DODGE TRUCK 1993 Service Repair Manual

VACUUM
LINE
PROTECTIVE
CAP
INTERNAL
FUEL FILTER FUEL
PRESSURE
REGULATOR FUEL RAIL
CONNECTOR
HOSES
J9214-27

Fig.
22
Fuel
Pressure
Regulator—5.2L
Engine
pressure
and
intake manifold vacuum operate
on the

other side. Spring pressure
on one
side
of the
dia­
phragm tries
to
force
the
return valve closed. Fuel
pressure
on
other side
of
diaphragm, with assistance from manifold vacuum
on
spring side
of
diaphragm, act against spring pressure
to
open
the
return valve.
System fuel pressure
is the
amount
of
fuel pressure
required
to
force against spring pressure
and
unseat
the return valve.
Without vacuum applied
to the
spring side
of the

regulator,
the
spring
is
calibrated
to
open
the
fuel
re­

turn outlet. This happens when
the
pressure differen­
tial between
the
fuel injectors
and the
intake
manifold reaches approximately
269 kPa (39 psi).

Since manifold vacuum varies with engine operating
conditions,
the
amount
of
vacuum applied
to the

spring side
of the
diaphragm varies.
For
this reason,
fuel pressure varies, depending upon intake manifold
vacuum. With
low
vacuum, such
as
during wide open
throttle conditions, minimal vacuum assistance
is
available. Full spring pressure
is
exerted
to
seal
the

fuel outlet. This causes
the
system pressure
to in­

crease. With high vacuum, such
as at
engine idle
or

during vehicle deceleration, fuel pressure
on one
side
of
the
diaphragm
is
balanced
by
intake manifold
pressure. This
is
done
on the
spring side
of the
dia­
phragm
and
results
in
lower system fuel pressure.
5.9L
ENGINE
On vehicles equipped with
a 5.9L
engine,
the
fuel
filter and fuel pressure regulator
are one
combined
part
(Fig. 23). The
fuel filter/fuel pressure regulator is located
on the top of the
fuel pump module
(Fig.

24).
It is
pressed into
a
rubber grommet
on
module (Fig.
23).
Regulator Operation:
The
fuel pressure regulator
RUBBER
GROMMET AT PUMP MODULE FUEL FILTER/FUEL
PRESSURE REGULATOR
CALIBRATED SPRINGS
X
EXCESS FUEL BACK
TO TANK
FUEL INLET J9314-170

Fig.
23
Side
View—Filter/Regulator—5.9L
Engine

LOCKNUT FUEL SUPPLY
TUBE FUEL FILTER/
FUEL PRESSURE REGULATOR PUMP/GAUGE

ELEC.
CONNECTION
PRESSURE RELIEF/
, I I

ROLLOVER VALVE
J9314-167
Fig.
24
Filter/Regulator Location—5.9L
Engine

is
a
mechanical device that
is not
controlled
by the

powertrain control module (PCM).
The regulator
is
calibrated
to
maintain fuel system
operating pressure
at
approximately 241-310
kPa

(35-45
psi).
The regulator contains
a
diaphragm, calibrated
springs
and a
fuel return valve.
The
internal fuel fil­
ter
(Fig. 23) is
part
of the
assembly. Fuel
is
supplied
by the
electric fuel pump through
an opening tube
at the
bottom
of
filter/regulator
(Fig.
23).
The
calibrated pressure regulator allows
a
con­
stant fuel system operating pressure
of
approxi­
mately 241-310
kPa
(35-45
psi).
Fuel flows through
regulator
and
fuel filter
and on to
fuel injectors
at
engine. If
the
fuel pressure
at
regulator exceeds approxi­
mately
45 psi, an
internal diaphragm closes
and ex­
cess fuel pressure
is
routed back into pump module and returned
to
fuel tank
(Fig. 23).

