Chrysler Town, Dodge Caravan. Manual — part 1105
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AIR IN FUEL
SYSTEM
Air will enter the fuel system whenever fuel supply
lines, separator filters, injection pump, high-pressure
lines or injectors are removed or disconnected. Air
trapped in the fuel system can result in hard start-
ing, a rough running engine, engine misfire, low
power, excessive smoke and fuel knock.
Inspect the fuel system from the fuel tank to the
injectors for loose connections (Refer to 14 - FUEL
SYSTEM - WARNING). Leaking fuel is an indicator
of loose connections or defective seals. Air can also
enter the fuel system between the fuel tank and the
fuel/lift pump. Inspect the fuel tank and fuel lines for
damage that might allow air into the system.
With the DRBIII
t connected to the vehicle, select
Engine and the select Sensor Display. Page down to
view Fuel Pressure Set Point and Actual Fuel Pres-
sure. Start the engine and observe the Fuel Pressure
Set Point and the Actual Fuel Pressure. If the Actual
Fuel Pressure Oscillates above and below the Fuel
Pressure Set Point in a regular cycle, perform the
Fuel System Air Purge procedure (Refer to 14 -
FUEL SYSTEM - STANDARD PROCEDURE).
If the Actual Fuel Pressure gradually drops below
the Fuel Pressure Set Point then spikes well above
the Fuel Pressure Set Point, replace the fuel pres-
sure solenoid (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/FUEL
PRESSURE
SOLENOID
-
REMOVAL), then perform the Fuel System Air Purge
procedure (Refer to 14 - FUEL SYSTEM - STAN-
DARD PROCEDURE).
DIAGNOSIS AND TESTING - FUEL SUPPLY
RESTRICTIONS
LOW-PRESSURE LINES
Fuel supply line restrictions or a defective fuel/lift
pump can cause starting problems and prevent
engine from accelerating. The starting problems
include; low power and/or white fog like exhaust.
Test all fuel supply lines for restrictions or block-
age. Flush or replace as necessary. Purge fuel system
of air once a fuel supply line has been replaced (Refer
to 14 - FUEL SYSTEM - STANDARD PROCEDURE).
HIGH-PRESSURE LINES
CAUTION: High pressure lines cannot contact each
other or other components. Do not attempt to weld
high-pressure fuel lines or to repair lines that are
damaged. High pressure lines must be replaced at
each disassembly. Use only recommended lines
when replacement of high-pressure fuel line is nec-
essary.
Restricted (kinked or bent) high-pressure lines can
cause starting problems, poor engine performance,
engine mis-fire and white smoke from exhaust (Refer
to 14 - FUEL SYSTEM - WARNING).
DIAGNOSIS AND TESTING - FUEL DELIVERY
SYSTEM
NOTE: Air Intrusion is the most common failure of a
fuel system. If air intrusion is suspect, perform the
Fuel System Air Purge procedure first.(Refer to 14 -
FUEL SYSTEM - STANDARD PROCEDURE).
CONDITION
POSSIBLE CAUSES
CORRECTION
No Start/Hard Start/Start
and Stall
Contaminated Fuel
Drain, Flush and Refill Fuel System
Low Fuel Pressure
Check Fuel/Lift Pump Pressure.
Refer to Fuel Pump Pressure Test in
this section
Restricted Fuel Filter
Replace Fuel Filter
Fuel/Lift Pump Relay Inoperative
Test Fuel/Lift Pump Relay, refer to
Fuel/Lift Pump Relay in this section.
Fuel Heater Inoperative
Test Fuel Heater and circuitry. Refer
to Fuel Heater in this section.
Restricted or Leaking Fuel Lines
Inspect/ Replace necessary fuel
line(s), perform Fuel System Air
Purge
Stored Diagnostic Trouble Codes
Refer to the appropriate Diagnostic
Service Manual
RG
FUEL SYSTEM
14 - 3
FUEL SYSTEM 2.5L TURBO DIESEL (Continued)
CONDITION
POSSIBLE CAUSES
CORRECTION
Stalls Under Aggressive
Maneuvers/Loss Of Fuel
Pressure
Restricted or Damaged Fuel Tank
Siphon Filter
Replace Fuel Tank Siphon Filter
Contaminated Fuel
Drain, Flush and Refill Fuel System
Damaged Fuel Tank
Replace Fuel Tank
Restricted Fuel Filter
Replace Fuel Filter
Stored Diagnostic Trouble Codes
Refer to the appropriate Diagnostic
Service Manual
Cannot Refill Fuel
Tank/Excessive Pressure
in Fuel Tank When Cap Is
Removed
Sticking or Damaged Fuel Tank
Fill/Vent Valve, Hose or Lines
Inspect, Repair Vent Hose and
Lines, Replace Fuel Tank
STANDARD PROCEDURE
STANDARD PROCEDURE - FUEL TRANSFER
PUMP PRESSURE TEST
NOTE: Use a shop towel to capture any fuel spill-
age.
