1996 CHRYSLER VOYAGER engine

Actual electric fuel timing (amount of advance) is
accomplished by the fuel timing solenoid mounted to
the bottom of the injection pump (Fig. 5). Fuel timing
will be adjusted by the PCM, which controls the fuel
timing solenoid.
An overflow valve is attached into the fuel return
line at the rear of the fuel injection pump (Fig. 4).
This valve serves two purposes. One is to ensure that
a certain amount of residual pressure is maintained
within the pump when the engine is switched off.
This will prevent the fuel timing mechanism within
the injection pump from returning to its zero posi-
tion. The other purpose is to allow excess fuel to be
returned to the fuel tank through the fuel return
line. The pressure values within this valve are preset
and can not be adjusted.
The fuel injection pump supplies high±pressure
fuel of approximately 45,000 kPa (6526 psi) to each
injector in precise metered amounts at the correct
time.
For mechanical injection pump timing, refer to
Fuel Injection Pump Timing in the Service Proce-
dures section of this group.
FUEL INJECTORS
Fuel drain tubes (Fig. 6) are used to route excess
fuel back to the overflow valve (Fig. 4) at the rear of
the injection pump. This excess fuel is then returned
to the fuel tank through the fuel return line.
The injectors are connected to the fuel injection
pump by the high± pressure fuel lines. A separate
injector is used for each of the four cylinders. An
injector containing a sensor (Fig. 7) is used on thecylinder number one injector. This injector is called
instrumented injector #1 or needle movement sensor.
It is used to tell the PCM when the #1 injector's
internal spring-loaded valve seat has been forced
open by pressurized fuel being delivered to the cylin-
der, which is at the end of its compression stroke.
When the instrumented injector's valve seat is force
open, it sends a small voltage spike pulse to the
PCM. This tells the PCM that the engine is at TDC
on the number one cylinder. It is not used with the
other three injectors.
Fuel enters the injector at the fuel inlet (top of
injector) and is routed to the needle valve bore. When
fuel pressure rises to approximately 15,000±15,800
kPa (2175±2291 psi), the needle valve spring tension
is overcome. The needle valve rises and fuel flows
through the spray holes in the nozzle tip into the
combustion chamber. The pressure required to lift
the needle valve is the injector opening pressure set-
ting. This is referred to as the ªpop-offº pressure set-
ting.
Fuel pressure in the injector circuit decreases after
injection. The injector needle valve is immediately
closed by the needle valve spring and fuel flow into
the combustion chamber is stopped. Exhaust gases
are prevented from entering the injector nozzle by
the needle valve.
A copper washer (gasket) is used at the base of
each injector (Fig. 7) to prevent combustion gases
from escaping.
Fuel injector firing sequence is 1±3±4±2.
FUEL TUBES/LINES/HOSES AND CLAMPSÐLOW-
PRESSURE TYPE
Also refer to the proceeding section on Quick±Con-
nect Fittings.
Inspect all hose connections such as clamps, cou-
plings and fittings to make sure they are secure andFig. 6 Fuel Injectors and Drain Tubes
Fig. 7 Fuel Injector Sensor
14 - 6 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DESCRIPTION AND OPERATION (Continued)

leaks are not present. The component should be
replaced immediately if there is any evidence of deg-
radation that could result in failure.
Never attempt to repair a plastic fuel line/tube or a
quick±connect fitting. Replace complete line/tube as
necessary.
Avoid contact of any fuel tubes/hoses with other
vehicle components that could cause abrasions or
scuffing. Be sure that the fuel lines/tubes are prop-
erly routed to prevent pinching and to avoid heat
sources.
The lines/tubes/hoses are of a special construction.
If it is necessary to replace these lines/tubes/hoses,
use only original equipment type.
The hose clamps used to secure the rubber hoses
are of a special rolled edge construction. This con-
struction is used 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
fuel leaks.
Where a rubber hose is joined to a metal tube
(staked), do not attempt to repair. Replace entire
line/tube assembly.
Use new original equipment type hose clamps.
Tighten hose clamps to 2 N´m (20 in. lbs.) torque.
QUICK-CONNECT FITTINGSÐLOW PRESSURE
TYPE
Different types of quick-connect fittings are used to
attach various fuel system components. These are: a
single-tab type, a two-tab type or a plastic retainer
ring type (Fig. 8). Refer to Quick-Connect Fittings in
the Removal/Installation section for more informa-
tion.
