Tools Needed To Check And Adjust The Ignition Timing; Automatic Transmission Fluid And Filter Change - Jeep cherokee 1989 Owner's Manual

33.1

Tools needed to check and adjust the ignition timing

Vacuum plugs Vacuum hoses will, i n most cases,
-
have to be disconnected and plugged. Molded plugs
i n various shapes and sizes are available for this
2 Inductive pick-up timing light
concentrated beam o f light when the number one
spark plug fires. Connect the leads according
to the instructions supplied with the light
3 Distributor wrench On some models, the hold-down
bolt for the distributor is difficult to reach and turn with
conventional wrenches or sockets. A special wrench like
this must be used
2 Apply the parking brake and block the wheels to prevent move-
ment of the vehicle. The transmission must be in Park (automatic) or
Neutral (manual).
3 On four-cylinder engines, disconnect and plug the hose connected
to the vacuum advance unit on the distributor and unplug the three
wire connector to the vacuum input switches.
4 Locate the timing marks at the front of the engine (they should be
visible from above after the hood is opened) (see illustration). The
crankshaft pulley or vibration damper has a groove in it and a scale
with notches and numbers is either molded into or attached to the en-
gine's timing cover. Clean the scale with solvent so the numbers are
visible.
5
Use chalk or white paint to mark the groove in the pulleyhibration
damper.
6 Highlight the notch or point on the scale that corresponds to the
ignition timing specification on the Vehicle Emission Control Informa-
tion label.
7 Hook up the timing light, following the manufacturer's instructions
(an inductive pick-up timing light is preferred). Generally, the power
leads are attached to the battery terminals and the pick-up lead is at-
tached to the number one spark plug wire. On four and six-cylinder
engines, the number one spark plug is the very front one. On the V6
engine, the number one spark plug is the front one on the passenger's
side of the engine. Caution: I f an inductive pick-up timing light isn't
available, don't puncture the spark plug wire to attach the timing light
The Motor Manual Guy
Chapter 1 Tune-up and routine maintenance
-
Flashes a bright
33.4
The ignition timing marks are located at the front of
the engine (four-cylinder shown)
pick-up lead. Instead, use an adapter between the spark plug and plug
wire. If the insulation on the plug wire is damaged, the secondary volt-
age will jump to ground at the damaged point and the engine will mis-
fire.
8 Make sure the timing light wires are routed away from the drive-
belts and fan, then start the engine.
9 Allow the idle speed to stabilize, then point the flashing timing light
-
at the timing marks be very careful of moving engine components!
10 The mark on the pulleyhibration damper will appear stationary.
If it's aligned with the specified point on the scale, the ignition timing is
correct.
tributor hold-down bolt and turn the distributor very slowly until the
marks are aligned. Since access to the bolt is tight, a special distribu-
tor wrench may be needed.
12 Tighten the bolt and recheck the timing.
13 Turn off the engine and remove the timing light (and adapter, if
used).
14 Reconnect any components which were disconnected.
34

Automatic transmission fluid and filter change

Refer to illustration 34. 10
1
A t the specified time intervals, the transmission fluid should be
drained and replaced. Since the fluid will remain hot long after driving,
perform this procedure only after the engine has cooled down com-
pletely.
2 Before beginning work, purchase the specified transmission fluid
(see Recornmendedlubricants and fluids at the front of this Chapter)
and a new filter.
Other tools necessary for this job include jackstands to support
the vehicle in a raised position, a drain pan capable of holding at least
eight pints, newspapers and clean rags.
4
Raise the vehicle and support it securely on jackstands.
5 With a drain pan in place, remove the front and side pan mount-
ing bolts.
6
Loosen the rear pan bolts approximately one turn.
If the pan does not loosen and fluid does not begin to drain, carefully
pry the transmission pan loose with a putty knife.
8 Remove the remaining bolts, pan and gasket. Carefully clean the
gasket surface of the transmission to remove all traces of the old gasket
and sealant.
9 Drain the fluid from the transmission pan, clean it with solvent and
dry it with compressed air.
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