Jeep 1996 Grand Cherokee Service Manual - page 279
IGNITION TIMING
NOTE: Base (initial) ignition timing is NOT adjust-
able on any 4.0L/5.2L engine. Do not attempt to
adjust ignition timing by rotating the distributor.
NOTE: On 4.0L 6–cylinder engines, do not attempt
to modify the slotted fork on the distributor housing
to get distributor rotation. Distributor position will
have no effect on ignition timing.
All ignition timing functions are controlled by the
powertrain control module (PCM). For additional
information, refer to the appropriate Powertrain
Diagnostics Procedures service manual for operation
of the DRB Scan Tool.
MAP SENSOR
For an operational description, diagnosis or remov-
al/ installation procedures, refer to Group 14, Fuel
Systems.
CRANKSHAFT POSITION SENSOR—4.0L ENGINE
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
The sensor is located on the transmission bellhous-
ing at the left/rear side of the engine block (Fig. 14).
(1) Near the rear of the intake manifold, discon-
nect sensor pigtail harness connector from main wir-
ing harness.
(2) Place an ohmmeter across terminals B and C
(Fig. 15). Ohmmeter should be set to 1K-to-10K scale
for this test. The meter reading should be open (no
resistance). Replace sensor if a low resistance is indi-
cated.
CRANKSHAFT POSITION SENSOR—5.2L ENGINES
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
The sensor is located on the top of cylinder block
near the rear of right cylinder head (Fig. 16).
(1) Near the rear of the intake manifold, discon-
nect sensor pigtail harness connector from main wir-
ing harness.
(2) Place an ohmmeter across terminals B and C
(Fig. 15). Ohmmeter should be set to 1K-to-10K scale
for this test. The meter reading should be open (no
resistance). Replace sensor if a low resistance is indi-
cated.
CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the dis-
tributor (Fig. 17) on all engines.
To perform a complete test of this sensor and its
circuitry, refer to the appropriate Powertrain Diag-
nostics Procedures service manual. To test the sensor
only, refer to the following:
For this test, an analog (non-digital) voltme-
ter is needed. Do not remove the distributor connec-
tor from the distributor. Using small paper clips,
insert them into the backside of the distributor wire
harness connector to make contact with the termi-
nals. Be sure that the connector is not damaged
Fig. 14 Crankshaft Position Sensor Location—4.0L
6-Cyl. Engine
Fig. 15 Crankshaft Position Sensor Connector
8D - 8
IGNITION SYSTEM
ZJ
DIAGNOSIS AND TESTING (Continued)