7 for installation procedure.
(9) Raise vehicle and install axle shafts. Refer to
Group 3, Differential and Driveline for procedure.
(10) Install transmission and engine mount and
bracket assemblies. Refer to Engine Mounts section
of this Group.
(11)(AWD equipped)Install propeller shaft to
power transfer unit. Refer to Group 3, Differential
and Driveline for procedure.
(12) Connect exhaust system to manifold. Refer to
Group 11, Exhaust System and Intake Manifold for
procedure and torque specifications.
(13) Install crossmember cradle plate (Fig. 27).
(14) Install left and right inner splash shields.
(15) Connect automatic transmission shifter link-
age. Refer to Group 21, Transmission for procedures.
(16) Lower vehicle and connect fuel line and
heater hoses. Remove plugs from rear heater hoses
and install, if equipped.
(17) Install ground straps. Connect engine and
throttle body connections and harnesses.
(18) Connect throttle body linkage. Refer to Group
14, Fuel System for procedure.
(19) Install radiator and fan module assembly.
Install radiator hoses. Fill cooling system. See Group
7 for filling procedure.
(20) Install battery tray, battery and cover.
(21) Install air cleaner and hoses.
(22) Install oil filter. Fill engine crankcase with
proper oil to correct level.
(23) Start engine and run until operating temper-
ature is reached.
(24) Adjust transmission linkage, if necessary.
Fig. 28 Positioning Engine Cradle Support Post
MountsÐTypical
NS3.3/3.8L ENGINE 9 - 105
REMOVAL AND INSTALLATION (Continued)

2.5L VM DIESEL
INDEX
page page
GENERAL INFORMATION
ENGINE IDENTIFICATION................ 41
GENERAL SPECIFICATION............... 40
DESCRIPTION AND OPERATION
LUBRICATION SYSTEM.................. 41
DIAGNOSIS AND TESTING
ENGINE DIAGNOSISÐMECHANICAL....... 44
ENGINE DIAGNOSISÐPERFORMANCE..... 43
HYDRAULIC TAPPETS................... 47
SERVICE PROCEDURES
CHANGING ENGINE OIL AND FILTER....... 47
CHECKING OIL LEVEL................... 47
CRANKSHAFT END PLAY................ 50
FITTING PISTON RING.................. 50
TIMING PROCEDURE................... 49
VALVE AND SEAT REFACING............. 49
REMOVAL AND INSTALLATION
CAMSHAFT........................... 62
CAMSHAFT BEARINGS.................. 63
CRANKSHAFT MAIN BEARINGS........... 63
CRANKSHAFTÐREMOVAL............... 72
CYLINDER HEAD....................... 55
CYLINDER HEAD COVER................ 54
CYLINDER LINER...................... 72
ENGINE ASSEMBLY..................... 53
ENGINE MOUNTÐFRONT................ 51
ENGINE MOUNTÐREAR................. 52
ENGINE MOUNTÐRIGHT................ 51
HYDRAULIC TAPPETS................... 60
INJECTION PUMP...................... 61
MOUNTÐLEFT SIDE.................... 51
OIL FILTER ADAPTER AND OIL COOLER.... 68
OILPAN .............................. 66OIL PUMP............................ 67
OIL PUMP PRESSURE RELIEF VALVE...... 67
PISTONS AND CONNECTING ROD......... 68
REAR CRANKSHAFT OIL SEAL............ 72
ROCKER ARMS AND PUSH RODS......... 54
TIMING GEAR COVER................... 61
TIMING GEAR COVER OIL SEAL........... 61
VACUUM PUMP........................ 68
VALVE SPRINGSÐCYLINDER HEAD NOT
REMOVED.......................... 55
VALVES AND VALVE SPRINGSÐHEAD OFF . . 60
VIBRATION DAMPER.................... 61
DISASSEMBLY AND ASSEMBLY
HYDRAULIC TAPPETS................... 73
CLEANING AND INSPECTION
CRANKSHAFT......................... 77
CRANKSHAFT MAIN BEARING............ 77
CYLINDER HEAD....................... 75
CYLINDER HEAD COVERS............... 74
CYLINDER LINER...................... 78
HYDRAULIC TAPPETS................... 76
OILPAN .............................. 78
OIL PUMP............................ 76
PISTON AND CONNECTING ROD.......... 76
ROCKER ARMS AND PUSH RODS......... 74
TIMING GEAR COVER................... 75
VALVES AND VALVE SPRINGS............ 76
SPECIFICATIONS
2.5L VM DIESEL........................ 78
TORQUE............................. 80
SPECIAL TOOLS
2.5L VM DIESEL........................ 81
GENERAL INFORMATION
GENERAL SPECIFICATION
Type ........................425CLIEE (36B)
Displacement...................2.5L (2499 cc)
Bore.............................92.00 mm
Stroke............................94.00 mm
Compression Ratio....................20.95:1
Vacuum at Idle..........600mm/Hg (23.6 In/Hg)
Thermostat Opening................80ÉC62ÉC
Generator Rating............Bosch 50/120 Amp
Cooling System Capacity..............9.5Liter
Power Steering Capacity.............0.75 LiterType ........................425CLIEE (36B)
Engine Oil Capacity.....6.5Liters With Oil Filter
Change
Timing System . Pushrod Operated Overhead valves,
With Gear-Driven Camshaft.
