(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)
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)
START positions, fuel supply is allowed at the injec-
tion pump.
(1) Disconnect the electrical pigtail connector (test
connector) (Fig. 23) from the main engine wiring har-
ness. Do not disconnect wiring directly at solenoid.
(2) Connect the leads of a voltmeter between a
good ground and the disconnected engine wiring har-
ness.
(3) Turn the key to the ON position. Do not
attempt to start engine.
(4) 12V+ should be observed at wiring harness. If
not, refer to Group 8, Wiring for wiring schematics
and repair as necessary.
(5) T
urn the key to the START position. 12V+ should
be observed at wiring harness. If not, refer to Group 8,
Wiring for wiring schematics and repair as necessary.
The fault may be in the ignition (key) switch.
12V+ must be observed in both the ON and START
positions. If 12V+ was observed, proceed to the next
step.
(6) With key still in the ON position, connect and
disconnect the wiring harness to the solenoid. As this
is done, a clicking noise should be heard coming from
the solenoid. If not, replace solenoid. Refer to Fuel
Shutdown Solenoid in the Removal/Installation sec-
tion of this group for procedures.
HIGH-PRESSURE FUEL LINE LEAK TEST
High±pressure fuel line leaks can cause starting
problems and poor engine performance.
WARNING: DUE TO EXTREME FUEL PRESSURES
OF UP TO 45,000 KPA (6526 PSI), USE EXTREME
CAUTION WHEN INSPECTING FOR HIGH±PRESSURE
FUEL LEAKS. DO NOT GET YOUR HAND, OR ANY
PART OF YOUR BODY NEAR A SUSPECTED LEAK.
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.
Start the engine. Move the cardboard over the
high±pressure fuel lines and check for fuel spray onto
the cardboard (Fig. 24). If a high±pressure line con-
nection is leaking, bleed the system and tighten the
connection. Refer to the Air Bleed Procedure in this
group for procedures. Replace damaged, restricted or
leaking high±pressure 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.
WASTEGATE (TURBOCHARGER)
Refer to Group 11, Exhaust System and Intake
Manifold for information.
SERVICE PROCEDURES
AIR BLEED PROCEDURES
AIR BLEEDING AT FUEL FILTER
A certain amount of air may become trapped in the
fuel system when fuel system components are ser-
viced or replaced. Bleed the system as needed after
fuel system service according to the following proce-
dures.
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.
Some air enters the fuel system when the fuel fil-
ter or injection pump supply line is changed. This
small amount of air is vented automatically from the
injection pump through the fuel drain manifold tubes
if the filter was changed according to instructions.
Ensure the bowl of the fuel filter/water separator is
full of fuel
It may be necessary to manually bleed the system
if:
²The bowl of the fuel filter/water separator is not
partially filled before installation of a new filter
²The injection pump is replaced
Fig. 24 Typical Test for Leaks with Cardboard
14 - 14 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DIAGNOSIS AND TESTING (Continued)
(8) Disconnect the main engine wiring harness
from the glow plugs.
(9) Disconnect the four high±pressure fuel lines
from the fuel injection pump. Also disconnect fuel
lines at the fuel injectors. For procedures, refer to
High±Pressure Fuel Lines in this group. Place a rag
beneath the fittings to catch excess fuel.
(10) Remove plug from timing gear cover.
(11) The ªTop Dead Centerº (TDC) compression fir-
ing stroke must be determined as follows:
(a) Remove the valve cover, refer to Group 9,
Valve Cover Removal/Installation.
(b) Remove the right front tire and splash
shield. Using a socket attached to the end of crank-
shaft, rotate the engine (counterÐclockwise as
viewed from front).
(c) Rotate the engine until cylinder #4 rockers
are in between movement.
(d) Remove rocker arm assembly.
(e) Remove valve spring and keepers.CAU-
TION: When the piston is at TDC there is only
2 mm (.080 thousand) clearance between the
valve and piston.
(f) Let the valve set on top of piston. Install a
dial indicator to the top of the valve stem.
(g) Rotate engine back and forth to find the TDC
position with the indicator on the valve stem. Mark
the damper and timing cover for TDC.
NOTE: On later model 1997 engines, a hole in the
bottom of the clutch housing can be lined up with a
hole in the flywheel, allowing the engine to be held
at TDC with a special alignment tool, part # VM1035.(12) Remove injection pump drive gear nut (Fig.
