1993 DODGE TRUCK cooling

8D
- 16
IGNITION
SYSTEMS

• other operating conditions are causing engine over­
heating. (The heat range rating refers to the operat­
ing temperature of a particular type spark plug.
Spark plugs are designed to operate within specific
temperature ranges. This depends upon the thickness and length of the center electrodes porcelain insula­
tor.)

GROUND

ELECTRODE
CENTER

ELECTRODE

DISSOLVED

J908D-14 Fig. 26 Preignition Damage

SPARK
PLUG
OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
27).
The increase in electrode gap will be consider­
ably in excess of 0.001 inch per 1000 miles of opera­
tion. This suggests that a plug with a cooler heat
range rating should be used. Over advanced ignition
timing, detonation and cooling system malfunctions can also cause spark plug overheating.

BLISTERED

WHITE
OR
J908D-16
Fig. 27 Spark Plug Overheating

SPARK
PLUG
SECONDARY
CABLES
Spark plug heat shields are pressed into the cylin­
der head to surround each spark plug cable boot and spark plug (Fig. 28). These shields protect the spark
plug boots from damage (due to intense engine heat
generated by the exhaust manifolds) and should not be removed. After the spark plug cable has been in­
stalled, the lip of the cable boot should have a small
air gap to the top of the heat shield (Fig. 28).

Fig.
28 Heat
Shields
TESTING

Spark plug cables are sometimes referred to as sec­
ondary ignition cables or secondary wires. The cables
transfer electrical current from the distributor to in­ dividual spark plugs at each cylinder. The spark plug
cables are of nonmetallic construction and have a
built in resistance. The cables provide suppression of radio frequency emissions from the ignition system.
Check the high-tension cable connections for good
contact at the ignition coil, distributor cap towers and spark plugs. Terminals should be fully seated.
The terminals and spark plug covers should be in good condition. Terminals should fit tightly to the ig­
nition coil, distributor cap and spark plugs. The spark plug cover (boot) of the cable should fit tight
around the spark plug insulator. Loose cable connec­
tions can cause corrosion and increase resistance, re­ sulting in shorter cable service life. Clean the high tension cables with a cloth moist­
ened with a nonflammable solvent and wipe dry.
Check for brittle or cracked insulation. When testing secondary cables for damage with an
oscilloscope, follow the instructions of the equipment
manufacturer. If an oscilloscope is not available, spark plug cables
may be tested as follows:

CAUTION:
Do not leave any one
spark
plug
cable

disconnected
for
longer
than
necessary
during test­
ing.
This
may
cause
possible
heat
damage
to the
catalytic converter. Total test
time
must
not exceed
ten
minutes.

With the engine not running, connect one end of a
test probe to a good ground. Start the engine and run the other end of the test probe along the entire length of all spark plug cables. If cables are cracked

8D
- 20
IGNITION
SYSTEMS

•
ENGINE
COOLANT
TEMPERATURE
SENSOR

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV­
ING THE COOLANT TEMPERATURE SENSOR. RE­
FER TO GROUP 7, COOLING.

REMOVAL
(1) Partially drain cooling system. Refer to Group
7, Cooling.

(2)
Disconnect electrical connector from sensor
(Fig. 5). Engines with air conditioning: When removing
the connector from sensor, do not pull directly on
wiring harness. Fabricate an L-shaped hook tool
from a coat hanger (approximately eight inches
long).
Place the hook part of tool under the connector
for removal. The connector is snapped onto the sen­ sor. It is not equipped with a lock type tab.
(3) Remove sensor from intake manifold.
Fig. 5 Coolant Temperature
Sensor—
Typical

INSTALLATION
(1) Install sensor.
(2) Tighten to 7 Nnn (5.5 ft. lbs.) torque.
(3) Connect electrical connector to sensor.
The sensor connector is symmetrical (not indexed).
It can be installed to the sensor in either direction. (4) Replace any lost engine coolant. Refer to Group
7, Cooling System.

DISTRIBUTOR
SERVICE

REMOVAL

CAUTION:
Base
ignition timing
is not
adjustable
on

any
engine. Distributors
do not
have
built
in
centrif­
ugal
or
vacuum assisted advance.
Base
ignition
timing
and
timing advance
are
controlled
by the
powertrain control module
(PCM).
Because
a
con­
ventional timing light can
not be
used
to
adjust
dis­

tributor
position
after
installation, note position
of
distributor before removal.

