Jeep 1997 Grand Cherokee Service Manual page 359

ZG
REMOVAL AND INSTALLATION (Continued)
Rotate crankshaft in a clockwise direction, as
viewed from front, until number one cylinder piston
is at top of compression stroke (compression should
be felt on finger with number one spark plug
removed). Then continue to slowly rotate engine
clockwise until indicating mark (Fig. 33) is aligned to
0 degree (TDC) mark on timing chain cover.
(1) Clean top of cylinder block for a good seal
between distributor base and block.
(2) Lightly oil the rubber o-ring seal on the distrib-
utor housing.
(3) Install rotor to distributor shaft.
(4) Position distributor into engine to its original
position. Engage tongue of distributor shaft with slot
in distributor oil pump drive gear. Position rotor to
the number one spark plug cable position.
(5) Install distributor holddown clamp and clamp
bolt. Do not tighten bolt at this time.
(6) Rotate the distributor housing until rotor is
aligned to CYL. NO. 1 alignment mark on the cam-
shaft position sensor (Fig. 34).
(7) Tighten clamp holddown bolt (Fig. 35) to 22.5
N·m (200 in. lbs.) torque.
(8) Connect camshaft position sensor wiring har-
ness to main engine harness.
(9) Install distributor
screws.
(10) Install secondary cables to distributor cap.
(11) Refer to the following, Checking Distributor
Position.
CHECKING DISTRIBUTOR POSITION
To verify correct distributor rotational position,
connect the DRB scan tool to the data link connector.
The data link connector is located in the passenger
compartment, below and to the left of steering col-
umn. Gain access to the SET SYNC screen on the
DRB.
WARNING: WHEN PERFORMING THE FOLLOWING
TEST, THE ENGINE WILL BE RUNNING. BE CARE-
FUL NOT TO STAND IN LINE WITH THE FAN
BLADES OR FAN BELT. DO NOT WEAR LOOSE
CLOTHING.
Follow the directions on the DRB screen and start
the engine. With the engine running, the words IN
RANGE should appear on the screen along with 0°.
This indicates correct distributor position.
If a plus (+) or a minus (-) is displayed next to the
degree number, and/or the degree displayed is not
zero, loosen but do not remove the distributor hold-
down clamp bolt. Rotate the distributor until IN
RANGE appears on the screen. Continue to rotate
the distributor until achieving as close to 0° as pos-
sible. After adjustment, tighten clamp bolt to 22.5
N·m (200 in. lbs.) torque.
cap. Tighten mounting
The degree scale on the SET SYNC screen of the
DRB is referring to fuel synchronization only. It is
not referring to ignition timing. Because of this,
do not attempt to adjust ignition timing using this
method. Rotating the distributor will have no effect
on ignition timing. All ignition timing values are con-
trolled by the powertrain control module (PCM).
After testing, install air cleaner tube to throttle
body.
DISTRIBUTOR—4.0L ENGINE
All 4.0L distributors contain an internal oil seal
that prevents oil from entering the distributor hous-
ing. The seal is not serviceable.
Factory replacement distributors are equipped with
a plastic alignment pin already installed. The pin is
located in an access hole on the bottom of the distrib-
utor housing (Fig. 36). It is used to temporarily lock
the rotor to the cylinder number 1 position during
installation. The pin must be removed after install-
ing the distributor.
Fig. 36 Plastic Alignment Pin—4.0LEngine
The camshaft position sensor is located in the dis-
tributor on all 4.0L engines (Fig. 37). For removal/in-
stallation procedures, refer to Camshaft Position
Sensor. Distributor removal is not necessary for sen-
sor removal.
Refer to (Fig. 37) for an exploded view of distribu-
tor.
A fork with a slot is supplied on bottom of distrib-
utor housing where the housing base seats against
engine block (Fig. 37). The centerline of the slot
aligns with distributor holddown bolt hole in engine
block. Because of the fork, the distributor cannot be
PLASTIC
IGNITION SYSTEM
MENT PIN ALIGN-
8D - 17