Mercury MerCruiser MCM 454 Mag MPI Service Manual page 681

GENERAL SYSTEM DIAGNOSTICS
Chart A-7 (5 of 6): Ignition System Check (Continued)
Step
11
12
13
14
15
16
17
Index
Page 5E-88
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Action
1. Disconnect distributor 4-wire
connector.
2. Remove distributor cap.
3. Disconnect pick-up coil con-
nector from the distributor
ignition control module.
4. Connect D\/OM to tach termi-
nal at the 5-wire harness con-
nector and ground.
5. Ignition "ON," engine "OFF".
6. Connect positive (+) end of
a known good 1.5 volt test
battery to the "P" terminal on
the distributor ignition con-
trol module. Observe the
voltage at the tach terminal
as the negative (–) end of
the test battery is momen-
tarily grounded to a known
good ground.
Does The Voltage Drop?
Check for spark from the coil wire
as the test battery lead is
removed?
Is Adequate Spark Present?
Replace ignition coil and recheck
for spark as set up in steps 11
and 12.
Is Adequate Spark Present?
Ignition coil removed is OK.
Reinstall coil and check coil wire
from distributor cap. If OK,
replace ignition module.
Is Action Complete?
Replace ignition module and
recheck for spark as set up in
steps 11 and 12.
Is Adequate Spark Present?
Replace ignition coil, it too is
faulty.
Is Action Complete?
Is the rotating pole piece still
magnetized?
SERVICE MANUAL NUMBER 23
Value(s) Yes
_
Go to Step 12
–
Go to Step 17
Go to OBD
–
System
Check
–
Go to OBD
System
Check
Go to OBD
–
System
Check
Go to OBD
System
–
Check
Go to Step 18
–
90-861326--1 MARCH 1999
No
Go to Step 23
Go to Step 13
Go to Step 14
–
Go to Step 16
_
Go to Step 24