1993 DODGE TRUCK Service Repair Manual

14-6 FUEL
SYSTEM

•

I
l /////

PROTECTIVE
CAP AND
TEST
PORT

J9314-168

Fig.
8
Fuel
Pressure
Test Port—5.9L (V-8)
Engine
5.2L engine are equipped with a vacuum assisted
fuel pressure regulator (Figs. 6 or 7). With engine at
idle speed, system fuel pressure should be approxi­
mately 214 kPa (31 psi) with the vacuum line con­
nected to the regulator. With the vacuum line
disconnected from the regulator, fuel pressure should
be approximately 269 kPa (39 psi). This is 55-69 kPa (8-10 psi) higher.
(1) Remove the protective cap at the fuel rail (Figs.
6 or 7). Connect the 0-414 kPa (0-60 psi) fuel pres­
sure gauge (from Gauge Set 5069) to test port pres­
sure fitting on fuel rail (Fig. 9).

FUEL
PRESSURE
TEST GAUGE

J9214-28

Fig.
9
Fuel
Pressure
Test—
Typical

(2) Note pressure gauge reading. Fuel pressure
should be approximately 214 kPa (31 psi) at idle. (3) Disconnect vacuum line at fuel pressure regu­
lator (Figs. 6 or 7). Note gauge reading. With vac­ uum line disconnected, fuel pressure should rise to
approximately 269 kPa (39 psi).
Fuel pressure should be approximately 55-69 kPa
(8-10 psi) higher with vacuum line removed from
regulator. If not, inspect pressure regulator vacuum line for leaks, kinks or blockage. If vacuum line
checks OK and fuel pressure does not rise approxi­
mately 8-10 psi after disconnecting vacuum line, re­
place fuel pressure regulator.
The fuel pressure regulator is not adjustable. (4) If fuel pressure exceeds 45 psi, check fuel re­
turn line for kinks or obstructions. If the previous tests checked good, fuel pump pres­
sure is correct. If pump pressure was low, proceed as
follows:
(5) Release fuel system pressure. Refer to the pre­
vious Fuel Pressure Release Procedure in this group. (6) Disconnect the 5/16 inch fuel return line quick-
connect fitting (Fig. 10) on fuel rail near fuel pres­
sure regulator. Connect Fuel Line (Tube) Pressure
Test Adapter Tool number 6539 (5/16 in.) between
the disconnected fuel return tube and fuel rail (Fig.
11).
FUEL TUBE REMOVAL
QUICK CONNECT

FITTING

PUSH
INSTALLATION
X
PUSH-

/
PUSH
PLASTIC
RETAINER
J9314-100

Fig.
10
Removing
Quick-Connect
Fitting

WARNING:
THE
FUEL SYSTEM
PRESSURE
IN THE
FOLLOWING TEST
MAY
EXCEED
100
PSI.
BEFORE
STARTING TEST, VERIFY GOOD CONNECTIONS
AT

ENDS
OF
ADAPTER TOOL
6539.
BE
SURE TOOL
IS

LOCKED
ONTO FUEL RAIL
AND
FUEL RETURN

LINE.
PULL FIRMLY
ON
ENDS
OF
TOOL
TO
VER­
IFY.

(7) To activate the fuel pump and pressurize the
system, obtain the DRB II scan tool. Refer to the ap-

•

FUEL
SYSTEM
14 - 7

Fig.
1"f
Adapter Tool—Typical
Connection
propriate Powertrain Diagnostic Procedures service
manual for DRB II operation.
(8) MOMENTARILY pinch the rubber hose por­
tion of adapter tool 6539. Pressure should rise to ap­
proximately 75 psi within two (2) seconds. DO NOT
pinch hose for longer than five seconds.
If fuel pump pressure rises to approximately 75 psi
within two seconds, pump is operating at its maxi­ mum and is correct. If fuel pump pressure does not rise to approxi­
mately 75 psi within two seconds, proceed as follows:
(9) Release fuel system pressure. Refer to the pre­
vious Fuel Pressure Release Procedure in this group. (10) Raise and support vehicle.
(11) Disconnect fuel supply line at inlet (fuel tank
side) of fuel filter. Connect Fuel Line (Tube) Pressure
Test Adapter Tool number 6631 (3/8 in.) between fuel
filter and fuel supply line.