CAUTION: The interior components (o-rings, spac-
ers) of quick-connect fitting are not serviced sepa-
rately, but new pull tabs are available for some
types. Do not attempt to repair damaged fittings or
fuel lines/tubes. If repair is necessary, replace the
complete fuel tube assembly.
HIGH-PRESSURE FUEL LINES
CAUTION: The high±pressure fuel lines must be
held securely in place in their holders. The lines
cannot contact each other or other components. Do
not attempt to weld high±pressure fuel lines or to
repair lines that are damaged. Only use the recom-
mended lines when replacement of high±pressure
fuel line is necessary.
High±pressure fuel lines deliver fuel under pres-
sure of up to approximately 45,000 kPa (6526 PSI)
from the injection pump to the fuel injectors. Thelines expand and contract from the high±pressure
fuel pulses generated during the injection process. All
high±pressure fuel lines are of the same length and
inside diameter. Correct high±pressure fuel line
usage and installation is critical to smooth engine
operation.
WARNING: USE EXTREME CAUTION WHEN
INSPECTING FOR HIGH±PRESSURE FUEL LEAKS.
INSPECT FOR HIGH±PRESSURE FUEL LEAKS WITH
A SHEET OF CARDBOARD. HIGH FUEL INJECTION
PRESSURE CAN CAUSE PERSONAL INJURY IF
CONTACT IS MADE WITH THE SKIN.
FUEL DRAIN TUBES
These rubber tubes are low±pressure type.
Some excess fuel is continually vented from the
fuel injection pump. During injection, a small amount
of fuel flows past the injector nozzle and is not
injected into the combustion chamber. This fuel
drains into the fuel drain tubes (Fig. 9) and back to
the tee banjo fitting, which is connected to the same
line as the overflow valve, which allows a variable
quantity to return to the fuel tank. The overflow
valve is calibrated to open at a preset pressure.
Excess fuel not required by the pump to maintain the
minimum pump cavity pressure is then returned
through the overflow valve and on to the fuel tank
through the fuel return line.
Fig. 8 Plastic Retainer Ring-Type Fitting
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 7
DESCRIPTION AND OPERATION (Continued)

FUEL HEATER
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation. The fuel
heater is located in the bottom plastic bowl of the
fuel filter/water separator (Fig. 10).
The element inside the heater assembly is made of
a Positive Temperature Coefficient (PTC) material,
and has power applied to it by the fuel heater relayanytime the ignition key is in the ªonº position. PTC
material has a high resistance to current flow when
its temperature is high, which means that it will not
generate heat when the temperature is above a cer-
tain value. When the temperature is below 7ÉC (45É
F), the resistance of the PTC element is lowered, and
allows current to flow through the fuel heater ele-
ment warming the fuel. When the temperature is
above 29ÉC (85É F), the PTC element's resistance
rises, and current flow through the heater element
stops.
Voltage to operate the fuel heater is supplied from
the ignition (key) switch and through the fuel heater
relay. Refer to the following Fuel Heater Relay for
additional information.The fuel heater and fuel
heater relay are not controlled by the Power-
train Control Module (PCM).
Current draw for the heater element is 150 watts
at 14 volts (DC).
FUEL HEATER RELAY
Voltage to operate the fuel heater is supplied from
the ignition (key) switch through the fuel heater
relay.The PCM is not used to control this relay.
The fuel heater relay is located in the PDC. The
PDC is located next to the battery in the engine com-
partment (Fig. 11). For the location of the relay
within the PDC, refer to label on PDC cover.
WASTEGATE (TURBOCHARGER)
Refer to Group 11, Exhaust System and Intake
Manifold for information.
Fig. 9 Fuel Drain Tubes
Fig. 10 Fuel Heater Temperature Sensor and
Element LocationFig. 11 Relay Location
14 - 8 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DESCRIPTION AND OPERATION (Continued)

DIAGNOSIS AND TESTING
GENERAL INFORMATION
This section of the group will cover a general diag-
nosis of diesel engine fuel system components.
Diagnostic Trouble Codes:Refer to On-Board
Diagnostics in Group 25, Emission Control System
for a list of Diagnostic Trouble Codes (DTC's) for cer-
tain fuel system components.
