Mercury 75 Service Manual page 68

CDM Trouble Shooting Flowchart
Chart #3 (At least one CDM has spark)
Step Action
1 Resistance Check ALL CDMs
2 Test all CDMs at Cranking with
Spark Gap Tester
Spark on All CDMs
Will spark jump a 7/16 in.
(11.11 mm) gap?
3 Check Trigger Output:
Cranking with CDM disconnected.
Cranking with CDM connected.
4 V6 Models
Resistance Check Crank Position
Sensor
5 Test all CDMs at Cranking with
Spark Gap Tester
Spark on All CDMs?
Will spark jump a 7/16 in.
(11.11 mm) gap?
6 If mis-firing is in a repeatable
range:
Perform DVA readings on stator
and trigger at all running speeds.*
* Note: Stator tests will only isolate problem down to
a charging pair. Further testing is necessary to deter-
mine faulty CDM. Disconnecting one CDM of the
charging pair is recommended.
2A-30 - ELECTRICAL
Value Yes
Refer to chart Step 3
7/16 in. Run Engine
(11.11 mm) Verify Repair
gap
Step 6
1 Volt and Step 5
above - CDM
disconnected.
0.2 - 5 Volts -
CDM
connected.
900 - 1300 Step 5
Ohms
7/16 in. Run Engine
(11.11 mm) Verify Repair
gap
Step 6
Stator: Run Engine
200 Volts and Verify Repair
above
END
Trigger:
2 Volts and
above
No Tools
Replace any DVA/Multimeter
CDMs that P/N 91-99750
do not pass
specifica-
tions even if
they fire
Step 2
Step 3 Spark Gap Tes-
ter
P/N 91-850439
2, 3, & 4 Cyl DVA/Multimeter
- Replace P/N 91-99750
Trigger
TPI/CDM Test
Run Engine Harness
Verify Repair 84-825207A2
Step 6
6 Cyl–Step 4
Replace DVA/Multimeter
Crank Posi- P/N 91-99750
tion Sensor
Run Engine
Verify Repair
Step 6
Replace any Spark Gap Tes-
non-firing ter
CDMs P/N 91-850439
Step 6
Refer to DVA/Multimeter
*Note Below. P/N 91-99750
TPI/CDM Test
Harness
84-825207A2
90-830234R3 DECEMBER 1997