1993 DODGE TRUCK Service Repair Manual

9
- 4 ENGINES
•

RN861
Fig. 3 Clearance Measurement
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 61 Nnn (45 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:
• Drilling out worn or damaged threads. • Tapping the hole with a special Heli-Coil Tap, or
equivalent.
• Installing 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.

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 en­

gine.

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 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 Group 0, Lubrica­
tion and Maintenance). (15) Connect the negative cable to the battery.
(16) Start the engine and check for any leaks.

•

ENGINES
9 - S
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 Diagnosis—Performance chart
and the Service Diagnosis—Mechanical chart for pos­
sible causes and corrections of malfunctions. Refer to
Group 14, Fuel System for the fuel system diagnosis.

SERWIGE DIAGNOSIS (GASOLINE ENGINES)
-
PERFORMANCE
CONDITION

POSSIBLE
CAUSES
CORRECTION

ENGINE
WILL
NOT
START
1.
Weak
battery.

2.
Corroded
or
loose
battery
connections.

3.
Faulty
starter.

4.
Moisture
on
ignition wires and distributor
cap.

5.
Faulty
ignition
cables.

6.
Faulty
coil
or
control
unit.

7.
Incorrect
spark
plug
gap.
8.
Incorrect
ignition timing.
9.
Dirt
or
water
in
fuel
system.

10.
Faulty
fuel
pump.
1.
Test
battery
specific
gravity.
Charge
or
replace
as
necessary.

2. Clean
and
tighten
battery
connections.
Apply
a
coat
of light
mineral
grease
to
the terminals.
3. Refer to
Group
8A, Battery/Starter/Charging
System
Diagnostics.

4. Wipe
wires
and
cap
clean
and
dry.
5.
Replace
any
cracked
or
shorted
cables.

6.
Test
and
replace,
if
necessary
(refer
to
Group
8D,
Ignition
System).

7.
Set
gap
(refer
to
Group
8D, Ignition
System).

8. Refer to
Group
8D, Ignition
System.

9. Clean
system
and
replace
fuel
filter.

10. Install new
fuel
pump
(refer
to
Group
14,
Fuel
System).

ENGINE
STALLS
OR

ROUGH
IDLE
1.
Idle
speed
set
too
low.
2.
Idle
mixture
too
lean
or
too
rich.
3. Leak in
intake
manifold.
4. Worn or burned distributor
rotor.

5.
Incorrect
ignition wiring.
6.
Faulty
coil.

7.
EGR
valve leaking.
1.
Refer to
Group
14,
Fuel
System.

2. Refer to
Group
14,
Fuel
System.

3.
Inspect
intake
manifold
gasket
and
vacuum
hoses.
Replace,
if
necessary
(refer
to
Group
11,
Exhaust
System
&
Intake

Manifold).

4.
Install new distributor
rotor.

5. Install
correct
wiring.
6.
Test
and
replace,
if
necessary
(refer
to
Group
8D,
Ignition
System).

7.
Test
and
replace,
if
necessary
(refer
to
Group
25,
Emissions
Control
System).

J9309-105

9
- 6
ENGINES
•

SERVICE DIAGNOSIS (GASOLINE ENGINES)
•
PERFORMANCE (CONT.)

1
CONDITION

POSSIBLE
CAUSES
^
CORRECTION

1
ENGINE
LOSS
OF
POWER
1.
Incorrect ignition timing.
2. Worn or burned distributor
rotor.
3. Worn distributor shaft.

4.
Dirty
or
incorrectly
gapped
spark
plugs.

5.
Dirt
or
water
in
fuel
system.

6.
Faulty
fuel
pump.

7.
Incorrect valve timing.
8.
Blown
cylinder head
gasket.

9.
Low
compression.

10.
Burned,
warped or
pitted
valves.

11.
Plugged
or
restricted
exhaust
system.

12. Faulty ignition
cables.

13. Faulty coil.
1.
Refer
to
Group
8D, Ignition
System.

2. install new distributor
rotor.