(1) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(2) Connect a fuel pump pressure gauge to the air
purge valve (Fig. 2).
(3) Turn ON the ignition (fuel/lift pump should run
for approximately 5 seconds).
(4) Observe the fuel pressure gauge, fuel pressure
should read between 0.8 -1.2 bar (13 - 17 psi.).
If fuel pressure is outside of specification, review
the following list of possible causes:
• Restricted fuel filter.
• Stored DTC’s.
• Defective fuel/lift pump relay.
• Defective fuel/lift pump. (Refer to 14 - FUEL
SYSTEM/FUEL
DELIVERY/FUEL
TRANSFER
PUMP - DIAGNOSIS AND TESTING).
• Open fuel/lift pump relay Ignition positive cir-
cuit.
• Open fuel/lift pump ignition positive circuit.
• High resistance, fuel/lift pump ground.
STANDARD PROCEDURES - DRAINING WATER
FROM FUEL FILTER
Refer to Fuel Filter/Water Separator removal/in-
stallation for procedures.
STANDARD PROCEDURE - FUEL SYSTEM AIR
PURGE
(1) Remove engine cover (Refer to 9 - ENGINE
COVER - REMOVAL).
(2) Remove cap from air purge fitting on the fuel
supply line. This fitting is located just behind the
alternator next to the engine oil fill tube. (Fig. 3).
(3) Attach a hose of about 1 or 2 meters to this fit-
ting using an appropriate connector.
(4) Direct the end of the hose into an appropriate
fuel container.
(5) Turn the ignition to the “ON” position, Do not
crank the engine. Keep key on until about 1 liter of
fuel has been pumped into the container. Make sure
the hose remains below the level of fuel in the
container while the key is in the ON position.
Fig. 2 AIR PURGE VALVE
1 - AIR PURGE VALVE CAP
2 - AIR PURGE VALVE
3 - ALTERNATOR
4 - ENGINE FRONT COVER
14 - 4
FUEL SYSTEM
RG
FUEL SYSTEM 2.5L TURBO DIESEL (Continued)
NOTE: The fuel pump will only run for 30 — 45 sec-
onds. It may be necessary to cycle the key to the
OFF then ON position several times to pump
approximately 1 liter of fuel.
(6) While keeping end of hose below fuel level in
container, turn the ignition “OFF”.
(7) Remove hose from air purge fitting and replace
cap.
(8) Install engine cover (Refer to 9 - ENGINE
COVER - INSTALLATION).
STANDARD PROCEDURES - CLEANING FUEL
SYSTEM COMPONENTS
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines, fuel rail, and fuel injection
pump. Very tight tolerances are used with these
parts. Dirt contamination could cause rapid part
wear and possible plugging of fuel injector nozzle
tip holes. This in turn could lead to possible engine
misfire. Always wash/clean any fuel system compo-
nent thoroughly before disassembly and then air
dry. DO NOT wire brush injector nozzles when
cleaning. Cap or cover any open part after disas-
sembly. Before assembly, examine each part for
dirt, grease or other contaminants and clean if nec-
essary. When installing new parts, lubricate them
with clean engine oil or clean diesel fuel only.
SPECIFICATIONS - TORQUE
2.5L DIESEL - TORQUE SPECIFICATIONS
DESCRIPTION
N·m
Ft. Lbs.
In. Lbs.
