SERVICE MANUAL NUMBER 23
FUEL INJECTION SYSTEM TROUBLESHOOTING
Page 5D-23
90-861326--1 MARCH 1999
Cuts Out, Misses Symptom (Continued)
11
1. Check for Electromagnetic Interfer-
ence (EMI). A missing condition can
be caused by EMI on the reference
circuit. EMI can usually be detected
by monitoring engine rpm with a
scan tool or tachometer. A sudden
increase in rpm with little change in
actual engine rpm change, indicates
EMI is present.
2. If EMI is present, locate and repair
the source.
Was a problem found?
-
Go to OBD
System
Check
Go to Step 12
12
1. Review all diagnostic procedures
within this table.
2. If all procedures have been com-
pleted and no malfunctions have
been found, review/inspect the fol-
lowing:
•
Visual/physical inspection.
•
Scan tool data.
•
All electrical connections within a
suspected circuit and/or system.
3. If a problem is found, repair as nec-
essary.
Was a problem found?
-
Go to OBD
System
Check
Contact
MerCruiser
Customer
Service
Rough, Unstable, or Incorrect Idle, Stalling Symptom
Step
Action
Value(s)
Yes
No
Definition: Engine runs unevenly at idle. If severe, the engine or vessel may shake.
Engine idle speed may vary in rpm. Either condition may be severe enough to stall the
engine.
1
Was the “On-Board Diagnostic” (OBD)
System Check performed?
-
Go to Step 2
Go to OBD
System Check
2
Was visual/physical check performed?
-
Go to Step 3
Go to Visual/
Physical
Check
3
1. Check for proper operation of the
IAC valve.
•
Refer to Table A-8 in “General Sys-
tem Diagnostics” section.
2. If a problem is found, repair as nec-
essary.
Was a problem found?
-
Go to OBD
System
Check
Go to Step 4
4
1. Check for proper operation of Igni-
tion Control (IC) circuit and the
Knock Sensor (KS) circuit.
2. If a problem is found, repair as nec-
essary.
Was a problem found?
-
Go to OBD
System
Check
Go to Step 5
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