3.
Remove
and
repair
distributor
(refer
to
Group
8D, Ignition
System).

4.
Clean
plugs
and
set gap
(refer
to
Group
8D, Ignition
System).

5. Clean
system
and replace
fuel
filter.

6. Install new
fuel
pump.

7.
Correct
valve
timing.
8. Install new cylinder head
gasket.

9.
Test
compression
of
each
cylinder.

10.
Install new
valves.
11.
Install new
parts,
as
necessary.

12.
Replace
any cracked or
shorted
cables.

13.
Test
and
replace,
as
necessary
(refer
to
Group
8D, Ignition
System).

ENGINE
MISSES
ON

ACCELERATION
1.
Dirty
or
gap set
too
wide
in spark
plug.
2. Incorrect ignition timing.
3.
Dirt
in
fuel
system.

4.
Burned,
warped or
pitted
valves.
5. Faulty coil.
1.
Clean spark
plugs
and set gap
(refer
to
Group
8D, Ignition

System).

2. Refer to
Group
8D, Ignition
System.

3. Clean
fuel
system.

4.
Install new
valves.

5.
Test
and
replace,
if
necessary,
(refer
to
Group
8D, Ignition
System).

ENGINE
MISSES
AT HIGH

SPEED
1.
Dirty
or
gap set too
wide
in spark
plug.
2. Worn distributor shaft.
3. Worn or burned distributor
rotor.

4. Faulty
coil.

5. Incorrect ignition timing.
6.
Dirty
injector
in
throttle
body.
7.
Dirt
or
water
in
fuel
system.
1.
Clean
spark
plugs
and
set gap
(refer
to
Group
8D, Ignition

System).

2.
Remove
and
repair
distributor
(refer
to
Group
8D,
Ignition
System).

3. Install new distributor
rotor.

4.
Test
and replace,
as
necessary
(refer
to
Group
8D, Ignition
System).

5.
Refer
to
Group
8D, Ignition
System.

6.
Clean
injector.

7.
Clean
system
and replace
fuel
filter.

J9309-106

•

ENGINES
9 - 7 SERVICE DIAGNOSIS (GASOLINE ENGINES) - MECHANICAL

CONDITION
PSSSI1LI
CAUSIS
CORRECTION

NOISY
VALVES
1. High
or
low oil
level
in

crankcase.

2. Thin or
diluted
oil.

3.
Low
oil
pressure.
4.
Dirt
in
tappets/lash
adjusters.

5. Bent
push
rods.
6. Worn rocker arms.
7.
Worn
tappets/lash
adjusters.

8.
Worn
valve
guides.

9.
Excessive
runout
of
valve
seats
on
valve
faces.
1.
Check
for
correct oil
level
(refer
to
Group
0,
Lubrication and
Maintenance).
2. Change oil
(refer
to Group
0,
Lubrication and Maintenance).
3. Check engine oil level.
4. Clean hydraulic tappets/hydraulic lash adjusters.
5. Install new
push
rods.
6. Inspect oil supply to rocker arms.
7. Install new hydraulic tappets/hydraulic lash adjusters. 8. Ream and install new valves
with
oversize stems.
9. Grind valve seats and valves.

CONNECTING
ROD
NOISE
1.
Insufficient oil supply.

2.
Low oil
pressure.

3.
Thin
or
diluted
oil.
4.
Excessive
bearing
clearance.
5. Connecting rod
journal
out-of- round.
6. Misaligned connecting rods.
1.
Check engine oil
level
(refer
to Group
0,
Lubrication and
Maintenance).
2. Check engine oil level. Inspect oil pump
relief
valve and spring.
3. Change oil to correct
viscosity.

4. Measure bearings for correct clearance. Repair as necessary, 5. Replace crankshaft or grind journals.

6.
Replace
bent
connecting rods.

MAIN
BEARING
NOISE
1.
Insufficient oil supply.
2 Low
oil
pressure.
3. Thin or
diluted
oil.
4.
Excessive
bearing clearance. 5.
Excessive
end play.
6. Crankshaft
journal
out-of-round, worn,
7.
Loose
flywheel
or
torque

converter.
1.
Check engine oil
level
(refer
to Group
0,
Lubrication and
Maintenance).
2. Check engine oil level. Inspect oil pump
relief
valve and spring.
3. Change oil to correct
viscosity.

4. Measure bearings for correct clearance. Repair as necessary. 5. Check No.
3
main bearing for
wear
on flanges.
6. Grind journals
or
replace crankshaft.
7. Tighten to correct torque.

OIL
PRESSURE
DROP
1.
Low oil level.
2. Faulty oil pressure sending
unit.