(1) Disconnect negative battery cable at battery.
(2) Remove distributor cap from distributor (two
screws).
(3) Mark the position of distributor housing in
relationship to engine or dash panel. This is done
to aid in installation. Before distributor is removed, the number one cyl­
inder must be brought to the top dead center (TDC)
firing position. (4) Attach a socket to the Crankshaft Vibration
Damper mounting bolt.
(5) Slowly rotate engine clockwise, as viewed from
front, until indicating mark on crankshaft vibration damper is aligned to 0 degree (TDC) mark on timing
chain cover (Fig. 6).
Fig. 6 Damper-To-Cover Alignment Marks—Typical (6) The distributor rotor should now be aligned to
the CYL. NO. 1 alignment mark (stamped) into the camshaft position sensor (Fig. 7). If not, rotate the
crankshaft through another complete 360 degree

turn.
Note the position of the number one cylinder spark plug cable (on the cap) in relation to rotor. Ro­
tor should now be aligned to this position.
(7) Disconnect camshaft position sensor wiring
harness from main engine wiring harness.
(8) Remove distributor rotor from distributor shaft. (9) Remove distributor holddown clamp bolt and
clamp (Fig. 8). Remove distributor from vehicle.
CAUTION: Do not
crank engine
with
distributor
re­
moved.
Distributor/crankshaft relationship
will
be

lost.

8D
- 22
IGNITION
SYSTEMS

• (1) Disconnect the wiring and secondary cable from
the ignition coil (Figs. 9 or 10).

WARNING:
(3.9L/5.2L/5.9L
LDC-GAS ENGINES)
DO
NOT REMOVE
THE
COIL MOUNTING BRACKET-TO-
CYLINDER HEAD MOUNTING BOLTS.
THE
COIL MOUNTING BRACKET
IS
UNDER ACCESSORY
DRIVE BELT TENSION.
IF
THIS BRACKET
IS TO BE
REMOVED
FOR ANY
REASON,
ALL
BELT TENSION
MUST FIRST
BE
RELIEVED. REFER
TO THE
BELT
SECTION
OF
GROUP
7,
COOLING SYSTEM.

(2) Remove ignition coil from coil mounting
bracket (two bolts).
INSTALLATION (1) Install the ignition coil to coil bracket. If nuts
and bolts are used to secure coil to coil bracket,
tighten to 11 N«m (100 in. lbs.) torque. If the coil mounting bracket has been tapped for coil mounting

bolts,
tighten bolts to 5 N«m (50 in. lbs.) torque.
(2) Connect all wiring to ignition coil.

INTAKE MANIFOLD CHARGE
AIR
TEMPERATURE

SENSOR

REMOVAL The charge air temperature sensor is located in
right-front side of intake manifold (Figs. 11 or 12).
Fig.
11
Sensor
Location—3.9L Engine—Typical
(1) Disconnect electrical connector at sensor (Figs.
11 or 12).
(2) Remove sensor from intake manifold.
INSTALLATION (1) Install sensor to intake manifold. (2) Tighten the sensor to 13 N-m (10 ft. lbs.)
torque. (3) Install electrical connector.
Fig.
12
Sensor
Location—5.2L/5.9L

Engines—Typical
MANIFOLD ABSOLUTE
PRESSURE
(MAP)
SENSOR

For removal and installation, refer to Manifold Ab­
solute Pressure Sensor in group 14, Fuel Systems.

OXYGEN
(02)
SENSOR
For diagnostics and removal/installation proce­

dures,
refer to Group 14, Fuel Systems, in this man­

ual.
POWERTRAIN CONTROL MODULE
(PCM)
REMOVAL The PCM is located in the engine compartment be­
hind the battery and under the left front fender (Fig.

13).
DATA
UNK CONTROL
CONNECTOR MODULE
J9314-164

Fig.
13 PCM Location—Typical (1) Disconnect negative battery cable at battery.
(2) Disconnect positive battery cable at battery.
(3) Remove battery holddown clamps and remove
battery.
(4) Remove 60-way electrical connector from PCM.
(5) Remove the three PCM mounting bolts (Fig.

14).

9
- 2
ENGINES

rial surrounds each mounting hole. Excess material
can easily be wiped off. Components should be
torqued in place within 15 minutes. The use of a lo­ cating dowel is recommended during assembly to pre­
vent smearing the material off location.