The PCM must be tested with the DRBIII scan
tool. The DRBIII should be the first step in any diag-
nosis of engine performance complaints. Refer to the
1997 GS 2.5L Diesel Powertrain Diagnostic Proce-
dures manual for diagnosis and testing of the diesel
engine control system.
VISUAL INSPECTION
A visual inspection for loose, disconnected, or incor-
rectly routed wires and hoses should be made before
attempting to diagnose or service the diesel fuel
injection system. A visual check will help find these
conditions. It also saves unnecessary test and diag-
nostic time. A thorough visual inspection of the fuel
injection system includes the following checks:
(1) Be sure that the battery connections are tight
and not corroded.
(2) Be sure that the 68 way connector is fully
engaged with the PCM (Fig. 12).
(3) Verify that the electrical connections for the
Diesel PCM relay are clean and free of corrosion.
This relay is located in the PDC. For the location ofthe relay within the PDC, refer to label on PDC
cover.
(4) Verify that the electrical connections for the
fuel heater relay are clean and free of corrosion. This
relay is located in the PDC. For the location of the
relay within the PDC, refer to label on PDC cover.
(5) Be sure the electrical connectors at the ends of
the glow plugs (Fig. 13) are tight and free of corro-
sion.
(6) Be sure that the electrical connections at the
glow plug relay are tight and not corroded. The glow
plug relay is located in the engine compartment on
the left±inner fender (Fig. 14).
Fig. 12 PCM LocationÐTypical
Fig. 13 Glow Plug Connector
Fig. 14 Glow Plug Relay Location
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 9

(7) Inspect the starter motor and starter solenoid
connections for tightness and corrosion.
(8) Verify that the electrical connector is firmly
connected to the fuel shutdown solenoid. Inspect the
connector for corrosion or damaged wires. The sole-
noid is mounted to the rear of the injection pump
(Fig. 15).
(9) Verify that the fuel heater electrical connector
is firmly attached to the filter bowl at the bottom of
the fuel filter/water separator. Inspect the connector
for corrosion or damaged wires.
(10) Verify that the electrical pigtail connector
(sensor connector) (Fig. 16) for the fuel injector sen-
sor is firmly connected to the engine wiring harness.
Inspect the connector for corrosion or damaged wires.
This sensor is used on the #1 cylinder injector only.
(11) Verify that the electrical pigtail connector
(sensor connector) (Fig. 17) for the fuel timing sole-
noid is firmly connected to the engine wiring har-
ness. Inspect the connector for corrosion or damaged
wires. The fuel timing solenoid is located on the bot-
tom of the fuel injection pump (Fig. 17).
(12) Inspect for exhaust system restrictions such
as pinched exhaust pipes or a collapsed or plugged
muffler.
(13) Verify that the harness connector is firmly
connected to the vehicle speed sensor (Fig. 18).
(14) Verify turbocharger wastegate operation.
Refer to Group 11, Exhaust System and Intake Man-
ifold Group for information.
(15) Verify that the harness connector is firmly
connected to the engine coolant temperature sensor.The sensor is located on the side of cylinder head
near the rear of fuel injection pump (Fig. 19).
(16) Check for air in the fuel system. Refer to the
Air Bleed Procedure.
(17) Inspect all fuel supply and return lines for
signs of leakage.
(18) Be sure that the ground connections are tight
and free of corrosion. Refer to Group 8, Wiring for
locations of ground connections.
(19) Inspect the air cleaner element (filter) for
restrictions.
(20) Be sure that the turbocharger output hose is
properly connected to the charge air cooler (inter-
cooler) inlet tube. Verify that the charge air cooler
output hose is properly connected to the cooler and
Fig. 15 Fuel Shutdown Solenoid Location
Fig. 16 Fuel Injector Sensor
Fig. 17 Fuel Timing Solenoid
14 - 10 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DIAGNOSIS AND TESTING (Continued)

the intake manifold. Refer to Group 11, Exhaust Sys-
tem and Intake Manifold for information.
(21) Be sure that the vacuum hoses to the vacuum
pump are connected and not leaking. The pump is
located on the front of engine (internal) and is driven
from the crankshaft gear and chain (Fig. 20). Discon-
nect the hose and check for minimum vacuum from
the pump. Refer to Group 5, Brake System for spec-
ifications and procedures.(22) Be sure that the accessory drive belt is not
damaged or slipping.
