Chrysler Town, Dodge Caravan. Manual — part 1108
FUEL HEATER
DESCRIPTION
The fuel heater is incorporated within the Fuel Fil-
ter/Water Separator, which is located under the vehi-
cle in front of the rear axle assembly. It’s purpose is
to keep the fuel at a suitable temperature range to
improve cold starting, cold driveability and cold
exhaust emissions.
OPERATION
Fused battery positive voltage is supplied to the
fuel heater relay at all times through the Integrated
Power Module (IPM). Fused ignition positive voltage
is supplied to the fuel heater relay through the IPM.
The fuel heater is grounded through the ECM. When
the ignition switch is in Run or Start position, the
fuel heater relay contacts close and supply power to
the fuel heater. The fuel heater acts as a thermister
(resistance varies with temperature). If the fuel tem-
perature is 8°C (46°F) or below the heater turns on
until the temperature of the fuel reaches 25°C (76°F)
at which time the heater turns off. (Fig. 13).
Fig. 13 FUEL FILTER/WATER SEPARATOR
1 - FUEL/LIFT PUMP RETAINING BOLTS
2 - FUEL/LIFT PUMP
3 - FUEL FILTER/WATER SEPARATOR HOUSING
4 - FUEL HEATER
5 - CHECK BALL
6 - O-RING
7 - FLOW DIVERTER
8 - FUEL FILTER
9 - O-RING
10 - FUEL FILTER BOWL ASSEMBLY
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FUEL DELIVERY
14 - 15
DIAGNOSIS AND TESTING - FUEL HEATER
The fuel heater element only operates between 8°C
(46°F) and 24°C (76°F).
CONDITION
POSSIBLE CAUSES
CORRECTION
Fuel Heater Inoperative
Open or shorted battery positive
circuit to fuel heater relay.
Test and repair circuit as
required.
Open or shorted ignition positive
voltage circuit to fuel heater relay.
Test and repair circuit as
required.
Open or shorted fuel heater relay
ground circuit.
Test and repair circuit as
required.
Open or shorted fuel heater relay
output circuit.
Test and repair circuit as
required.
Faulty fuel heater relay
Test and replace as necessary.
Faulty fuel heater
Test and replace as necessary.
Faulty ECM
Test and replace as necessary.
REMOVAL
(1) The Fuel Heater is part of the Fuel Filter/Wa-
ter Separator. Refer to the Fuel Filter/Water Separa-
tor Replacement Procedure (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY/FUEL FILTER / WATER
SEPARATOR - REMOVAL).
INSTALLATION
(1) The Fuel Heater is part of the Fuel Filer/Water
Separator. Refer to the Fuel Filter/Water Separator
Installation Procedure (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL FILTER / WATER SEPA-
RATOR - INSTALLATION).
14 - 16
FUEL DELIVERY
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FUEL HEATER (Continued)
FUEL INJECTION
TABLE OF CONTENTS
page
page
FUEL INJECTION
STANDARD PROCEDURE - TESTING FUEL
. . . . . . . . . . . . . . . . . . . . . . . . . . 17
FUEL PRESSURE SOLENOID
. . . . . . . . . . . . . . . . . . . . . . . . . 18
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
. . . . . . . . . . . . . . . . . . . . . . . . . 18
FUEL INJECTOR
. . . . . . . . . . . . . . . . . . . . . . 19
. . . . . . . . . . . . . . . . . . . . . . . . . . . 19
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
. . . . . . . . . . . . . . . . . . . . . . . . . 20
ACCELERATOR PEDAL POSITION SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 21
. . . . . . . . . . . . . . . . . . . . . . . . . . . 21
REMOVAL - PEDAL POSITION SENSOR (LHD)
INSTALLATION - PEDAL POSITION SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
BOOST PRESSURE SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 22
. . . . . . . . . . . . . . . . . . . . . . . . . . . 22
PRESSURE/INTAKE AIR TEMPERATURE
SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
INTAKE AIR TEMPERATURE SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 22
. . . . . . . . . . . . . . . . . . . . . . . . . . . 23
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
. . . . . . . . . . . . . . . . . . . . . . . . . 23
CRANKSHAFT POSITION SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 23
. . . . . . . . . . . . . . . . . . . . . . . . . . . 23
MASS AIR FLOW (MAF) SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 23
. . . . . . . . . . . . . . . . . . . . . . . . . . . 23
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
. . . . . . . . . . . . . . . . . . . . . . . . . 24
FUEL INJECTION
STANDARD PROCEDURE - TESTING FUEL
INJECTORS
NOTE: The fuel pump pressure must be between
0.8 and 1.2 bar (13–17 psi), and engine must be at
operating temperature, engine coolant 80°C (176°F).