Air Intake........................DryFilter
Fuel Feed...........Vacuum Pump Incorporated
in Injection Pump.
Fuel System.............Indirect Fuel Injection
(Precombustion Chamber)
Combustion Cycle....................4Stroke
Cooling System..................Water Cooled
Injection Pump.......Rotary Pump Electronically
Controlled.
9 - 40 ENGINENS/GS

DIAGNOSIS AND TESTING
ENGINE DIAGNOSISÐPERFORMANCE
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT
CRANK OR CRANKS
SLOWLY1. Starting motor operating, but not cranking the
engine.1. Remove the starter motor. Check for broken
flywheel teeth or a broken starter motor spring.
2. Crankshaft rotation restricted. 2. Rotate the engine to check for rotational
resistance.
3. Starting circuit connections loose or corroded. 3. Clean and tighten connections.
4. Neutral safety or starter relay inoperative. 4. Check starter relay supply voltage and proper
operation of neutral safety switch (if equipped).
Replace defective parts.
5. Battery charge low. 5. Check Battery voltage. Replace battery if a
charge cannot be held.
6. No voltage to starter solenoid. 6. Check voltage to solenoid. If necessary, replace
the solenoid.
7. Solenoid or starter motor inoperative. 7. Replace starter motor.
ENGINE CRANKS, BUT
WILL NOT START, NO
SMOKE1. No fuel in supply tank. 1. Fill fuel supply.
2. Electrical fuel shutdown solenoid not operating. 2. Check for loose wires and verify that the fuel
shutdown solenoid is functioning. Check for fault
codes in the ECU.
3. Fuel injection system defective: Cranking speed
sensor. Loose connection between ECU and
harness. No power supply to the ECU. Loose
connection between injection pump and harness.3. Check for fault codes at ECU. Refer to Group 14,
Fuel System for repairs procedures.
4. Air intake or exhaust plugged. 4. Remove the obstruction.
5. Fuel filter plugged. 5. Drain fuel/water separator and replace fuel filter.
6. Excessive fuel inlet restriction. 6. Check for restriction. Correct cause.
7. Injection pump not getting fuel or fuel is aerated. 7. Check fuel flow/bleed fuel system.
8. One or more injectors worn or not operating
properly.8. Check/replace bad or improperly operating
injectors.
9. Camshaft out of time. 9. Check/correct timing chain sprocket alignment.
ENGINE HARD TO
START, OR WILL NOT
START, SMOKE FROM
EXHAUST1. Incorrect starting procedure. 1. The fuel shutoff solenoid control must be in the
run position. Ensure the proper procedure is being
used.
2. Cranking speed to slow. 2. Check the battery, starter motor and look for
loose or corroded wiring connections.
3. Cylinder head heater plugs defective. 3. Verify system is working. Verify connection
between heater plug relay and ECU. Repair/replace
inoperative parts.
4. Insufficient intake air 4. Inspect or replace air filter and check for
obstruction in air supply.
5. Air in fuel system or the fuel supply is
inadequate.5. Check the fuel flow through the filter and bleed
system. Locate and eliminate the air source.
6. Contaminated fuel. 6. Verify by operating the engine with clean fuel
from a temporary tank. Check for the presence of
gasoline. Drain and flush fuel supply tank. Replace
fuel/water separator filter.
7. Fuel screen plugged. 7. Check fuel screen.
8. One or more injectors worn or not operating
properly.8. Check/replace improperly operating injectors.
9. Injector pump out of time. 9. Check pump timing. Refer to Group 14, Fuel
System for procedure.
10. Engine compression low. 10. Check compression to identify the problem.
11. Fuel injection system defective. 11. Vacuum modulator defective causing EGR to
open in cold condition. Check for fault codes in the
ECU.
NS/GSENGINE 9 - 43

ENGINE DIAGNOSISÐMECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
LUBRICATING OIL PRESSURE
LOW1. Low oil level. 1a. Check and fill with clean engine
oil.
1b. Check for severe external oil
leaks that could reduce the
pressure.
2. Oil viscosity thin, diluted, or
wrong specification.2. Verify the correct oil is being
used. Check for oil dilution.
3. Improperly operating pressure
switch/gauge3. Verify the pressure switch is
functioning correctly. If not, replace
switch/gauge.
