DIAGNOSTICS
SERVICE MANUAL NUMBER 24
Chart A-6 (1 of 2): EFI System/Ignition Relay Check
IGNITION
50A
CIRCUIT
BREAKER
86
85
87
90
AMP
FUSE
30
902 RED
TO ECM
TO FUEL
PUMP
RELAY
TO IGN
COIL
INJ/ECM/KS
MODULE
CIRCUIT DESCRIPTION:
Battery voltage is constantly supplied to terminal “30” of the system relay. When the ignition
switch is moved to the “RUN” position, battery voltage is supplied to terminal “86” of the sys-
tem relay. The pull-in coil is then energized creating a magnetic field which closes the con-
tacts of the system relay. Voltage and current are then supplied to the ignition control mod-
ule, injectors, ECM, and fuel pump relay through terminal “87” CKT 902 of the system relay.
DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation or a
wire broken inside the insulation. Check for the following items:
•
•
Poor connection or damaged harness. Inspect the ECM harness and connectors for
improper mating,broken locks, improperly formed or damaged terminals, poor termi-
nal to wire connection, and damaged harness.
Contaminated or dirty fuel may cause the fuel pump to seize, which will cause the
fuel pump relay fuse to fail.
Index
Page 5G-36
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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