(23) Verify there is a good connection at the engine
speed sensor. Refer to the Fuel Injection System in
this section for location of the engine speed sensor
location.
(24) Verify there is a good connection at the Mass
Air Flow Sensor, which is a part of the air intake
assembly.
AIR IN FUEL SYSTEM
Air will enter the fuel system whenever the fuel
supply lines, fuel filter/water separator, fuel filter
bowl, injection pump, high±pressure lines or injectors
are removed or disconnected. Air will also enter the
fuel system whenever the fuel tank has been run
empty.
Air trapped in the fuel system can result in hard
starting, a rough running engine, engine misfire, low
power, excessive smoke and fuel knock. After service
is performed, air must be bled from the system
before starting the engine.
Inspect the fuel system from the fuel tank to the
injectors for loose connections. Leaking fuel is an
indicator of loose connections or defective seals. Air
can also enter the fuel system between the fuel tank
and the injection pump. Inspect the fuel tank and
fuel lines for damage that might allow air into the
system.
For air bleeding, refer to Air Bleed Procedure in
the Service Procedures section of this group.
Fig. 18 Vehicle Speed SensorÐTypical
Fig. 19 Engine Coolant Temperature Sensor
Location
Fig. 20 Vacuum Pump at Front of Engine
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 11
DIAGNOSIS AND TESTING (Continued)

FUEL HEATER RELAY TEST
The fuel heater relay is located in the Power Dis-
tribution Center (PDC). Refer to RelaysÐOperation/
Testing in Fuel Ingection System section of this
group for test procedures.
FUEL INJECTOR TEST
The fuel injection nozzels, located on the engine
cylinder head, spray fuel under high pressure into
the individual combustion chambers. Pressurized
fuel, delivered by the fuel injection pump, unseats a
spring-loaded needle valve inside the injector, and
the fuel is atomized as it escapes through the injector
opening into the engine's combustion chamber. If the
fuel injector does not operate properly, the engine
may misfire, or cause other driveability problems.
A leak in the injection pump±to±injector high±pres-
sure fuel line can cause many of the same symptoms
as a malfunctioning injector. Inspect for a leak in the
high±pressure lines before checking for a malfunc-
tioning fuel injector.
WARNING: THE INJECTION PUMP SUPPLIES HIGH-
±PRESSURE FUEL OF UP TO APPROXIMATELY
45,000 KPA (6526 PSI) TO EACH INDIVIDUAL INJEC-
TOR THROUGH THE HIGH±PRESSURE LINES. FUEL
UNDER THIS AMOUNT OF PRESSURE CAN PENE-
TRATE THE SKIN AND CAUSE PERSONAL INJURY.
WEAR SAFETY GOGGLES AND ADEQUATE PRO-
TECTIVE CLOTHING. AVOID CONTACT WITH FUEL
SPRAY WHEN BLEEDING HIGH±PRESSURE FUEL
LINES.
WARNING: DO NOT BLEED AIR FROM THE FUEL
SYSTEM OF A HOT ENGINE. DO NOT ALLOW FUEL
TO SPRAY ONTO THE EXHAUST MANIFOLD WHEN
BLEEDING AIR FROM THE FUEL SYSTEM.
To determine which fuel injector is malfunctioning,
run the engine and loosen the high±pressure fuel line
nut at the injector (Fig. 21). Listen for a change in
engine speed. If engine speed drops, the injector was
operating normally. If engine speed remains the
same, the injector may be malfunctioning. After test-
ing, tighten the line nut to 30 N´m (22 ft. lbs.)
torque. Test all injectors in the same manner one at
a time.
Once an injector has been found to be malfunction-
ing, remove it from the engine and test it. Refer to
the Removal/Installation section of this group for pro-
cedures.
After the injector has been removed, install it to a
bench±mount injector tester. Refer to operating
instructions supplied with tester for procedures.
The opening pressure or ªpopº pressure should be
15,000±15,800 kPa (2175±2291 psi). If the fuel injec-tor needle valve is opening (ªpoppingº) to early or to
late, replace the injector.
FUEL INJECTOR SENSOR TEST
The fuel injector sensor is used only on the fuel
injector for the number±1 cylinder (Fig. 22). It is not
used on the injectors for cylinders number 2, 3, or 4.
