fuel pressure DODGE TRUCK 1993 Service Owner's Guide

WIRING
DIAGRAMS
8W - 101

G20
20VT/YL

ENGINE COOLANT
TEMPERATURE GAUGE SENDING
UNIT
(SEE
SH 27,28)

L61
18LG
LEFT TURN SIGNAL LAMP
(SEE
SH 56)

G7
20WT/0R
VEHICLE SPEED SENSOR
(SEE
SH 19,25)
GRAY

G13 20DB/RD SEAT BELT WARNING LAMP SWITCH
(SEE
SH 77,78)

G3 20BK/PK MALFUNCTION INDICATOR LAMP)
(SEE
SH 58)

G5
20DB/WT
IGNITION FEED-12 VOLTS
(SEE
SH 58)

LEFT CONNECTOR

BLACK
E2
200R
ILLUMINATION LAMP FEED

(SEE
SH 48)

Zl 20BK GROUND
(SEE
SH 48)

G4
20DB
FUEL GAUGE SENDING
UNIT
(SEE
SH 77,78)
G6
20GY
ENGINE
OIL
PRESSURE LAMP SWITCH

(SEE
SH 27,28)

G5
20DB/WT
IGNITION FEED-12 VOLTS
(SEE
SH 58,77,78)

G34 16RD/GY HIGH-BEAM INDICATOR LAMP
(SEE
SH 43,45)

L60
18TN
RIGHT TURN SIGNAL LAMP
(SEE
SH 56)
G60 20GY/YL ENGINE
OIL
PRESSURE GUAGE

SENDING
UNIT
(SEE
SH 27,28)

RIGHT CONNECTOR
J938w-ii
PRINTED CIRCUIT BOARD CONNECTORS

AD
60

8W - 126
WIRING
DIAGRAMS
SMALL
INDEX
50 49 48
47
46 45
44 43 42 41
40 39
38 37
36 35
34 33 32
© 31
30 29
28 27
26
© 25
24 23
22 21
20 ©
19 18
17
16 15 14 13 12 11 10 9 8 7
6 5 4
3 2
1
LARGE

INDEX TERMINAL END
OF DISCONNECT
ENGINE COMPARTMENT CAVITY

1

10
11
12
13
14 15
16
17
18 19
20
21
22
23
24
25
26
27
28
29
30 31
32 33
34
35
36
37
38
39 40
41
42
43
44
45
46
47
48
50 ENGINE COMPARTMENT CIRCUITS
A3 12RD/WT C7 12BK/TN
A141 16DG/BK
L4
16VT/WT

L3 14RD/0R
V30 20DB/RD
V31 20BR/RD V33
20WT/LG

V32 20YL/RD

E5
20DG/WT

G34 16RD/GY
L20
14LG/WT

G21 20GY/LB G20
20VT/YL

G6 20GY
G60 20GY/YL
G85 20TN/OR
L61 18LG L60 18TN
A15 16PK
T61 20BK/0R
LI 18VT/BK
L7 18BK/YL
F20 18WT
V10 20BR
A41 16YL
X2 18DG/RD
Ml 18BK/TN
Gil
20WT/BK

V5 18DG/YL
V6 18DB
C21 18DB/0R
G3 20BK/PK
X4 20LG/BR V40 18WT/PK
G24 20GY/PK
G7 2GWT/0R T6
200R/WT

V3 18BR/WT
V4 18RD/YL
A21 14DB
A4 12BK/RD Al 12RD
A2 12PK/BK HEADLAMP SWITCH

A/C
AND HEATER BLOWER MOTOR
FUEL PUMP FEED (GAS ONLY)
HEADLAMP LOW BEAM (2 WIRES)
HEADLAMP HIGH BEAM (2 WIRES)
VEHICLE
SPEED
CONTROL
VEHICLE
SPEED
CONTROL VEHICLE
SPEED
CONTROL
VEHICLE
SPEED
CONTROL

