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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)