WARNING:
THE
FUEL SYSTEM
PRESSURE
IN THE
FOLLOWING TEST MAY EXCEED
100
PSI. BEFORE
STARTING TEST, VERIFY GOOD CONNECTIONS
AT
ENDS
OF
ADAPTER TOOL 6631.
BE
SURE TOOL
IS

LOCKED
ONTO FUEL FILTER
AND
FUEL SUPPLY

LINE.
PULL FIRMLY
ON
ENDS
OF
TOOL
TO
VER­
IFY.

(12) To activate the fuel pump and pressurize the
system, obtain the DRB II scan tool. Refer to the ap­
propriate Powertrain Diagnostic Procedures service manual for DRB II operation.
MOMENTARILY pinch the rubber hose portion of
adapter tool 6631. Pressure should rise to approxi­
mately 75 psi within two (2) seconds. DO NOT pinch
hose for longer than five seconds.
If fuel pump pressure now rises to approximately
75 psi within two seconds, but this pressure could not
be met at the fuel rail, check for a plugged or re­ stricted fuel filter. Also check the fuel supply line be­ tween fuel filter and fuel rail for kinks or
obstructions. Proceed to the Fuel Pump Capacity
Test.

FUEL
SYSTEM PRESSURE
TEST—5.9L
ENGINE
Fuel systems on vehicles equipped with a 5.9L en­
gine are equipped with a fuel tank module mounted,
combination fuel filter/fuel pressure regulator (Fig.
12).
The fuel pressure regulator is not controlled by
engine vacuum.

ROLLOVER VALVE J9314-167 Fig.
12
Fuel
Filter/Fuel
Pressure
Regulator—5.9L
Engine

With engine at idle speed, system fuel pressure
should be approximately 241-310 kPa (35-45 psi). (1) Remove the protective cap at the fuel rail (Fig.

13).
Connect the 0-414 kPa (0-60 psi) fuel pressure
gauge (from Gauge Set 5069) to test port pressure fit­
ting on fuel rail (Fig. 14).

Fig.
13
Fuel
Pressure
Test Port—5.9L
Engines

(2) Note pressure gauge reading. Fuel pressure
should be approximately 241-310 kPa (35-45 psi) at

idle.

Fig.
14
Fuel
Pressure
Test—Typical
(3) If pressure is at O psi, connect DRB II scan tool
and refer to operating instructions in the appropriate
Powertrain Diagnostics Procedures service manual. If operating pressure is above 45 psi, fuel pump is
OK. Replace fuel filter/fuel pressure regulator assem-
bly.

FUEL
PUMP CAPACITY TEST-ALL GAS ENGINES
Before performing this test, verify fuel pump pres­
sure by performing the previous tests. (1) Release the fuel system pressure from fuel sys­
tem. Refer to the previous Fuel Pressure Release
Procedure in this group. (2) Disconnect the fuel supply line at fuel rail near
pressure regulator. (3) Connect Fuel Line (Tube) Pressure Test
Adapter Tool number 6631 (3/8 in.) into the discon­ nected fuel supply line (tube). Insert the other end of
Adapter Tool 6631 into an approved gasoline con­
tainer.
(4)
To activate the fuel pump and pressurize the
system, obtain the DRB II scan tool. Refer to the ap­
propriate Powertrain Diagnostic Procedures service manual for DRB II operation. (5) 3.9L/5.2L Engines: A good fuel pump will de­
liver approximately 1 liter of fuel per minute. 5.9L
Engines: A good fuel pump will deliver approxi­
mately 2 liters of fuel per minute.