WAIT
TO START LAMP (DIESEL
QNLYr

HIGH BEAM INDICATOR LAMP
HIGH BEAM FEED
TACHOMETER SIGNAL (DIESEL)
ENGINE COOLANT TEMPERATURE SENDING
UNIT

ENGINE OIL
PRESSURE
SWITCH
ENGINE OIL
PRESSURE
SENDING
UNIT

WATER-IN FUEL LAMP (DIESEL)
LEFT TURN SIGNAL LAMP RIGHT TURN SIGNAL LAMP
BATTERY-HAZARD FLASHER
TRANSMISSION
OVERDRIVE INDICATOR LAMP
BACK-UP LAMPS
PARKING LAMPS (2 WIRES)
BACK-UP LAMP SWITCH
WINDSHIELD WASHER MOTOR
ENGINE STARTER RELAY
-1GNITI
ON HORN
UNDERHOOD LAMP

ELECTRIC
VACUUM
SENSOR
(DIESEL) (2 WIRES)
WINDSHIELD WIPER MOTOR
WINDSHIELD WIPER MOTOR
AIR CONDITIONING DAMPED
PRESSURE
SWITCH
MALFUNCTION INDICATOR LAMP
4 WHEEL DRIVE SWITCH

BRAKE
SENSOR
SRI
LAMP (GAS ENGINE ONLY)
VEHICLE
SPEED SENSOR

TRANSMISSION
OVERDRIVE
WINDSHIELD WIPER MOTOR
WINDSHIELD WIPER MOTOR
SPLICE-IGNITION RUN CIRCUIT
IGNITION
OFF DRAW

IGNITION
SWITCH
IGNITION
SWITCH
AD 85 50-WAY BULKHEAD DISCONNECT
J938W-11

•

WIRING
DIAGRAMS
8W - 127
CAVITY
INSTRUMENT PANEL CIRCUITS

1

10
11
12

13
14

15

16
17
18
19
20
21
22

23

24
25

26
27
28 29
30 31
31
32

33

34

35

36
37
38
39
40
41
42

43

44

45
46
47
48
49
50
A3
12RD/WT

C7 12BK/TN
A61 16DG/BK
L4
16VT/WT

L3
16RD/0R

V30 20DB/RD
V31 20BR/RD
V33
20WT/LG

V32 20YL/RD
V32 20YL/RD G86
20DG/WT

G34 16RD/GY
L20
20LG/WT

G21 20GY/LB
G20
18VT/YL

G6
20GY

G60 20GY/YL G85
20TN/0R

L61
18LG

L61
18LG

L60
18TN

L60
18TN
A15
16PK

T61 20BK/OR
LI
18VT/BK

L7 18BK/YL
F20
18WT

V10 20BR
A41
14YL

S21 14YL/BK
X2
18DG/R0

Ml
18PK

Gil
20WT/BK
V5
18DG

V6
18DB
C2 18DB/YL
G3 20BK/PK
Gl 20DG/GY
V40
18WT/PK
G24 22GY/PK
G7
20WT/0R
T6
200R/WT

V3 18BR/WT
V4 18RD/YL
A21
14DB

A21
14DB

A4 12BK/RD
Al
12RD

A2 12PK/BK BATTERY FEED

A/C
AND
HEATER BLOWER MOTOR
FUEL PUMP FEED
(GAS
ONLY)
HEADLAMP-LOW BEAM
HEADLAMP-HIGH BEAM VEHICLE
SPEED
CONTROL
VEHICLE
SPEED
CONTROL VEHICLE
SPEED
CONTROL
VEHICLE
SPEED
CONTROL

WAIT
TO
START LAMP (DIESEL ONLY)
HIGH BEAM INDICATOR LAMP
HIGH BEAM FEED (D.R.L. MODULE)
TACHOMETER (DIESEL)
ECT SEND/UNIT
OR
SWITCH
ENGINE
OIL
PRESSURE
LAMP
ENGINE
OIL
PRESSURE
GAUGE-SEND
UNIT

WATER
IN
FUEL LAMP (DIESEL)
LEFT FRONT TURN SIGNAL LAMP
RIGHT FRONT TURN SIGNAL LAMP
HAZARD FLASHER
TRANSMISSION
OVERDRIVE INDICATOR LAMP

BACK-UP
LAMPS

PARKING
LAMPS

BACK-UP
LAMP FEED
WINDSHIELD WASHER MOTOR
IGNITION START
IGNITION START (DIESEL)

HORNS

UNDERHOOD LAMP
ELECTRIC VACUUM
SENSOR
(DIESEL) WINDSHIELD WIPER SWITCH
WINDSHIELD WIPER SWITCH
A/C
COMPRESSOR CLUTCH
MALFUNCTION INDICATOR
4 WHEEL DRIVE SWITCH