4. Relief valve stuck open. 4. Check/replace valve.
5. Plugged oil filter. 5. Change oil filter. Oil filter change
interval may need to be revised.
6. Oil cooler was replaced, shipping
plugs left in cooler.6. Check/removed shipping plugs.
7. Worn oil pump. 7. Check/replace oil pump.
8. Suction tube loose or seal
leaking.8. Check and replace seal.
9. Worn bearing or wrong bearing
installed.9. Inspect and replace connecting
rod or main bearings. check and
replace piston cooling oil jet.
10. Oil jets under piston loose or
bad fit.10. Check oil jets position.
LUBRICATING OIL LOSS 1. External oil leaks. 1. Visually inspect for oil leaks.
Repair as required.
2. Crankcase being overfilled. 2. Verify that the correct dipstick is
being used.
3. Incorrect oil specification or
viscosity.3a. Make sure the correct oil is
being used.
3b. Look for reduced viscosity from
dilution with fuel.
3c. Review/reduce the oil change
intervals.
4. Oil cooler leak. 4. Check and replace the oil cooler.
5. High blow-by forcing oil out the
breather.5. Check the breather tube area for
signs of oil loss.
9 - 44 ENGINENS/GS
DIAGNOSIS AND TESTING (Continued)

HYDRAULIC TAPPETS
Before disassembling any part of the engine to cor-
rect tappet noise, check the oil pressure. If vehicle
has no oil pressure gauge, install a reliable gauge at
the pressure sending unit. The pressure should be
between 3.5 bars to 5.0 bars at 4000 RPM.
Check the oil level after the engine reaches normal
operating temperature. Allow 5 minutes to stabilize
oil level, check dipstick. The oil level in the pan
should never be above the FULL mark or below the
ADD OIL mark on dipstick. Either of these 2 condi-
tions could be responsible for noisy tappets.
OIL LEVEL HIGH
If oil level is above the FULL mark, it is possible
for the connecting rods to dip into the oil. With the
engine running, this condition could create foam in
the oil pan. Foam in oil pan would be fed to the
hydraulic tappets by the oil pump causing them to
lose length and allow valves to seat noisily.
OIL LEVEL LOW
Low oil level may allow oil pump to take in air.
When air is fed to the tappets, they lose length which
allows valves to seat noisily. Any leaks on intake side
of oil pump through which air can be drawn will cre-
ate the same tappet action. Check the lubrication
system from the intake strainer to the pump cover,
including the relief valve retainer cap. When tappet
noise is due to aeration, it may be intermittent or
constant, and usually more than 1 tappet will be
noisy. When oil level and leaks have been corrected,
operate the engine at fast idle. Run engine for a suf-
ficient time to allow all of the air inside the tappets
to be bled out.
TAPPET NOISE DIAGNOSIS
(1) To determine source of tappet noise, operate
engine at idle with cylinder head covers removed.
(2) Feel each valve spring or rocker arm to detect
noisy tappet. The noisy tappet will cause the affected
spring and/or rocker arm to vibrate or feel rough in
operation.
NOTE: Worn valve guides or cocked springs are
sometimes mistaken for noisy tappets. If such is
the case, noise may be dampened by applying side
thrust on the valve spring. If noise is not apprecia-
bly reduced, it can be assumed the noise is in the
tappet. Inspect the rocker arm push rod sockets
and push rod ends for wear.
(3) Valve tappet noise ranges from light noise to a
heavy click. A light noise is usually caused by exces-
sive leak down around the unit plunger or by the
plunger partially sticking in the tappet body cylinder.
The tappet should be replaced. A heavy click iscaused by a tappet check valve not seating or by for-
eign particles becoming wedged between the plunger
and the tappet body. This will cause the plunger to
stick in the down position. This heavy click will be
accompanied by excessive clearance between the
valve stem and rocker arm as valve closes. In either
case, tappet assembly should be removed for inspec-
tion and cleaning.
(4) The valve train generates a noise very much
like a light tappet noise during normal operation.
Care must be taken to ensure that tappets are mak-
ing the noise. In general, if more than one tappet
seems to be noisy, its probably not the tappets.
SERVICE PROCEDURES
CHECKING OIL LEVEL
To assure proper engine lubrication, the engine oil
must be maintained at the correct level. Check the
oil level at regular intervals, such as every fuel stop.
The best time to check the oil level is about 5 min-
utes after a fully warmed-up engine is shut off, or
before starting the vehicle after it has sat overnight.
Checking the oil while the vehicle is on level
ground, will improve the accuracy of the oil level
readings (Fig. 4).
CHANGING ENGINE OIL AND FILTER
Change engine oil and filter at mileage and time
intervals described in the Maintenance Schedule.
Fig. 4 Checking Engine Oil
NS/GSENGINE 9 - 47
DIAGNOSIS AND TESTING (Continued)