3. Low
oil
pressure.
4.
Clogged
oil
filter.

5 Worn parts in
oil
pump.
6. Thin or
diluted
oil.
7.
Excessive
bearing clearance. 8.
Oil
pump
relief
valve stuck.
9. Oil pump suction
tube
loose,
bent
or cracked.

10.
Oil pump cover warped
or
cracked.
1.
Check engine oil level.
2. Install new sending
unit.

3. Check sending
unit
and check main bearing oil clearance.
4. Install new oil
filter.

5. Replace worn parts or pump. 6. Change oil to correct
viscosity.

7. Measure bearings for correct clearance.
8. Remove valve and inspect, clean and install. 9. Remove oil pan and install new tube,
if
necessary.
10. Install new oil pump.

OIL
LEAKS
1.
Misaligned or
deteriorated

gaskets.
2.
Loose
fastener, broken
or
porous
metal
part.
1. Replace the gasket.
2. Tighten,
repair
or replace the
part.

OIL
PUMPING
AT
RINGS;
SPARK
PLUGS
FOULING
1.
Worn, scuffed
or broken
rings.
2. Carbon in oil ring
slot.

3.
Rings
fitted
too
tightly
in grooves.
4. Worn valve guides.
5. Leaking
intake
gasket.
6. Leaking valve guide
seals.

7. Dislodged valve guide
seals.
1.
Hone cylinder bores and install new rings.
2. Install new rings.
3. Remove the rings. Check
grooves.
If
grooves
are not proper width, replace piston.
4. Ream guides and replace valves
with
oversize valves and
seals.

5. Replace gasket and tighten
intake
manifold
to
proper torque.
6. Replace
seals.

7. Seat
valve guide
seals
or
replace, as needed.
J9209-58

9
- 8
ENGINES

• SERVICE DIAGNOSIS (DIESEL ENGINE) - PERFORMANCE

CONDITION
POSSIBLE
CAUSES
COtiECTION

ENGINE
WILL
NOT

CRANK
OR
CRANKS

SLOWLY
Starting
motor operating, but
not cranking the engine.

Crankshaft
rotation restricted.

Starting
circuit
connections
loose
or corroded.
Neutral safety switch or starter
relay inoperative.
Battery charge low.

No
voltage to starter
solenoid.

Solenoid
or starting motor inoperative.
Remove
the starter motor. Check for broken flywheel
teeth
or

a
broken starting motor
spring.

Rotate the engine to check for rotational resistance.

Clean
and tighten
connections.

Check
starter relay for
supply
voltage and proper operation of neutral safety. Replace defective parts.

Check
battery voltage. Replace battery if a charge cannot be
held.

Check
voltage to
solenoid.
If
necessary,
replace the
solenoid.

Replace
starter motor.

ENGINE
CRANKS,

BUT
WILL
NOT

START—NO
SMOKE
FROM
EXHAUST
No
fuel
in supply tank.
Electrical
fuel
shutdown not

open.

Air
intake or exhaust
plugged.

Fuel
filter
plugged.

Injection pump not getting
fuel

or
fuel
is aerated.

Worn
or inoperative injection
pump.

Internal pump timing incorrect.

Camshaft
out of time.
Fill
fuel
supply.

Check
for
loose
wires and verify that the valve is functioning.
Check
to be sure manual shutoff lever is in the run position.

Remove
the obstruction.

Drain
fuel/water separator and replace
fuel
filter.

Check
fuel
flow/bleed
fuel
system.

Visually
check
fuel
delivery with an externally connected injector to one of the pump outlets. Replace the pump if
fuel

is
not being delivered.
Time the pump
(refer
to Group 14, Fuel
System).

Check/correct
gear train timing alignment.

ENGINE
HARD
TO

START,
OR
WILL
NOT
START—SMOKE

FROM
EXHAUST
Incorrect starting procedure.

Cranking
speed too
slow.

Cold
starting
aids
not working

or
are needed.
Intake heater
system
not

working.

Insufficient intake air.

Air
in the
fuel
system
or the

fuel
supply is inadequate. The manual
fuel
shutoff control must be in the run position.
(a) Verify that the
transmission
is not
engaged.

(b) Check the battery, starting motor and look for
loose
or

corroded
wiring
connections.

(c) Rotate the engine with a barring tool
(Snap-On
Tool
SP371,
MTE
No. 3377462, or equivalent) to check for internal rotational resistance.
Verify the
aids
are operating. Repair/replace inoperative
parts.

Verify
system
is working. Repair/replace inoperative parts.