FUEL
PRESSURE
LEAK DOWN
TEST-3
JL/5.2L

ENGINE

ENGINE
OFF Abnormally long periods of cranking to restart a
hot engine that has been shut down for a short pe­ riod of time may be caused by:
• Fuel pressure bleeding past the fuel pressure reg­
ulator.
• Fuel pressure bleeding past the check valve in the
outlet end of the fuel tank mounted fuel pump. (1) Remove protective cap at fuel rail test port

(Figs.
15 or 16). With the engine off, connect an ac­
curate 0-689 kPa (0-100 psi) fuel gauge to the pres­
sure test port fitting on the fuel rail. The fitting on
the pressure tester must be in good condition and
free of any leaks before performing this test.
PRESSURE
REGULATOR

CONNECTOR
HOSES
J9214-27

Fig.
16
Fuel
Pressure
Test Port—5.2L
Engine

•

FUEL
SYSTEM
14 - 9 (2) Start the vehicle and let engine idle. Check
fuel pressure reading on gauge. Fuel pressure should
be within specifications. Refer to the previous Fuel System Pressure Tests.
(3) Shut engine off. Observe and record fuel pres­
sure reading on gauge. Leave fuel pressure gauge
connected. Allow engine to set for 30 minutes and
then compare the fuel pressure reading on the gauge
with the reading taken when engine was shut down.
A pressure drop of up to 138 kPa (20 psi) within 30 minutes is within specifications.
(4) If the fuel pressure drop is within specifica­

tions,
the fuel pump outlet check valve and fuel pres­ sure regulator are both operating normally.

(5)
If fuel pressure drop is greater than 138 kPa
(20 psi), it must be determined if this drop is being
caused by (in-tank mounted) fuel pump outlet check
valve or fuel pressure regulator. Proceed to next step. (6) Release the fuel system pressure from fuel sys­
tem. Refer to the previous Fuel Pressure Release
Procedure in this group. (7) Disconnect both fuel tubes (lines) at fuel rail
near fuel pressure regulator. (8) Connect Fuel Line (Tube) Pressure Test
Adapter Tool number 6631 (3/8 in.) between the dis­ connected fuel supply line and fuel rail (Fig. 17). (9) Connect Fuel Line (Tube) Pressure Test
Adapter Tool number 6539 (5/16 in.) between the dis­
connected fuel return line and fuel rail (Fig. 17).
Fig. 17 Adapter Tools—Typical Connections
(10) Start engine. Observe and record fuel system
pressure.
(11) Shut engine off.
(12) Clamp off the rubber hose portion of adapter
tool number 6539 connected to the fuel return line.
Allow engine to set for 30 minutes. If pressure has
dropped more than 138 kPa (20 psi) in 30 minutes,
pressure is bleeding past the (in-tank mounted) fuel pump outlet check valve. Replace Fuel Pump Module assembly. Refer to Fuel Pump Module removal and installation in this group. If pressure drop is within
specifications, proceed to next step.
(13) Clamp off the rubber hose portion of adapter
tool number 6631 connected to the fuel supply line.
Allow engine to set for 30 minutes. If pressure has
dropped more than 138 kPa (20 psi) in 30 minutes,
pressure is bleeding past the fuel pressure regulator.
Replace fuel pressure regulator. Refer to Fuel Pres­ sure Regulator removal and installation in the Com­
ponent Removal/Installation section of this group.

FUEL
PRESSURE
LEAK DOWN TEST—5.9L

ENGINE

ENGINE OFF Abnormally long periods of cranking to restart a
hot engine that has been shut down for a short pe­
riod of time may be caused by:
• Fuel pressure bleeding past a fuel injector.
• Fuel pressure bleeding past the check valve in the
fuel filter/fuel pressure regulator.
(1) Disconnect the fuel inlet tube at fuel rail (Fig.

18).
This is done by pushing on plastic part of quick-
connect fitting on tube (Fig. 19).
Fig. 18 Fuel Pressure Test Port—5.9L Engines
(2) Connect Fuel Line (Tube) Pressure Test
Adapter Tool number 6539 (5/16 in.) between the dis­
connected fuel tube and fuel rail.
(3) Connect the 0-414 kPa (0-60 psi) fuel pressure
test gauge (from Gauge Set 5069) to the test port on
tool 6631. The fittings on both tools must be in good condition and free from any small leaks
before performing the proceeding test,
(4) Start engine and bring to normal operating
temperature.
(5) Observe test gauge. Normal operating pressure
should be 241-310 kPa (35-45 psi). (6) Shut engine off.
(7) Pressure should not fall below 24 psi for five
minutes.