ENGINE PERFORMANCE
To provide best vehicle performance and lowest ve­
hicle emissions, it is most important that the tune-up
be done accurately. Use the specifications listed on
the Vehicle Emission Control Information label found on the engine compartment hood.
(1) Test cranking amperage draw (refer to Group

8B,
Battery/Starter/Generator Service for the proper
procedures).
(2) Tighten the intake manifold bolts (refer to
Group 11, Exhaust System and Intake Manifold for
the proper specifications). (3) Perform cylinder compression test:
(a) Check engine oil level and add oil, if neces­
sary.
(b) Drive the vehicle until engine reaches normal
operating temperature. (c) Select a route free from traffic and other
forms of congestion, observe all traffic laws and
briskly accelerate through the gears several times. The higher engine speed may help clean out valve seat deposits which can prevent accurate compres­
sion readings.

CAUTION:
DO NOT
overspeed
the
engine.
(d) Remove all spark plugs from engine. As
spark plugs are being removed, check electrodes for
abnormal firing indicators - fouled, hot, oily, etc.
Record cylinder number of spark plug for future
reference.
(e) Disconnect coil wire from distributor and se­
cure to good ground to prevent a spark from start­
ing a fire.
(f) Be sure throttle blades are fully open during
the compression check. (g) Insert compression gage adaptor into the
No.l spark plug hole. Crank engine until maxi­
mum pressure is reached on gauge. Record this
pressure as No.l cylinder pressure.
(h) Repeat Step 3g for all remaining cylinders.
(i) Compression should not be less than 689 kPa
(100 psi) and not vary more than 172 kPa (25 psi)
from cylinder to cylinder.
(j) If cylinder(s) have abnormally low compres­
sion pressures, repeat steps 3a through 3h. (k) If the same cylinder(s) repeat an abnormally
low reading, it could indicate the existence of a
problem in the cylinder.
The recommended compression pressures are
to be used only as a guide to diagnosing engine
problems. An engine should NOT be disassem­ bled to determine the cause of low compression
unless some malfunction is present. (4) Clean or replace spark plugs as necessary. Ad­
just gap (refer to Group 8D, Ignition System for gap adjustment and torque).
(5) Test resistance of spark plug cables (refer to
Group 8D, Ignition System.
(6) Inspect the primary wire. Test coil output volt­

age,
primary and secondary resistance. Replace parts as necessary (refer to Group 8D, Ignition System and
make necessary adjustment).
(7) Set ignition timing to specifications (refer to
Specification Label on engine compartment hood).
(8) Perform a combustion analysis.
(9) Test fuel pump for pressure and vacuum (refer
to Group 14, Fuel System for the proper specifica­

tions).

(10) Inspect air filter element (refer to Group 0,
Lubrication and Maintenance for the proper proce­
dure).

(11) Inspect crankcase ventilation system (refer to
Group 0, Lubrication and Maintenance for the proper
procedure).
(12) For emission controls refer to Group 25, Emis­
sion Controls System for service procedures.
(13) Inspect and adjust accessory belt drives (refer
to Group 7, Cooling System for the proper adjust­
ments).

(14) Road test vehicle as a final test.

H0NIN6
CYLINDER
BORES
Before honing, stuff plenty of clean shop towels un­
der the bores and over the crankshaft to keep abra­ sive materials from entering the crankshaft area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823 equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim­
its.

CAUTION:
DO NOT use rigid type
hones
to remove

cylinder
wall
glaze.

(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin­
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). 20-60 strokes, de­
pending on the bore condition, will be sufficient to
provide a satisfactory surface. Using honing oil C-3501-3880 or a light honing oil available from ma­
jor oil distributors.

CAUTION:
DO NOT use engine or
transmission
oil, mineral
spirits
or
kerosene.

•

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

9
- 12
ENGINES

•
CONDITION

POSSIBLE
CAUSES
CORRECTION

EXCESSIVE
EXHAUST

SMOKE
(Cont'd)
More
than
one
sealing washer
under an injector.
Check
and remove
extra
washer.
Improperly operating injectors.
Check
and replace inoperative injectors.
Improperly operating or over-
fueled injection pump.
Replace
injection pump.

Piston
rings
not sealing
(blue smoke). Perform blow-by check. Correct as required.

ENGINE
WILL
NOT

SHUT-OFF
Fuel shutoff valve inoperative.

Engine
running on fumes drawn into the air intake.
Stop
the engine mechanically
with
lever on the
fuel
pump.

Check/replace
sealing washer, piston and
spring.