Inspect
or replace
filter
and check for
obstructions
to the air

supply
tube.

Check
the flow through the
filter
and bleed the
system.
Locate

and
eliminate the air source. J9109-232

•

ENGINES
9 - 9 SERVICE DIAGNOSIS (DIESEL ENGINE) • PERFORMANCE (CONT.)

CONDITION
POSSIBLE
CAUSES
CORRECTION

ENGINE
HARD
TO

START,
OR
WILL

NOT
START—SMOKE

FROM
EXHAUST

(Cont'd)
Fuel pump Inoperative.
Injection pump
throttle
linkage

loose
or
damaged.

Contaminated
fuel.

Worn
or inoperative injection
pump.

Injection pump out of time.

Valves
incorrectly adjusted.

One
or more injectors worn or not operating properly.
Disconnect
fuel
line and verify
fuel
delivery. If needed replace

pump.

Visually
check the linkage. Tighten/replace linkage.
Verify by operating the engine with clean
fuel
from a temporary tank. Check for presence of
gasoline.
Drain and

flush
fuel
supply tanks.
Replace
fuel/water separator
filter.

Visually
check
fuel
delivery with an externally connected injector to one of the pump outlets. Replace the pump if
fuel
is
not being delivered.

Check/time
the pump
(refer
to Group 14, Fuel
System).

Adjust
valves.
Check/replace
bad improperly operating injectors.

ENGINE
STARTS,

BUT
WILL
NOT

KEEP
RUNNING
Idle speed too low for the

accessories.

Intake air or exhaust
system

restricted.

Air
in the
fuel
system
or the

fuel
supply is inadequate.
Fuel waxing due to extremely

cold
weather.

Contaminated
fuel.
Adjust
the idle
speed.

Visually
check for exhaust restriction and inspect the air intake.
Repair/replace restricting parts.

Check
the flow through the
filter
and bleed the
system.
Locate

and
eliminate the air source.
Verify by inspecting the
fuel
filter.
Clean the
system
and use
climatized fuel. Replace fuel/water separator
filter.
Check
fuel

heater for proper operation.
Verify by operating the engine with clean
fuel
from a temporary

supply
tank. Check for presence of
gasoline.
Replace fuel/water

separator
filter.

SURGING
(SPEED

CHANGE)
If the condition
occurs
at idle,
the idle speed is set too low for
the
accessories.

High
pressure
fuel
leak.

One
or more injectors worn or not operating properly.
Improperly operating injection

pump.
Adjust
the idle.

Inspect/correct
leaks in the high pressure lines. Fittings and
delivery valve
sealing
washers.

Check/replace
the inoperative injectors.

Replace
the injection pump.

ROUGH
IDLE

(IRREGULARLY
FIRING

OR
ENGINE
SHAKING)
Cold
engine.
Idle speed too low for the

accessories.

Engine
mounts
damaged
or
loose.
Refer to troubleshooting
logic
for intake manifold heater
system

(see
Group 11,
Exhaust
System
& Intake Manifold)

Adjust
idle
speed.

Repair
or replace mounts. J9109-233

9
- 10
ENGINES
— _
•
CONDITION

possmu
CLOSES
CORRECTION

ROUGH
IDLE

(IRREGULARLY
FIRING

OR
ENGINE
SHAKING)
(Cont'd)
High
pressure
fuel
leaks.

Air In the
fuel
system.
Correct leaks in the high pressure lines, fittings or
delivery

valves.

Bleed the
fuel
system and
eliminate
the source of the air.

Sticking
needle
valve
in an
injector.
Check and replace the
injector
with
the sticking
needle
valve.

ENGINE
RUNS
ROUGH

OR
MISFIRING
Fuel
injection
lines
leaking.

Correct leaks in the high pressure lines, fittings,
injector
sealing

washers
or
delivery
valves.
Air in the
fuel
or the
fuel
supply
is
inadequate.
Check the flow through the
filter
and bleed the system. Locate
and
eliminate
the air source.

Contaminated
fuel.
Verify
by operating the engine
with
clean
fuel
from a temporary

supply
tank. Check for presence of gasoline. Replace
fuel/water

separator
filter.

Incorrect
valve
adjustment.
Check for a
bent
push rod and adjust valves. Replace push rod,
if necessary.

Injection
pump
timing
incorrect.
Check/time pump
(refer
to Group 14,
Fuel
System).