FUEL
TUBE

REMOVAL

QUICK
CONNECT

FITTING

PUSH
PUSH PUSH

INSTALLATION

X
PUSH

/

•PUSH

PLASTIC

RETAINER
J9314-100

Fig. 19 Removing/Installing Quick-Connect Fitting (8) If pressure falls below 24 psi, it must deter­
mined if a fuel injector, the fuel module mounted fuel
pressure regulator or a fuel tube/line is leaking. (9) Again, start engine and bring to normal oper­
ating temperature.
(10) Shut engine off.
(11) Checking for fuel injector leakage: Clamp
off the rubber hose portion of tool 6539 between the
disconnected fuel tube (line) and test port inlet. If
pressure now holds at or above 24 psi, a fuel injector or the fuel rail is leaking.
Checking for fuel pressure regulator or fuel
tube leakage: Clamp off the rubber hose portion of
tool 6539 between the fuel rail and test port inlet. If
pressure now holds at or above 24 psi, a leak can be
found at a fuel tube/line. If no leaks are found at fuel

tubes,
replace the fuel filter/fuel pressure regulator.

MECHANICAL MALFUNCTIONS
Mechanical malfunctions are more difficult to diag­
nose with this system. The powertrain control mod­
ule (PCM) has been programmed to compensate for
some mechanical malfunctions such as incorrect cam
timing, vacuum leaks, etc. If engine performance
problems are encountered and a diagnostic trouble code (DTC) is not displayed, the problem may be me­
chanical rather than electronic.

FUEL FILTER-3.9L/5.2L GAS ENGINE
For diesel engines, refer to Fuel/Water Separator
Filter in the Diesel Fuel Injection—Service Proce­
dures section of this group.
REMOVAL

WARNING:
THE
FUEL
SYSTEM
IS
UNDER
A
CON­
STANT
PRESSURE
(EVEN
WITH
THE
ENGINE
OFF).
BEFORE
SERVICING
THE
FUEL FILTER,
THE
FUEL
SYSTEM
PRESSURE
MUST
BE
RELEASED.

The fuel filter is located under the vehicle and near
the fuel tank. It is mounted to the frame rail (Fig.
20). (1) Perform Fuel System Pressure Release proce­

dure.
(2) Disconnect negative battery cable from battery.
(3) Raise and support vehicle.
(4) Remove and discard both fuel hose-to-fuel filter
hose clamps. (5) Wrap a shop towel around hoses to absorb fuel.
Remove hoses at filter. (6) Remove filter from frame.
FUEL
HOSES
HOSE
CLAMPS
.
FILTER
MOUNTING
BOLT
FUEL

FILTER

J9214-68

Fig.
20
Fuel
Filter—3.9U5.2L
Engine

INSTALLATION

CAUTION:
The
tubes/hoses used
on
fuel
injected

vehicles
are of a
special construction. This
is due

to
the
higher
fuel
pressures
and the
possibility
of
contaminated
fuel
in
this system.
If it is
necessary
to replace these tubes/hoses, only tubes/hoses marked EFM/EFI
may be
used.

CAUTION:
The
hose clamps used
on
fuel
injected

vehicles
are of a
special rolled edge construction
to
prevent
the
edge
of the
clamp from cutting into
the
hose.
Only these rolled edge
type
clamps
may be

used
in
this system.
All
other types
of
clamps
may

cut into
the
hoses
and
cause high pressure
fuel
leaks.

(1) Install fuel filter to frame rail. Tighten mount­
ing bolt to 8 N»m (75 in. lbs.) torque. (2) Install new original equipment clamps to fuel

hoses.

•

FUEL SYSTEM
14-11 (3)
Install hoses
to
filter. Tighten clamps
to 1 N*m
(10 in. lbs.)
torque. (4) Lower vehicle.

(5)
Connect battery cable
to
battery.
(6) Start engine
and
check
for
leaks.

FUEL
FILTER—5.9L
GAS ENGINE
For diesel engines, refer
to
Fuel/Water Separator
Filter
in the
Diesel Fuel Injection—Service Proce­
dures section
of
this group. The fuel filter
and
fuel pressure regulator
(Fig. 21)

are
one
non-repairable component.
For
service, refer
to Fuel Filter/Fuel Pressure Regulator. This
can be

found
in the
Multi-Port Fuel Injection (MPI)—Com­
ponent Removal/Installation section
of
this group.