To test the sensor, unplug the sensor connector
(Fig. 22) from the engine wiring harness. Check
resistance across terminals. Resistance should be 110
ohms610 ohms at 20ÉC (68ÉF). Replace sensor if
specification cannot be met.
FUEL INJECTION PUMP TEST
The injection pump is not to be serviced or
the warranty may be voided. If the injection
pump requires service, the complete assembly
must be replaced.
Incorrect injection pump timing (mechanical or
electrical) can cause poor performance, excessive
smoke and emissions and poor fuel economy.
Fig. 21 Typical Inspection of Fuel Injector
Fig. 22 Fuel Injector Sensor Location
14 - 12 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DIAGNOSIS AND TESTING (Continued)

A defective fuel injection pump, defective fuel tim-
ing solenoid or misadjusted mechanical pump timing
can cause starting problems or prevent the engine
from revving up. It can also cause:
²Engine surge at idle
²Rough idle (warm engine)
²Low power
²Excessive fuel consumption
²Poor performance
²Low power
²Black smoke from the exhaust
²Blue or white fog like exhaust
²Incorrect idle or maximum speed
The electronically controlled fuel pump has no
mechanical governor like older mechanically con-
trolled fuel pumps. Do not remove the top cover of
the fuel pump, or the screws fastening the wiring
pigtail to the side of the pump.The warranty of
the injection pump and the engine may be void
if those seals have been removed or tampered
with.
FUEL SUPPLY RESTRICTIONS
LOW±PRESSURE LINES
Restricted or Plugged supply lines or fuel filter can
cause a timing fault that will cause the PCM to oper-
ate the engine in a ªLimp Homeº mode. See the
introduction of the Fuel Injection System in this
group for more information on the Limp Home mode.
Fuel supply line restrictions can cause starting prob-
lems and prevent the engine from revving up. The
starting problems include; low power and blue or
white fog like exhaust. Test all fuel supply lines for
restrictions or blockage. Flush or replace as neces-
sary. Bleed the fuel system of air once a fuel supply
line has been replaced. Refer to the Air Bleed Proce-
dure section of this group for procedures.
HIGH±PRESSURE LINES
Restricted (kinked or bent) high±pressure lines can
cause starting problems, poor engine performance
and black smoke from exhaust.
Examine all high±pressure lines for any damage.
Each radius on each high±pressure line must be
smooth and free of any bends or kinks.
Replace damaged, restricted or leaking high±pres-
sure fuel lines with the correct replacement line.
CAUTION: The high±pressure fuel lines must be
clamped securely in place in the holders. The lines
cannot contact each other or other components. Do
not attempt to weld high±pressure fuel lines or to
repair lines that are damaged. Only use the recom-
mended lines when replacement of high±pressure
fuel line is necessary.
FUEL SHUTDOWN SOLENOID TEST
Since diesel fuel injection does not use spark plugs
to start combustion, the only way to stop the engine
is to cut off the fuel supply. This is done with the
Fuel Shutdown Solenoid. If the engine cranks, but
refuses to start, it may be caused by a defective fuel
shutdown solenoid.
The fuel shutdown solenoid is not controlled
or operated by the PCM.Voltage to operate the
solenoid is supplied from the ignition (key) switch.
NOTE: Although the fuel shutdown solenoid is not
operated by the PCM, if the Fuel Shutdown Solenoid
has been disconnected, and the key turned on, the
PCM will sense that the solenoid is not in the circuit,
and will switch to a ªLimp Homeº mode. After recon-
necting the solenoid, the PCM will have to be reset
by clearing the codes with the DRBIII scan tool, or
disconnecting the vehicle's battery for several min-
utes. The DRBIII scan tool is the preferred method
for resetting the PCM. Refer to the 1998 GS 2.5L Die-
sel Powertrain Diagnostic Manual for procedure.
The fuel shutdown (shut±off) solenoid is used to
electrically shut off the diesel fuel supply to the high-
±pressure fuel injection pump. The solenoid is
mounted to the rear of the injection pump (Fig. 23).
The solenoid controls starting and stopping of the
engine regardless of the position of the accelerator
pedal. When the ignition (key) switch is OFF, the sole-
noid is shut off and fuel flow is not allowed to the fuel
injection pump. When the key is placed in the ON or
Fig. 23 Fuel Shutdown Solenoid Location
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 13
DIAGNOSIS AND TESTING (Continued)