BRAKE
SENSOR

SRI
LAMP
(GAS
ENGINE ONLY)
VEHICLE
SPEED
SENSOR
(2
WIRES)
TRANSMISSION
OVERDRIVE SWITCH
WINDSHIELD WIPER
LOW
SPEED

WINDSHIELD WIPER HIGH
SPEED

IGNITION-RUN
I
START
BATTERY FEED IGNITION SWITCH
(Bl)

IGNITION SWITCH
(B3)
SHEET
NO

4,6.30,47
66,67,68 78
43,45,47
36,38
23

43,46
46,47
22
27,28
23

43.45,56
43,45.56

3,5,56
12,14 7.79
43,45,47
7.9
53.55 8,9
30
29
34
54,55 67,69 19,22

13

32,34,36,38
19

19,25
12,14
54.55
10,23.77,78
3.5.39

4,6.10
4.6.10
TERMINAL
END

OF DISCONNECT
ff
p
45 46
47
48 49
50
35 36 37
38 39
40 41
42
43 44
29 30 31
© 32
33 34
23 24
25
© 26
27 28
17 18
19 ©
20 21 22
7 8 9
10 11
12 13
14 15 16
1
^
1.
2
3
4 5 &

J *j

LARGE
INDEX
INSTRUMENT PANEL
J938W-11

50-WAY BULKHEAD
DISCONNECT
AD
86

8W - 130
WIRING
DIAGRAMS

•

1 2 3

A 4

5 6

7
8

/

9
10

11
/


12 13
14

15 16

/

17
18
19
20

21

u
22
23
24

25 26

u

27
28 29

30
31
u

32 33
34

u

35 36

37

38 39
u

40
41 42

u

VIEW FROM WIRE
END
HEADLAMP
I
DASH
WIRING
CAV
IGNITION
SYSTEM CIRCUITS
SHEET
NO

1 A21
14DB
IGNITION
FEED 16
2
Zl 14BK

GROUND
9.68

3

4
LI 18VT/BK BACK-UP LAMPS 9
5 K54 200R/BK
EMCC
SOLENOID
11
6 A141 16DG/BK
FUEL PUMP 16

7
C20
18BR
A/C
COMPRESSOR CLUTCH 18
8 G3 20BK/PK MALFUNCTION INDICATOR LAMP 19
9 A14
16RD
BATTERY FEED 16

10

11
Zll
16BK/WT

SIGNAL GROUND
17

12 V40 18WT/PK
BRAKE
SIGNAL 35
13 Z12 16BK/TN

POWER
GROUND
17
14
T41 18BR/YL ENGINE STARTER RELAY COIL 9
15 G60 20GY/YL ENGINE
OIL
PRESSURE
SEND/UNIT 28
16 G6 20GY
ENGINE
OIL
PRESSURE
SWITCH 28

17 T6
200R/WT
TRANSMISSION
OD
OVERRIDE 12
18 T61 20BK/0R

TRANSMISSION
OD
LAMP SIGNAL
12
19

20
F20
18WT

BACK-UP LAMP SWITCH 9
21
22 T22 14DB/WT
EMCC

11
23

24
G24 20GY/PK
SRI
LAMP
19
25 C13 20DB/0R
A/C
COMPRESSOR CLUTCH RELAY
18
26 G20
20VT/YL
ECT SEND/UNIT
28

27
V31 20BR/RD VEHICLE
SPEED
CONTROL-
SET
35
28 V32 20YL/RD VEHICLE
SPEED
CONTROL- OFF/ON
35
29 V33
20WT/LG
VEHICLE
SPEED
CONTROL- RESUME 35

30
V35 20LG/RD VEHICLE
SPEED
CONTROL- VENT
35
31 V36 20TN/RD VEHICLE
SPEED
CONTROL- VACUUM
35
32
33 G7
20WT/0R
VEHICLE
SPEED
SENSOR 19

34
C3 14DB/BK
A/C
COMPRESSOR CLUTCH FEED 68
35
36

37

38
39

40

41
42
&

GjCUQjQ

UXJUXj
O

"IT
mJKXTV
ENGINE WIRING

- ENG

AD
89
GAS
ENGINE WIRING CONNECTOR
J938W-11

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.

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 - 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

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.)