ROLLOVER VALVE
J9314-167
Fig.
21
Fuel Filter/Fuel Pressure Regulator—5.9L Engine

FUEL
TUBES/LINES/HOSES
AND CLAMPS
Also refer
to
Quick-Connect Fittings
in
this sec­
tion.

WARNING:
THE
FUEL
SYSTEM
IS
UNDER
A
CON­
STANT
PRESSURE
(EVEN WITH
THE
ENGINE
OFF).
BEFORE
SERVICING
ANY
FUEL
SYSTEM
HOSES,

FITTINGS
OR
LINES,
THE
FUEL
SYSTEM
PRES­

SURE
MUST
BE
RELEASED-
REFER
TO
THE
FUEL
PRESSURE
RELEASE
PROCEDURE
IN
THIS

GROUP.

Inspect
all
hose connections such
as
clamps, cou­
plings
and
fittings
to
make sure they
are
secure
and
leaks
are not
present.
The
component should
be re­

placed immediately
if
there
is any
evidence
of
degra­ dation that could result
in
failure.
Avoid contact
of any
fuel tubes/hoses with other
ve­

hicle components that could cause abrasions
or scuff­
ing.
Be
sure that
the
plastic fuel tubes
are
properly
routed
to
prevent pinching
and to
avoid heat sources.

CAUTION:
The
tubes/hoses used
on
fuel
injected

vehicles
are of a
special construction. This
is due
to
the
higher
fuel
pressures
and the
possibility
of

contaminated
fuel
in
this system.
If it is
necessary
to replace these tubes/hoses, only tubes/hoses marked EFM/EFI
may
be
used.

CAUTION:
The
hose clamps used
on
fuel
injected

vehicles
are of a
special rolled edge construction
to
prevent
the
edge
of the
clamp from cutting into
the

hose.
Only these rolled edge
type
clamps
may be

used
in
this system.
All
other types
of
clamps
may

cut into
the
hoses
and
cause high pressure
fuel
leaks.

Use
new
original equipment type hose clamps.
Tighten hose clamps
to 1 N*m (10 in. lbs.)
torque.

QUICK-CONNECT FITTINGS
Also refer
to the
previous Fuel Tubes/Lines/Hoses
and Clamps. Two different types
of
Quick-Connect fittings
are

used
at
several fuel system connections.
One
type
of

fitting will
be
referred
to as a Tab
Type Fitting.
The

other will
be
referred
to as a
Plastic Ring Type fit­
ting.

CAUTION:
Quick-connect fittings
are not
serviced
separately.
Do not
attempt
to
repair damaged quick-
connect fittings
or
fuel
tubes. Replace
the
complete

fuel
tube/quick-connect
fitting
assembly.
TAB
TYPE
FITTING This fitting
is
equipped with
a
retainer
tab
(Figs.

22
or
23) that must
be
released prior
to
disconnecting
the fitting from
the
fuel tube. This type
of
fitting
can

be disassembled either manually
or
with
a
straight
blade screwdriver.
TUBE
END TAB
J9114-167

Fig.
22 Tab
Type
Fitting

14
- 12
FUEL
SYSTEM

•

PULL TAB
RETAINER TAB RETAINER TAB BENT
IN ORIGINAL UPRIGHT DOWN
FOR
POSITION REMOVAL
J9114-168

Fig.
23 Retainer Tabs

MANUAL DISASSEMBLY WARNING:
RELEASE
FUEL
SYSTEM PRESSURE
BEFORE
DISCONNECTING
A
QUICK-CONNECT FIT­
TING.
REFER
TO THE
FUEL
PRESSURE RELEASE
PROCEDURE.

(1) Disconnect negative cable from the battery,
(2) Perform the Fuel Pressure Release Procedure.
Refer to the Fuel Pressure Release Procedure in this section. (3) Bend the retainer tab downward (Fig. 23).

CAUTION:
If the
retainer
tab on the removable
pull

tab is not
bent
down
prior
to disconnecting quick- connect
fitting,
the connector could be
damaged.

