GMC 1989 Light Duty Truck, Repair Manual, Page: 691 / 998

DISTRIBUTORS 6D5-11
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Figure 25— Removing the Roll Pin
INSPECTION AND
ELECTRICAL TESTS
Inspect
Cap for cracks or tiny holes. Replace the cap if it is
damaged at all.
Metal term inals in the cap for corrosion. Scrape them
clean with a knife or replace the cap.
Rotor for wear or burning at the outer term inal. The
presence of carbon on the term inal indicates rotor
wear and the need for replacement.
Shaft for shaft-to-bushing looseness. Insert the shaft
in the housing. If the shaft wobbles, replace the hous­
ing and/or shaft.
Housing for cracks or damage.
Measure
Tools Required:
J 24642-F Module Tester
Voltage of the Hall Effect switch (if equipped).
• C onnect a 12 volt battery and voltm eter as
shown in figure 17.
• With a knife blade inserted and held against the
magnet, the voltm eter should read within 0.5
volts of the battery voltage. If not, replace the
switch.
• Remove the knife blade. The voltm eter should
read less than 0.5 volts. If not, replace the
switch.
Resistance of the pickup coil with an ohm meter.
• Connect an ohm m eter to either pickup coil lead
and the housing as shown in figure 27, step 1.
The reading should be infinite. If not, replace
the coil.
• Connect an ohm m eter to both pickup coil leads
as shown in figure 27, step 2. Flex the leads by
hand at the coil and the connector to locate any
interm ittent opens. The ohm m eter should read
a constant unchanging value in the 500 to 1500
ohm range. If not, replace the coil.
Electrical perform ance of the module. The module
can only be checked with an approved module tester,
such as J 24642 or equivalent. Follow the directions
exactly that come with the tester.
Resistance of the ignition coil with an ohm meter.
• C onnect the ohm m eter as shown in figure 28,
step 1. Use the high scale. The reading should
be infinite. If not, replace the coil.
• Connect the ohm m eter as shown in step 2. Use
the low scale. The reading should be very low or
zero. If not, replace the coil.
• Connect the ohm m eter as shown in step 3. Use
the high scale. The meter should not read infi­
nite. If it does, replace the coil.
ASSEMBLY OF DISTRIBUTORS
WITH SEPARATE COILS
DISTRIBUTORS WITH SEALED MODULE
CONNECTORS (Figure 3)
Install or Connect (Figure 23 and 24)
Lubricate
• Bottom of the m odule and the module rest pad
in the housing with silicone grease or an equiva­
lent heat transfer substance.
N O TIC E: Be sure to th o ro u g h ly c o a t th e b o tto m
o f the m o d u le . Failure to d o so c o u ld re s u lt in
h e a t d am ag e to th e m o d u le .
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Module (14) to the housing (30) with two screws.
Pickup coil (11).
• Fit the tab on the bottom of the coil into the
anchor hole in the housing.
Pickup coil w iring connector to the module.
• Make sure the locking tab is in place.
Shield (50) onto the coil.
Retainer (49) onto the shield.
Shaft assem bly (26) into the housing (30).
Spring retainer (52), spring (51), w asher and driven
gear (29) onto the bottom of the shaft.
• Align the marks on the driven gear, housing,
and shaft assembly.
Roll pin (27) into the gear.
Spin the shaft and make sure the teeth on the shaft
assem bly do not touch the pole piece.
Rotor (10) onto the shaft.
• Fit the tab in the rotor into the slot on the shaft.
Cap (23) to the housing with screws and washers.
DISTRIBUTORS W ITHO UT SEALED CONNECTOR
(Figure 26)
Install or Connect
• Lubricate
• Bottom of the module and the m odule rest pad
in the housing with silicone grease or an equiva­
lent heat transfer substance.
NO TIC E: Be sure to th o ro u g h ly c o a t th e b o tto m
o f the m o d u le . Failure to do so c o u ld resu lt in
h e a t d am ag e to th e m o d u le.