41) and washer.CAUTION: Be very careful not to
drop the washer into the timing gear cover.
(13) A special 3±piece gear removal tool set
VM.1003 (Fig. 42) must be used to remove the injec-
tion pump drive gear from the pump shaft.
(a) Thread the adapter (Fig. 43) into the timing
cover.
(b) Thread the gear puller into the injection
pump drive gear (Fig. 43). This tool is also used to
hold the gear in synchronization during pump
removal.
(c) Remove the three injection pump±to±gear
cover mounting nuts (Fig. 44).CAUTION: This
step must be done to prevent breakage of the
Fig. 40 Engine Coolant Temperature Sensor
Fig. 41 Removing Pump Drive Gear Nut
Fig. 42 Pump Gear Tools
14 - 20 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
REMOVAL AND INSTALLATION (Continued)
(14) Gauge reading should be at 0.60 mm. If not,
the pump must be rotated for adjustment:
(a) Loosen the three injection pump mounting
nuts at the mounting flanges. These flanges are
equipped with slotted holes. The slotted holes are
used to rotate and position the injection pump for
fuel timing. Loosen the three nuts just enough to
rotate the pump.
(b) Rotate the pumpclockwise(as viewed from
front) until .60 mm is indicated on the dial indica-
tor gauge.
(c) Tighten the three pump mounting nuts to 30
N´m (22 ft. lbs.) torque.
(d) Recheck the dial indicator after tightening
the pump mounting nuts. Gauge should still be
reading 0.60 mm. Loosen pump mounting nuts and
readjust if necessary.
(15) Remove dial indicator and adapter tools.
(16) Install access plug and washer to rear of
injection pump.
(17) Install plug at timing gear cover.
(18) Remove dial indicator from valve stem.
(19) Install valve spring and keepers.
(20) Install rocker arm assembly and tighten nuts.
(21) Install and connect the four high±pressure
fuel lines to the fuel injection pump. Also connect
fuel lines at the fuel injectors. For procedures, refer
to High±Pressure Fuel Lines in this group.
(22) Install electrical connector at engine coolant
temperature sensor.
(23) Connect electrical connector at fuel shutdown
solenoid.(24) Connect the main engine wiring harness to
the glow plugs.
(25) Connect the fuel timing solenoid pigtail har-
ness to the engine wiring harness.
(26) Connect the overflow valve/banjo fitting (fuel
return line assembly). Replace copper gaskets before
installing.
(27) Connect the rubber fuel return and supply
hoses to metal lines at pump. Tighten hose clamps to
2 N´m (20 in. lbs.) torque.
(28) Install generator assembly.
(29) Install engine accessory drive belt. Refer to
Group 7, Cooling System for procedures.
(30) Install negative battery cable to battery.
(31) Start the engine and bring to normal operat-
ing temperature.
(32) Check for fuel leaks.
FUEL INJECTORS
Four fuel injectors are used on each engine. Of these
four, two different types are used. The fuel injector used
on cylinder number one is equipped with a fuel injector
sensor (Fig. 47). The other three fuel injectors are iden-
tical.
Do not place the fuel injector equipped with
the fuel injector sensor into any other location
except the cylinder number one position.
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Thoroughly clean the area around the injector
with compressed air.
(3) Remove the fuel drain hoses (tubes) at each
injector (Fig. 48) being serviced. Each of these hoses
is slip±fit to the fitting on injector.
(4) Remove the high±pressure fuel line at injector
being removed. Refer to High±Pressure Fuel Lines in
this group for procedures.
(5) Remove the injector using special socket tool
number VM.1012A. When removing cylinder number
Fig. 46 Installing Dial Indicator and Special Adapter
Tools
Fig. 47 Fuel Injector SensorÐNumber±1 Cylinder
14 - 22 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
REMOVAL AND INSTALLATION (Continued)
one injector, thread the wiring harness through the
access hole on the special socket (Fig. 49).
(6) Remove and discard the copper washer (seal) at
bottom of injector (Fig. 47).
INSTALLATION
(1) Clean the injector threads in cylinder head.
(2) Install new copper washer (seal) to injector.
(3) Install injector to engine. Tighten to 70 N´m
(52 ft. lbs.) torque.
(4) Install high±pressure fuel lines. Refer to High-
±Pressure Fuel Lines in this group for procedures.