Improperly
operating
injectors.
Replace inoperative injectors.
Defective
injection
pump

(delivery
valves).
Replace
injection
pump.

Camshaft
out of
time.
Check/correct gear
train
timing alignment.

Damaged
camshaft or
tappets.
Inspect camshaft valve
lift.
Replace camshaft and tappets.

ENGINE
RPM WILL NOT

REACH
RATED
SPEED
Engine
overloaded.

Verify
high
idle
speed
without
load. Investigate operation to be
sure correct gear is being used.

Improperly
operating
tachometer.
Verify
engine speed
with
hand tachometer—correct as required.

Throttle
linkage
worn
or
incorrectly
adjusted.
Adjust linkage for stop-to-stop
fuel
control
lever
travel.
Replace
linkage if necessary.
Partially
engaged
mechanical

shutdown
lever.
Adjust and place shutdown
lever
in the run position.

Inadequate
fuel
supply. Check the
fuel
flow through the system to locate the reason for
inadequate
fuel
supply—correct as required.

Improperly
operating
injection

pump.
Replace
injection
pump.

LOW
POWER
Fuel
control
lever
not
moving
to

full
throttle.
Check/correct for stop-to-stop
travel.

Mechanical/shutdown
lever
partially
engaged.
Check to see if the shutdown
lever
is in run position.

High
oil
level.
Check/correct oil level.

Engine
overloaded.
Check for added loading from accessories or driven units, brakes

dragging
and
other
changes in vehicle loading. Repair/replace as
needed.
J9109-264
SERVICE
DIAGNOSIS (DIESEL ENGINE)
•
PERFORMANCE (CONT.)

•

ENGINES
9 - 11 SERVICE DIAGNOSIS (DIESEL ENGINE) - PERFORMANCE (CONT.)

CONDITION
POSSIBLE
CAUSES
CORRECTION

LOW
POWER
(Cont'd)
SJow
throttle
response, leaking
air
fuel
control
tube
or
improperly
operating
control

in the pump. Tighten the fittings. Replace the pump if the controls are not
functioning.
Incorrect
external
injection

pump
timing. Verify
that
injection pump timing marks are aligned (see Group
14, Fuel System).
Inadequate intake air flow. Inspect/replace air cleaner element. Look for other restrictions.

High
pressure
fuel
leak. Inspect/correct leaks in the high pressure lines, fittings
injector

sealing
washers or delivery valve
seals.

Inadequate
fuel
supply.
Check
the flow through the
filter
to locate the source of the
restriction.

High
fuel
temperature. Verify
that
fuel
heater is off during warm weather. Check for a
restricted
fuel
drain manifold. Repair/replace as needed.

Poor
quality
fuel
or
fuel

contaminated
with
gasoline. Verify by operating from a temporary tank
with
good
fuel.

Check
for presence of
gasoline.
Replace
fuel/water
separator

filter.

Air
leak between the turbo- charger and the intake manifold. Check/correct leaks in the air crossover tube,
hoses,
gaskets,

and
around mounting capscrews or through holes in the manifold
cover.

Exhaust
leak at the manifold
or turbocharger. Check/correct leaks in the manifold or turbocharger
gaskets.

If manifold is cracked, replace manifold.
Improperly operating turbo-
charger. Inspect/replace turbocharger.
Valve clearance incorrect.
Check/adjust
valves.
Injection pump improperly
operating. Check/time pump
(refer
to Group 14, Fuel System).

Worn
or improperly operating injectors. Check/replace injectors.
Improperly operating injection

pump.
Replace
injection pump.

Excessive
exhaust restriction. Check/correct the restriction in the exhaust system.

EXCESSIVE
EXHAUST

SMOKE
Engine
running too cold
(white

smoke).
Refer to troubleshooting logic for coolant
temperature
below
normal
(refer
to Group 7,
Cooling
System).
Inspect intake
manifold heater/KSB valve for proper operation.
Inadequate intake air.
Inspect/change
air cleaner. Look for other restriction.

Air
leak between turbocharger

and
intake manifold. Check/correct leaks in the air crossover tube,
hoses,
gaskets,

mounting capscrews or through holes in the manifold cover.

Exhaust
leak at the manifold
or turbocharger. Check/correct leaks in the manifold or turbocharger
gaskets.

If cracked replace manifold.
Improperly operating
turbocharger. Inspect/replace turbocharger.
J9209-57