Jeep Cherokee 2000 Service Manual - page 1235
(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
the intake manifold. Refer to Group 11, Exhaust Sys-
tem and Intake Manifold for information.
(21) Be sure that the vacuum hoses to the vacuum
pump are connected and not leaking. The vacuum
pump is located in the front of engine (internal) and
is driven from the crankshaft gear (Fig. 17). Discon-
nect the hose and check for minimum vacuum from
the pump. Refer to Group 5, Brake System for spec-
ifications and procedures.
(22) Be sure that the accessory drive belt is not
damaged or slipping.
(23) Verify there is a good connection at the engine
speed sensor. Refer to the Fuel Injection System in
this section for location of the engine speed sensor
location.
(24) Verify there is a good connection at the Boost
Pressure Sensor, which is a part of the air intake
assembly.
AIR IN FUEL SYSTEM
Air will enter the fuel system whenever the fuel
supply lines, fuel filter/water separator, fuel filter
bowl, injection pump, high–pressure lines or injectors
are removed or disconnected. Air will also enter the
fuel system whenever the fuel tank has been run
empty.
Air trapped in the fuel system can result in hard
starting, a rough running engine, engine misfire, low
power, excessive smoke and fuel knock. After service
is performed, air must be bled from the system
before starting the engine.
Inspect the fuel system from the fuel tank to the
injectors for loose connections. Leaking fuel is an
indicator of loose connections or defective seals. Air
can also enter the fuel system between the fuel tank
and the injection pump. Inspect the fuel tank and
fuel lines for damage that might allow air into the
system.
For air bleeding, refer to Air Bleed Procedure in
the Service Procedures section of this group.
FUEL HEATER RELAY TEST
The fuel heater relay is located in the Power Dis-
tribution Center (PDC). Refer to Relays—Operation/
Fig. 16 Engine Coolant Temperature Sensor
Location
1 – PCM ENGINE COOLANT TEMPERATURE (ECT) SENSOR
2 – ECM ENGINE COOLANT TEMPERATURE (ECT) SENSOR
3 – ECM ECT SENSOR HARNESS CONNECTOR
4 – PCM ECT SENSOR HARNESS CONNECTOR
Fig. 17 Vaccum Pump at Front of Engine
1 – VACUUM PUMP
2 – CAMSHAFT
3 – INJECTION PUMP
4 – TIMING MARKS
5 – OIL PUMP
6 – CRANKSHAFT
XJ
FUEL SYSTEM—2.5L DIESEL ENGINE
14 - 9
DIAGNOSIS AND TESTING (Continued)