(5) Install fuel drain hoses (tubes) to each injector.
Do not use clamps at fuel drain hoses.
(6) Connect negative battery cable to battery.
(7) Bleed the air from the high±pressure lines.
Refer to the Air Bleed Procedure section of this
group.
FUEL SHUTDOWN SOLENOID
The solenoid is mounted to the rear of the injection
pump (Fig. 50).
REMOVAL
(1) Thoroughly clean the area around the solenoid
with compressed air.
(2) Disconnect the fuel return line and banjo fit-
ting above the solenoid by removing (un±threading)
the overflow valve (Fig. 50). Place a towel below the
valve before removal. Discard old sealing washers
after removal.
(3) Disconnect the electrical connector nut (Fig.
50).
(4) Remove wiring at solenoid.
(5) Remove solenoid from injection pump.
INSTALLATION
(1) Install solenoid into injection pump.
(2) Install wiring and nut at solenoid.
(3) Install new sealing washers to banjo fitting.
(4) Install overflow valve, banjo fitting and fuel
return line to pump.
(5) Bleed air from system. Refer to Air Bleed Pro-
cedures in this section of the group.
FUEL TANK
REMOVAL
(1) Disconnect negative cable from battery.
(2) Insert fuel siphon hose into fuel filler neck and
push it into the tank.
(3) Drain fuel tank dry into holding tank or a
properly labeleddieselsafety container.
Fig. 48 Fuel InjectorÐTypical
Fig. 49 Wiring Harness Through Socket
Fig. 50 Fuel Shutdown Solenoid Location
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 23
REMOVAL AND INSTALLATION (Continued)
Connect the DVM between the center and sensor
ground terminal. Refer to Group 8W - Wiring Dia-
grams for correct pinout.
With the ignition switch in the ON position, check
the output voltage at the center terminal wire of the
connector. Check the output voltage at idle and at
Wide-Open-Throttle (WOT). At idle, TPS output volt-
age should be approximately 0.38 volts to 1.2 volts.
At wide open throttle, TPS output voltage should be
approximately 3.1 volts to 4.4 volts. The output volt-
age should gradually increase as the throttle plate
moves slowly from idle to WOT.
Check for spread terminals at the sensor and PCM
connections before replacing the TPS.
THROTTLE BODY MINIMUM AIR FLOW
(1) Turn ignition key to Off.
(2) D
isconnect the PCV valve hose from the intake
manifold nipple (Fig. 31). Cap the PCV vacuum nipple.
(3) Disconnect purge hose from the nipple on the
throttle body (Fig. 32).(4) Use a piece of hose to attach Air Metering Ori-
fice 6457 (0.125 in. orifice) to the purge nipple on the
throttle body (Fig. 33).
(5) Ensure that all accessories are off.
(6) Connect the DRB scan tool to the data link
connector inside the passenger compartment.
(7) Run engine in Park or Neutral until the cooling
fan has cycled on and off at least once (180ÉF).
(8) Using the DRB scan tool, access Minimum Air-
flow Idle Speed.
(9) The following will then occur:
²Idle air control motor will fully close
²Idle spark advance will become fixed
²PCM will go open loop enriched
²DRB scan tool displays engine RPM
(10) If idle RPM is within the range shown in the
Idle Specification chart, throttle body minimum air-
flow is set correctly.IDLE SPECIFICATION Ð2.0L ENGINE
Odometer Reading Idle RPM
Below 1000 Miles...............550±1300 RPM
Above 1000 Miles...............600±1300 RPM
(11) If idle RPM is above specifications, use the
DRB scan tool to check idle air control motor opera-
tion. If idle air control motor is OK, replace throttle
body. If idle air flow is below specification, shut off
the engine and clean the throttle body as follows:
WARNING: CLEAN THROTTLE BODY IN A WELL
VENTILATED AREA. WEAR RUBBER OR BUTYL
GLOVES, DO NOT LET MOPAR PARTS CLEANER
COME IN CONTACT WITH EYES OR SKIN. AVOID
INGESTING THE CLEANER. WASH THOROUGHLY
AFTER USING CLEANER.
Fig. 31 PCV Vacuum Nipple
Fig. 32 Purge Hose
Fig. 33 Orifice 6457 Attached to Purge Nipple
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 41
DIAGNOSIS AND TESTING (Continued)