MULTI-PORT
FUEL
INJECTION
(MPI)—GENERAL DIAGNOSIS—EXCEPT DIESEL

INDEX

page

Camshaft Position Sensor Testing
............
52
Charge
Air
Temperature Sensor Test
52

Coolant Temperature Sensor Test
52

Crankshaft Position Sensor Test
54

Diagnostic Trouble Code (DTC)
60

DRB
II
Scan
Tool
........................
60

Fuel
Injector
Test
57

Fuel Pump Pressure Test
57
Idle
Air
Control
(IAC) Motor Test
55

Manifold Absolute Pressure (MAP) Sensor Test
. 53
page

On-Board
Diagnostics (OBD)
59

Oxygen
(02)
Sensor Heating Element Test
54
Powertrain
Control
Module (PCM) 60-Way Connector
. 47

Relays—Operation/Testing
56

Starter
Motor Relay Test
57

System
Schematics
. 47

Throttle
Position Sensor (TPS) Test
54

Visual Inspection
43

VISUAL
INSPECTION
A visual inspection
for
loose, disconnected,
or
incor­
rectly routed wires
and
hoses should
be
made. This should
be
done before attempting
to
diagnose
or
ser­
vice
the
fuel injection system.
A
visual check will
help spot these faults
and
save unnecessary test
and
diagnostic time.
A
thorough visual inspection will
in­

clude
the
following checks: (1) Verify that
the
60-way connector
is
fully
in­

serted into
the
connector
of the
powertrain control
module
(PCM) (Fig. 1).
Verify that
the
connector
mounting screw
is
tightened
to 4 N#m (35 in. lbs.)
torque.
PCM
MOUNTING
BOLTS

PCM CONNECTOR CONNECTOR MOUNTING BOLT
J9314-165

Fig.
1
Powertrain Control
Module
(PCM) (2) Inspect
the
battery cable connections.
Be
sure
that they
are
clean
and
tight.
(3) Inspect fuel pump relay
and air
conditioning
compressor clutch relay
(if
equipped). Inspect
the

ASD relay connections. Inspect starter motor relay connections. Inspect relays
for
signs
of
physical dam­
age
and
corrosion.
The
relays
are
located
in the en­

gine compartment
(Fig. 2).
TORQUE CONVERTER
CLUTCH RELAY
A/C
CLUTCH RELAY STARTER RELAY
AUTO SHUTDOWN RELAY FUEL PUMP RELAY POWERTRAIN
DATA UNK CONTROL
CONNECTOR MODULE
J9314-164

Fig.
2
Relay Location (4) Inspect ignition coil connections. Verify that
coil secondary cable
is
firmly connected
to
coil (Fig.
3

or 4).
|X COIL

frCONNECTOR J9214-7

Fig.
3
Ignition Coil—3.9U5.2L/5.9L
LDC-Gas
Engine

14 - 44
FUEL
SYSTEM

•

Fig.
4 ignition Coil—5.9L
HDC-Gas
Engine
(5) Verify that distributor cap is correctly attached
to distributor. Be sure that spark plug cables are
firmly connected to the distributor cap and the spark
plugs are in their correct firing order. Be sure that coil cable is firmly connected to distributor cap and
coil. Be sure that camshaft position sensor wire con­
nector (at the distributor) is firmly connected to har­
ness connector. Inspect spark plug condition. Refer to Group 8D, Ignition. Connect vehicle to an oscillo­
scope and inspect spark events for fouled or damaged
spark plugs or cables.
(6) Verify that generator output wire, generator
connector and ground wire are firmly connected to
the generator. (7) Inspect the system body grounds for loose or
dirty connections. Refer to Group 8, Wiring for
ground locations. (8) Verify positive crankcase ventilation (PCV)
valve operation. Refer to Group 25, Emission Control System for additional information. Verify PCV valve
hose is firmly connected to PCV valve and manifold (Fig. 5).
Fig.
5 PCV
Valve
Hose
Connections—Typical (9) On 3.9L and 5.2L engines, verify that vacuum
hose is firmly connected to fuel pressure regulator and manifold fitting (Figs. 6 or 7).

CONNECTOR
HOSES
J9214-27

Fig.
7
Pressure
Regulator
Vacuum
Hose—5.2L
Engine

(10) Inspect fuel* tube quick-connect fitting-to-fuel
rail connections. (11) Verify that hose connections to all ports of
vacuum fittings on intake manifold are tight and not leaking.

•

FUEL
SYSTEM
14-45 (12) Inspect accelerator cable, transmission throt­
tle cable (if equipped) and cruise control cable con­
nections (if equipped). Check their connections to the
throttle arm of throttle body for any binding or re­ strictions (Fig. 8).

