DIAGNOSTICS
SERVICE MANUAL NUMBER 24
Chart A-7 (1 of 6): Ignition System Check
MEFI 1, MEFI 2 AND MEFI 3 BLACK SCORPION:
IC MODULE
ECM
DISTRIBUTOR
B+
MEFI 1 MEFI 3
MEFI 2
902
RED
A B
COIL
J2-23
J2-8
J1-10
J2-10
J1-24
J1-3
3
PNK
J2-24
J2-6
121
BRN OR GRY
121
WHT
E
NOT USED
J2-11
J2-27
112
DK GRN
31
TAN
D
C
31
TAN
3 PNK
31 BRN
TO IGN
J1-6
9
931 BRN
B
A
121
WHT
CIRCUIT DESCRIPTION MEFI 1, MEFI 2 AND MEFI 3 BLACK SCORPION:
The Distributor Ignition (Dl) system receives supply voltage from the system relay through
CKT 902 to the ignition coil gray connector “B”. Inside the ignition coil, the gray connector
terminal “B” is connected to the black connector terminal “B.” Supply voltage is delivered
from the ignition coil black connector terminal “B” to the distributor Ignition Control (IC) mod-
ule “+” terminal through CKT 3.
Inside the distributor, the pick-up coil and pole piece will produce a voltage signal for cylinder
spark. The voltage signals are processed in the IC module and sent to the ECM. The ECM
will decide if the engine is in the cranking or running mode and adjust timing accordingly.
The voltages or signals are sent between the ECM and the IC module through CKT’s 423,
430,
and 424. CKT 453 is the ground circuit.
The IC module will send the voltage signal to the ignition coil black connector terminal “A”
through CKT 121. The signal will trigger the coil creating secondary spark to be produced.
This secondary spark is sent to the distributor by a high tension lead.
Index
Page 5G-38
90-861327--1 OCTOBER 1999
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 305 CID, Mercury MerCruiser 350 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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