Check
the air intake ducts for the source of the fumes.
WARNING:
In
ease
of engine runaway due to flammable
fumes

from gasoline spills or turbocharger oil leaks
being
sucked
into the
engine,
shut off engine ignition switch first then use a CO* or dry
chemical type
fire
extinguisher
and direct the
spray
under
the
front
bumper to
remove
oxygen
supply. The engine air
intake
is on the

passenger
side
behind the bumper. The
fire
extinguisher
must
bo
directed at this location for emergency shutdown conditions.

COOLANT
TEMPERA­

TURE
ABOVE
NORMAL
Low
coolant level.
(a) Check coolant level. Add coolant, if necessary.
(b) Locate and correct the source of the coolant leak. Refer to
troubleshooting
logic for coolant
loss.

Incorrect/improperly operating

pressure
cap.
Replace
cap
with
the correct rating for the
system.

High
lube oil level.
Check/drain
oil to correct level.

Loose
drive belt on water

pump/fan.
Check/replace
belt or belt tensioner.
Inadequate air flow to the radiator. Check/repair radiator core, fan shroud and fan clutch as
required.

Radiator
fins
plugged.
Blow
debris from fins.

Collapsed
radiator
hose.
Replace
the
hose.

Improperly operating tempera­

ture
sensor/gauge.
Verify
that
the
gauge
and temperature
sensor
are accurate.

Replace
gauge/sensor,
if bad.
Improperly operating, incorrect

or
no thermostat.
Check
and replace the thermostat.

Air
in the cooling
system.
(a) Make sure the
fill
rate
is not being exceeded and the correct
vented thermostat is installed.
(b) Check for loose hose
clamps.
Tighten if
loose.

(c) If aeration continued, check for a
compression
leak through the head gasket.
Inoperative water pump.
Check
and replace the water pump.
incorrect injection pump timing. Verify pump timing marks are aligned. Check/time the injector

pump
(refer
to Group 7,
Cooling
System).
J9209-56
SERVICE DIAGNOSIS (DIESEL ENGINE) - PERFORMANCE (CONT.)

•

ENGINES
9 - 13

CONDITION
POSSIBLE
CAUSES
COfiiiECTION

COOLANT
TEMPERA­

TURE
ABOVE
NORMAL
(Cont'd)
Overfueled injection pump.

Plugged
cooling
passages
in
radiator, head, head gasket or

block.

Engine
overloaded.
Replace
the injection
pump.

Flush
the
system
and
fill
with
clean coolant.
Verify
that
the engine load rating is not being exceeded.

COOLANT
TEMPERA­

TURE
BELOW
NORMAL
Too
much air flow
across
the
radiator.
Incorrect thermostat, broken
thermostat jiggle pin or

contamination
in thermostat.
Temperature
sensor
or
gauge
inoperative.

Coolant
not flowing by
temperature
sensor.
Check/repair
viscous
fan as required.

Check
and replace thermostat.
Verify
that
the
gauge
and
sensor
are accurate. If not, replace

gauge/sensor.

Check
and clean coolant
passages.

J9109-254
SERVICE DIAGNOSIS (DIESEL ENGINE) • PERFORMANCE (CONT.)

9
- 14
ENGINES
— — — •

SERVICE
DIAGNOSIS (DIESEL ENGINE)
•
MECHANICAL

CONDITION

r— ———
POSSIBLE
CAUSES
CORRECTION

LUBRICATING
OIL

PRESSURE
LOW Low oil
level.

(a)
Check
and
fill
with
clean engine oil.
(b) Check for a severe
external
oil leak
that
could reduce the pressure.
Oil viscosity thin,
diluted
or wrong specification.
Verify
the correct oil is being
used.
Check for oil dilution. Refer
to Contaminated Lube Oil (Engine Diagnosis—Mechanical).
Improperly operating pressure

switch/gauge.
Verify
the pressure switch is functioning correctly. If not,
replace switch/gauge.
Relief valve stuck open. Check/replace valve.

Plugged
oil
filter.
Change
oil
filter.
Oil
filter
change
interval
may need to be
revised.
If cooler was replaced, shipping

plugs
left
in cooler. Check/remove shipping
plugs.

If pump replaced, four cylinder
oil pump installed in a six
cylinder engine.
Verify
that
the correct pump is installed. If not, install an oil
pump for a six cylinder engine.

Loose
or
missing
cup
plugs.
Check and replace cup
plugs.

Worn oil pump. Check and replace oil pump.

Suction
tube
loose or seal leaking. Check and replace seal.

Loose
main bearing cap. Check and
install
new bearings and tighten cap to proper torque.
Worn bearings or wrong bearings installed. inspect and replace connecting rod or main bearings. Check and
replace piston cooling nozzles.

J9109-237