Fig.
8
Throttle
Body
Cables—Typical
(13) If equipped with vacuum brake booster, verify
that vacuum booster hose is firmly connected to fit­
ting on intake manifold. Also check connection to
brake vacuum booster.
(14) Inspect the air cleaner inlet and air filter ele­
ment for dirt or restrictions.
(15) Inspect radiator grille area, radiator fins and
air conditioning condenser for restrictions. (16) Verify that the intake manifold charge air
temperature sensor wire connector is firmly con­ nected to harness connector (Figs. 9 or 10).

Fig.
9 Air
Temperature
Sensor—3.9L
(V-6)
Engine
(17) Verify that MAP sensor electrical connector is
firmly connected to MAP sensor (Fig. 11). Also verify
that rubber L-shaped fitting from MAP sensor to the
throttle body is firmly connected (Fig. 12).
(18) Verify that fuel injector wire harness connec­
tors are firmly connected to injectors in the correct
Fig.
10 Air
Temperature
Sensor—5.2U5.9L
(V-8)

Engines
MANIFOLD
ABSOLUTE

Fig.
11 MAP Sensor—Typical
order. Each harness connector is numerically tagged
with the injector number (INJ 1, INJ 2 etc.) of its
corresponding fuel injector and cylinder number.
(19) Verify harness connectors are firmly con­
nected to idle air control (IAC) motor, throttle posi­
tion sensor (TPS) and manifold absolute pressure (MAP) sensor (Fig. 11).
(20) Verify that wire harness connector is firmly
connected to the engine coolant temperature sensor (Fig. 13).
(21) Raise and support the vehicle.
(22) Verify that oxygen sensor wire connector (or
connectors) are firmly connected to the sensor (or sensors). Inspect sensor(s) and connector(s) for dam­age (Figs. 14 or 15).

14
- 46
FUEL
SYSTEM

Fig.
12
Rubber
L-Shaped
Fitting—MAP
Sensor-to-
Throttie
Body

Fig.
13
Engine
Coolant
Temperature
Sensor—
Typical
EXHAUST
~~

PIPE
J9214-5

Fig.
14
Single
Oxygen
Sensor
Location-3.9U5.2L/ 5.9L LDC
Engine

(23) Inspect for pinched or leaking fuel tubes. In­
spect for pinched, cracked or leaking fuel hoses. •

Fig.
15
Dual
Oxygen
Sensor
Location—5.9L HDC
Engine
(24) Inspect for exhaust system restrictions such as
pinched exhaust pipes, collapsed muffler or plugged catalytic convertor.
(25) If equipped with automatic transmission, ver­
ify that electrical harness is firmly connected to
park/neutral switch. Refer to Automatic Transmis­ sion section of Group 21.
(26) Verify that the harness connector is firmly
connected to the vehicle speed sensor (Fig. 16).

Fig.
16 Vehicle
Speed
Sensor—
Typical

(27) Verify that fuel pump/gauge sender unit wire
connector is firmly connected to harness connector.
(28) Inspect fuel hoses at fuel pump/gauge sender
unit for cracks or leaks.
(29) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel. (30) Verify that battery cable and solenoid feed
wire connections to the starter solenoid are tight and clean. Inspect for chaffed wires or wires rubbing up against other components.

•
FUEL SYSTEM 14-47 POWERTRAIN CONTROL MODULE (PCM)
60-WAY

CONNECTOR
Terminal identification and specific circuit applica­
tions are shown in the PCM connector chart (Fig.
17).
Also refer to Group 8W, Wiring Diagrams.
SYSTEM
SCHEMATICS

Fuel system schematics for fuel injected engines
are shown in figures 18, 19 and 20.

