Intake Manifold Air Temperature; Spark Plug Cables - Jeep 1997 Grand Cherokee Service Manual

SYNC DISTRIBUTOR GENERATOR ASSEMBLY SIGNAL
8D - 8 IGNITION SYSTEM
DIAGNOSIS AND TESTING (Continued)
Fig. 13 Camshaft Position Sensor—Typical(5.2L/5.9L
Distributor Shown)
(2) Connect the negative (-) voltmeter lead into the
ground wire. For wire identification, refer to Group
8W, Wiring Diagrams.
(3) Set the voltmeter to the 15 Volt DC scale.
(4) 5.2L/5.9L Engines: Remove distributor cap
from distributor (two screws). Rotate (crank) the
engine until the distributor rotor is pointed towards
the rear of vehicle. The movable pulse ring should
now be within the sensor pickup.
(5) 4.0L Engine: Remove distributor cap from
distributor (two screws). Rotate (crank) the engine
until the distributor rotor is pointed to approximately
the 11 o'clock position. The movable pulse ring
should now be within the sensor pickup.
(6) Turn ignition key to ON position. Voltmeter
should read approximately 5.0 volts.
(7) If voltage is not present, check the voltmeter
leads for a good connection.
(8) If voltage is still not present, check for voltage
at the supply wire. For wire identification, refer to
Group 8W, Wiring Diagrams.
(9) If 5 volts is not present at supply wire, check
for voltage at PCM 32-way connector (cavity A-17).
Refer to Group 8W, Wiring for location of connector/
terminal. Leave the PCM connector connected for
this test.
(10) If voltage is still not present, perform vehicle
test using the DRB scan tool.
(11) If voltage is present at cavity A-17, but not at
the supply wire:
(a) Check continuity between the supply wire.
This is checked between the distributor connector
and cavity A-17 at the PCM. If continuity is not
present, repair the harness as necessary.
(b) Check for continuity between the camshaft
position sensor output wire and cavity A-18 at the
PULSE RING POSITION SEN- CAMSHAFT SOR
PCM. If continuity is not present, repair the har-
ness as necessary.
(c) Check for continuity between the ground cir-
cuit wire at the distributor connector and ground.
If continuity is not present, repair the harness as
necessary.
(12) While observing the voltmeter, crank the
engine with ignition switch. The voltmeter needle
should fluctuate between 0 and 5 volts while the
engine is cranking. This verifies that the camshaft
position sensor in the distributor is operating prop-
erly and a sync pulse signal is being generated.
If sync pulse signal is not present, replacement of
the camshaft position sensor is necessary
ENGINE COOLANT TEMPERATURE SENSOR
For an operational description, diagnosis and
removal/installation procedures, refer to Group 14,
Fuel System.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
For an operational description, diagnosis and
removal/installation procedures, refer to Group 14,
Fuel System.

SPARK PLUG CABLES

Check the spark plug cable connections for good
contact at the coil(s), distributor cap towers, and
spark plugs. Terminals should be fully seated. The
insulators should be in good condition and should fit
tightly on the coil, distributor and spark plugs. Spark
plug cables with insulators that are cracked or torn
must be replaced.
Clean high voltage ignition cables with a cloth
moistened with a non-flammable solvent. Wipe the
cables dry. Check for brittle or cracked insulation.
On 5.2L/5.9L V-8 engines, spark plug cable heat
shields are pressed into the cylinder head to sur-
round each spark plug cable boot and spark plug
(Fig. 14). These shields protect the spark plug boots
from damage (due to intense engine heat generated
by the exhaust manifolds) and should not be
removed. After the spark plug cable has been
installed, the lip of the cable boot should have a
small air gap to the top of the heat shield (Fig. 14).
TESTING
When testing secondary cables for damage with an
oscilloscope, follow the instructions of the equipment
manufacturer.
If an oscilloscope is not available, spark plug cables
may be tested as follows:
ZG