Distributor

49tucci

New Member
Jun 30, 2019
4
Boat Info
1997 33 searay amberjack
Engines
7.4 mercruiser
distributors on 7.4 MerCruiser engines 1997 seems to be an issue
Replace distributors on both engines
 
I have replaced two distributors with on two different engines within two months is any one having any problems with them.
 
Engine won’t start distributor not letting gas to flow to ejectors. Baffled mechanics
 
I think you got the explanation wrong, that's not how it works. But, whatever other info you have, post it
 
My explanation is correct, electronically the distributor is not allowing gas to flow to ejectors . Mechanic said he has replaced four this season.
 
you may need to replace the IC module, not the dist. TH module supplies the pulse to the ecm to send fuel to the injectors and operate them
 
DISTRIBUTOR REFERENCE (DIST REF)
GM refers to this as Ignition Control (IC). The distributor reference (engine speed signal)
is supplied to the ECM by way of the “Dist Ref Hi” line from the High Energy Ignition (HEI).
This pulse counter type input creates the timing signal for the pulsing of the fuel injectors,
as well as the Ignition Control (IC) functions. This signal is used for a number of control and
testing functions within the ECM.
 
MULTI-PORT FUEL INJECTION DESCRIPTIONS AND SYSTEM OPERATION SERVICE MANUAL NUMBER 23
Page 5B-26 90-861326--1 MARCH 1999
The ECM controls the primary current going to the ignition coil. It sends a voltage signal to
the IC module that sends a voltage signal to the ignition coil. This signal will trigger the coil
creating secondary spark to be produced. The secondary spark is sent to the distributor and
then to the correct cylinder by high tension leads.
The Ignition Control (IC) module maintains the base ignition timing. It also has a 27-degree
spark advance built into it in case there is a Code for an IC operation failure detected while
the engine is running. The engine will continue to run but at reduced performance.
J1-10
J2-10
J1-24
76082
ECM
A B
J1-20
J1-4
J1-5
450 BLK
B A
B A
J1-3
902
RED
423 WHT
121 WHT
424 TAN/BLK
430 PUR/WHT
453 RED/BLK
BRN
PNK
450 BLK
450 BLK
BLK = BLACK
BLU = BLUE
BRN = BROWN
GRY = GRAY
GRN = GREEN
ORN = ORANGE
PNK = PINK
PUR = PURPLE
RED = RED
TAN = TAN
WHT = WHITE
YEL = YELLOW
LIT = LIGHT
DRK = DARK
a
b
c
d
e
f
g
h
i
k j
l
m
n
o
Typical System Shown
a - ECM Ground
b - ECM Ground
c - ECM Ground
d - Ignition Control
e - Distributor Reference HIGH
f - Bypass
g - Distributor Reference LOW
h - To Tachometer
i - 2-Way Black Connector
j - 2-Way Gray Connector
k - From Ignition Relay
l - 2-Way Coil Jumper Harness
m - IC Module
n - 8 Cylinder Distributor
o - Pick-up Coi
 

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