Crankshaft Position
Sensor Bolt
10.8
8
96
Boost Pressure / Intake
Air Temperature Sensor
Bolts
5.4
—
48
Fuel Pump Nuts
27.5
21
—
Fuel Line Fittings at Pump
27.5
21
—
Fuel Pump Sprocket Nut
88.3
65
—
Fuel Injector Retaining
Bolts
32.4
24
—
High Pressure Fuel Lines
22
17
194
Fuel Rail Bolts
27.5
21
—
Fig. 3 AIR PURGE VALVE
1 - AIR PURGE VALVE CAP
2 - AIR PURGE VALVE
3 - ALTERNATOR
4 - ENGINE FRONT COVER
RG
FUEL SYSTEM
14 - 5
FUEL SYSTEM 2.5L TURBO DIESEL (Continued)
FUEL DELIVERY
TABLE OF CONTENTS
page
page
FUEL RAIL
. . . . . . . . . . . . . . . . . . . . . . . . . . 6
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
. . . . . . . . . . . . . . . . . . . 6
. . . . . . . . . . . . . . . . 7
FUEL FILTER / WATER SEPARATOR
. . . . . . . . . . . . . . . . . . . . . . . . . . 7
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
. . . . . . . . . . . . . . . . 8
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
. . . . . . . . . . . . . . . . . . . . . . . . 9
FUEL INJECTION PUMP
. . . . . . . . . . . . . . . . . . . . . . . . . . 9
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
. . . . . . . . . . . . . . . . . . . . . . . . . 10
FUEL LINES
. . . . . . . . . . . . . . . . . . . . . . . . 11
DESCRIPTION - HIGH PRESSURE FUEL
LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
OPERATION - HIGH PRESSURE FUEL LINES
. . . . . . . . . . . . . . . . 12
FUEL/LIFT PUMP RELAY
. . . . . . . . . . . . . . . . . . . . . . . . . 13
. . . . . . . . . . . . . . . . . . . . . . . . . . . 13
FUEL/LIFT PUMP
. . . . . . . . . . . . . . . . . . . . . . . . . 13
. . . . . . . . . . . . . . . . . . . . . . . . . . . 13
DIAGNOSIS AND TESTING - FUEL/LIFT PUMP
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
. . . . . . . . . . . . . . . . . . . . . . . . . 14
WATER IN FUEL SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 14
. . . . . . . . . . . . . . . . . . . . . . . . . . . 14
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
. . . . . . . . . . . . . . . . . . . . . . . . . 14
FUEL HEATER RELAY
. . . . . . . . . . . . . . . . . . . . . . . . . 14
. . . . . . . . . . . . . . . . . . . . . . . . . . . 14
FUEL HEATER
. . . . . . . . . . . . . . . . . . . . . . . . . 15
. . . . . . . . . . . . . . . . . . . . . . . . . . . 15
DIAGNOSIS AND TESTING - FUEL HEATER
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
. . . . . . . . . . . . . . . . . . . . . . . . . 16
FUEL RAIL
DESCRIPTION
The fuel rail is mounted to the cylinder head cover/
intake manifold (Refer to 14 - FUEL SYSTEM -
WARNING) (Fig. 1).
OPERATION
WARNING:: HIGH - PRESSURE LINES DELIVER DIE-
SEL FUEL UNDER EXTREME PRESSURE FROM
THE INJECTION PUMP TO THE FUEL INJECTORS.
THIS MAY BE AS HIGH AS 1600BAR (23,200 PSI.).
USE EXTREME CAUTION WHEN INSPECTING FOR
HIGH - PRESSURE FUEL LEAKS. FUEL UNDER
THIS AMOUNT OF PRESSURE CAN PENETRATE
SKIN CAUSING PERSONAL INJURY OR DEATH.
INSPECT FOR HIGH — PRESSURE FUEL LEAKS
WITH A SHEET OF CARDBOARD. WEAR SAFETY
GOGGLES AND ADEQUATE PROTECTIVE CLOTH-
ING WHEN SERVICING FUEL SYSTEM.
The fuel rail stores the fuel for the injectors at
high pressure. At the same time, the pressure oscil-
lations which are generated due to the high-pressure
pump delivery and the injection of fuel are dampened
by the rail volume.
The fuel rail is common to all cylinders, hence it’s
name “common rail”. Even when large quantities of
fuel are extracted, the fuel rail maintains a constant
inner pressure. This ensures that the injection pres-
sure remains constant from the moment the injector
opens.
REMOVAL - FUEL RAIL
(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(3) Disconnect fuel injector high pressure lines
(Refer to 14 - FUEL SYSTEM - WARNING).
(4) Disconnect fuel rail supply line. (Fig. 2)
(5) Disconnect fuel rail return line. (Fig. 2)
(6) Disconnect fuel rail high pressure sensor con-
nector. (Fig. 2)
14 - 6
FUEL DELIVERY
RG
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