(1) (Refer to 14 - FUEL SYSTEM - WARNING).
Run engine until operating temperature is obtained.
(2) Turn Off the ignition.
(3) Disconnect the fuel injector fuel return hose at
the return hose tee directly behind the generator,
next to the air purge fitting, leaving the return hose
to the high pressure injection pump connected to the
pump.
(4) Block off fuel return line to high pressure injec-
tion pump.
(5) Connect a hose to the return hose tee and place
it in a suitable container.
(6) Start the engine and measure the return fuel
for 1 minute at idle.
NOTE: If the quantity of fuel is above 100ml. it
means one or more of the fuel injectors has a prob-
lem.
(7) If the measured quantity is above 100ml, dis-
connect each individual injector and measure the
quantity of return fuel into the container.
NOTE: Make sure to block off the fuel return hose
at each individual fuel injector before taking a mea-
surement.
(8) Replace the fuel injector that has a return rate
above 25ml. for one minute at idle(Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/FUEL INJEC-
TOR - REMOVAL).
(9) If the test does not give a positive result, dis-
connect the fuel return line at the fuel rail. If fuel is
present, replace the fuel rail (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY/FUEL RAIL - REMOV-
AL).
(10) Perform the fuel system air purge procedure
after replacing any components (Refer to 14 - FUEL
SYSTEM - STANDARD PROCEDURE).
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FUEL INJECTION
14 - 17
FUEL PRESSURE SOLENOID
DESCRIPTION
The fuel pressure solenoid monitors the low pres-
sure fuel supply to the high pressure injection pump.
The readings along with the Fuel Pressure Sensor
readings are used by the ECM to determine and cal-
culate fuel system pressure under all driving condi-
tions (Fig. 2).
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(3) Lift up on the power steering pump reservoir,
and remove it from it’s mounting. Place the reservoir
aside.
(4) (Refer to 14 - FUEL SYSTEM - WARNING).
Thoroughly clean the high pressure fuel injection
pump around the area of the fuel pressure solenoid
and use compressed air to dry (Fig. 2).
(5) Disconnect the fuel pressure solenoid electrical
connector (Refer to 14 - FUEL SYSTEM - WARN-
ING).
(6) Remove the screw attaching the solenoid to the
pump (Refer to 14 - FUEL SYSTEM - WARNING).
(7) Grab the fuel pressure solenoid, twist, and pull
back to remove the solenoid from the pump (Refer to
14 - FUEL SYSTEM - WARNING).
NOTE: DO NOT use mechanical implements to
remove dirt and debris from the injection pump
bores or mating surfaces.
(8) Use a clean, lint free cloth to remove any
debris from the bores and mating surfaces of the
injection pump.
INSTALLATION
(1) Inspect O-rings on the new pressure solenoid
for any damage and ensure that the O-rings are
seated properly (Refer to 14 - FUEL SYSTEM -
WARNING).
(2) Coat both O-rings with clean engine oil or die-
sel fuel.
NOTE: If pressure solenoid is pressed in at an
angle, the O-rins may be damaged, resulting in fuel
leakage or high pressure injection pump malfunc-
tion.
Fig. 1 DIESEL FUEL SYSTEM COMPONENTS
1 - HIGH PRESSURE FUEL INJECTION PUMP
2 - FUEL PRESSURE SOLENOID
3 - AIR PURGE FITTING
4 - FUEL INJECTOR FUEL RETURN HOSE TEE
5 - HIGH PRESSURE FUEL SUPPLY LINE
6 - FUEL INJECTOR
7 - FUEL RAIL
8 - FUEL RAIL PRESSURE SENSOR
9 - FUEL RAIL RETURN LINE
Fig. 2 FUEL PRESSURE SOLENOID
1 - FUEL RETURN LINE
2 - HIGH PRESSURE FUEL INJECTION PUMP
3 - FUEL PRESSURE SOLENOID
4 - ACCESSORY BRACKET
14 - 18
FUEL INJECTION
RG
FUEL INJECTION (Continued)
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