(4) While pushing upward on the bottom side of
the pull tab, release the retainer legs by pulling
them away from each other (Fig. 24).
(5) Raise the pull tab until the hooks on the re­
tainer legs clear the stop on the fuel tube fitting (Fig. 25).

PULL Fig.
24 Separating Retainer
Legs Fig.
25 Manually
Disconnecting
Fitting
(6) Pull the fuel tube out of quick-connect fitting
(Fig. 26). (7) Inspect the quick-connect fitting body and re­
tainer for damage. Replace as necessary.
FUEL QUICK CONNECT
TUBE
FITTING

STOP
J9114-171
Fig.
26
Fuel
Tube and
Fitting

(8) Prior to connecting the fuel tube to quick-con­
nect fitting, check condition of tube and clean the
fuel tube and fitting with a lint-free cloth. Lubricate
it with clean engine oil.
(9) Insert the fuel tube into quick-connect fitting
until stop on fuel tube rests against back of fitting. Push retainer down until it locks in place. Pull back
on fuel tube and fitting to be sure of a complete con­
nection.
(10) Connect negative cable to battery.

DISASSEMBLY
WITH
SCREWDRIVER WARNING:
RELEASE
FUEL
SYSTEM PRESSURE
BEFORE
DISCONNECTING
A
QUICK-CONNECT FIT­
TING.
REFER
TO THE
FUEL
PRESSURE RELEASE
PROCEDURE.

•

FUEL
SYSTEM
14 - 13 (1) Disconnect negative cable from the battery.
(2) Perform the Fuel Pressure Release Procedure.
Refer to the Fuel Pressure Release Procedure in this section.
(3) Bend the retainer tab downward.

CAUTION:
If the
retainer
tab on the
removable
pull

tab
is not
bent
down
prior
to
disconnecting
the
quick-connect
fitting,
the
connector
could
be
dam­

aged.

(4) Insert screwdriver tip between connector body
and retainer pull tab (Fig. 27).
RETAINER
SCREWDRIVER

J9114-172

J9114-181

Fig.
29
Disconnecting
Fitting

(9) Prior to connecting fuel tube to quick-connect
fitting, check condition of tube and clean the fuel
tube and fitting with a lint-free cloth. Lubricate it
with clean engine oil.
(10) Insert fuel tube into quick-connect fitting un­
til stop on fuel tube rests against back of fitting.
Push retainer down until it locks in place. Pull back on fuel tube and fitting to be sure of a complete con­
nection.
(11) Connect negative cable to battery.
PLASTIC RING TYPE FITTING
Fig.
27
Disassembly
with
Screwdriver
(5) Turn screwdriver 90 degrees to lift retainer up
(Fig. 28).

RETAINER
PULL
TAB
SCREWDRIVER
J9114-173

Fig.
28
Releasing
Retainer
(6) Raise the pull tab until the hooks on the re­
tainer legs clear the stop on the fuel tube fitting
(Fig. 29). (7) Pull fuel tube out of quick-connect fitting.
(8) Inspect fitting body and retainer for damage.
Replace as necessary.
WARNING:
RELEASE
FUEL
SYSTEM PRESSURE
BEFORE
DISCONNECTING
A
QUICK-CONNECT FIT­
TING.
REFER
TO THE
FUEL
PRESSURE RELEASE PROCEDURE.

This type of fitting contains non-serviceable sealed
O-rings. (1) Disconnect negative cable from the battery.
(2) Perform the Fuel Pressure Release Procedure.
Refer to the Fuel Pressure Release Procedure in this section. (3) To release the fuel tube from the fitting, push
in on the tube while pushing the spring loaded plas­
tic retainer ring into the fitting (Fig. 30). With the
plastic ring depressed, pull the tube from fitting. Af­ ter disconnection, the plastic retainer ring will re­
main on the fitting.
(4) Inspect fitting connector body and plastic re­
tainer ring (Fig. 30) for damage. Replace as neces­ sary.
(5) Prior to connecting fuel tube to quick-connect
fitting, check condition of tube and clean the fuel
tube and fitting with a lint-free cloth. Lubricate it
with clean engine oil.
(6) Insert the fuel tube into quick-connect fitting
(Fig. 30) until a click is felt. Pull back on fuel tube
and fitting to be sure of a complete connection.
(7) Connect negative cable to battery.