CAV

WIRE

COLOR DESCRIPTION
CAV
WIRE

COLOR DESCRIPTION

1 DG/RD*
MAP SENSOR 37
BK/OR OVERDRIVE LAMP
2 TN/BK*
ENGINE COOLANT TEMPERATURE SENSOR 38 PK/BK INJECTOR DRIVE
#5

3 RD/WT DIRECT BATTERY 39 GY/RD IAC MOTOR
#4

4
BK/LB*

SENSOR RETURN 40 BR/WT
IAC MOTOR
#2

5 BK/WT SIGNAL GROUND 41
BK/DG* OXYGEN SENSOR SIGNAL
6 VT/WT
5-VOLT
OUTPUT
(MAP AND TPS)
42
7 OR

8-VOLT
OUTPUT (DISTRIBUTOR PICK-UP) 43

GY/LB*
TACHOMETER SIGNAL OUTPUT (VEHICLES W/TACHOMETER)
8 44 GY CAMSHAFT POSITION SENSE
9 DB
J2-IGNITION FEED 45
LG SCI RECIEVE
10 R/WT OVERDRIVE OVERRIDE
46 CCD
(-)

11 BK/TN POWER GROUND 47 WT/OR* SPEED SENSOR SIGNAL
12 BK/TN POWER GROUND 48 BR/RD* SPEED CONTROL
SET
SWITCH
13 LB/BR
INJECTOR DRIVER
#4
49
YL/RD* SPEED CONTROL ON/OFF SWITCH
14 YL/WT
INJECTOR DRIVER
#3
50 WT/LG* SPEED CONTROL RESUME SWITCH
15 TN INJECTOR DRIVER
#2
51 DB/YL*
AUTO SHUTDOWN
(ASD)
RELAY
-
RETURN
16
WT/DB*

INJECTOR DRIVER
#1
52 PK/BK
EVAP CANISTER PURGE SOLENOID
17 DB/TN INJECTOR DRIVER
#7
(V-8
ONLY) 53 LG/RD* SPEED CONTROL VENT SOLENOID
18 DB/GY
INJECTOR DRIVER
#8
(V-8
ONLY) 54
OR/BK* SHIFT INDICATOR LIGHT (MANUAL TRANSMISSION ONLY)
19 BK/GY*
IGNITION COIL DRIVER 54
OR/BK* CONVERTOR CLUTCH SOLENOID (AUTO TRANSMISSION)
20 DG
GENERATOR FIELD CONTROL 55
OR/WT OVERDRIVE SOLENOID (AUTO TRANSMISSION ONLY)
21 BK/RD
CHARGE TEMPERATURE SENSOR 56
GY/PK SRI LAMP
(5.9L HDC
ENGINE)
22
OR/DB*

THROTTLE POSITION SENSOR
(TPS)
57
DG/OR ASD SENSE
23 TN/WT
OXYGEN SENSOR SIGNAL
(5.9L HDC
ENGINE) 58 LG/BK
INJECTOR DRIVER
#6

24 GY/BK IGNITION (CAMSHAFT POSITION SENSOR) 59
VT/BK IAC MOTOR
#1

25 PK
,
SCI
TRANSMIT 60
YL/BK* IAC MOTOR
#3

26 CCD
(-:-)
WIRE COLOR CODES LB
LIGHT BLUE
VT VIOLET

27 BR
A/C SWITCH SENSE BK BLACK
LG LIGHT GREEN
WT

WHITE
28 VT A/C SELECT BR BROWN
OR ORANGE
YL YELLOW
29 WT/PK* BRAKE SWITCH
-
DB DARK BLUE PK
PINK *
WITH TRACER
30 BY/YL*
PARK/NEUTRAL SWITCH DG DARK GREEN
RD
RED
31 GY
GRAY TN TAN
32 BK/PK*
MALFUNCTION INDICATOR LAMP
33 TN/RD*
SPEED CONTROL VACUUM SOLENOID CONNECTOR
34 DB/OR* A/C CLUTCH RELAY TERMINAL

|(pcKX>coooop0ffoj'
oooooooooojj
35 GY/YL*
EGR SOLENOID SHOWN W'41
30
50«M#5l31
604

%\
oooooooooo ••ooooooooooj

36 J9314-171
Fig.
17 PCM
Connector—Gas
Powered
Engines

•

THROTTLE

POSITION
SENSOR
CO

Fig. 18 System Schematic—3.9L (V-6) Engine
CO

CJ1
m
r-

co
-<

CO

J9314-120

Fig. IS System Schematic—5.2U5.9L LDC (V-8) Engine

-<

m

J9314-172

Fig.
20 System
Schematic-SSL
HDC (V-8) Engine