Jeep Cherokee 2000 Service Manual - page 1238
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 the fuel filter/water separator is full of
fuel
It may be necessary to manually bleed the system
if:
•
The bowl of the fuel filter/water separator is not
partially filled before installation of a new filter
•
The injection pump is replaced
•
High–pressure fuel line connections are loosened
or lines replaced
•
Initial engine start–up or start–up after an
extended period of no engine operation
•
Running fuel tank empty
FUEL INJECTION PUMP BLEEDING
(1) If the fuel injection pump has been replaced,
air should be bled at the overflow valve before
attempting to start engine.
(a) Loosen the overflow valve (Fig. 21) at the
rear of the injection pump.
(b) Place a towel below the valve.
WARNING: WHEN
CRANKING
THE
ENGINE
TO
BLEED AIR FROM THE INJECTION PUMP, THE
ENGINE MAY START. PLACE THE TRANSMISSION
IN NEUTRAL OR PARK AND SET PARKING BRAKE
BEFORE ENGAGING THE STARTER MOTOR.
CAUTION: Do not engage the starter motor for
more than 30 seconds at a time. Allow 2 minutes
between cranking intervals.
(2) Crank the engine for 30 seconds at a time to
allow air trapped in the injection pump to vent out
the fuel injector drain tubes. Continue this procedure
until the engine starts. Observe the previous WARN-
ING and CAUTION.
(3) Tighten overflow valve.
Fig. 20 Typical Fuel Pressure Test at Injection Pump
1 – FITTING
2 – HIGH PRESSURE LINE
3 – CARDBOARD
Fig. 21 Overflow Valve
1 – FUEL INJECTION PUMP ASSEMBLY
2 – FUEL RETURN LINE
3 – FUEL SUPPLY LINE
4 – FUEL INJECTION PUMP 10–WAY CONNECTOR
5 – TIMING SOLENOID
6 – OVERFLOW VALVE
14 - 12
FUEL SYSTEM—2.5L DIESEL ENGINE
XJ
DIAGNOSIS AND TESTING (Continued)