SERVICE MANUAL NUMBER 23
FUEL INJECTION SYSTEM TROUBLESHOOTING
Hesitation, Sag, Stumble Symptom
Step
Action
Value(s)
Yes
No
Definition: Momentary lack of response as the throttle lever is advanced. Can occur at
all engine speeds. Usually most severe when first starting out. May cause engine to stall
if severe enough.
Was the “On-Board Diagnostic” (OBD)
System Check performed?
Go to OBD
1
-
-
Go to Step 2 System Check
Was visual/physical check performed?
Go to Visual/
Physical
Check
2
Go to Step 3
1.
2.
Check for contaminated fuel.
Check water separating fuel filter.
3
4
3. If a problem is found, repair as nec-
essary.
Was a problem found?
Go to OBD
System
Check
-
-
Go to Step 4
1.
Check or proper fuel pressure while
the condition exists.
•
Refer to Table A-4 in “General Sys-
tem Diagnostics” section.
2.
If a problem is found, repair as nec-
essary.
Go to OBD
System
Check
Was a problem found?
Go to Step 5
1.
Check fuel injectors.
•
Refer to Injector Balance Test in
“Test General System Diagnostics”
section.
5
6
2.
If a problem is found, repair as nec-
essary.
Go to OBD
System
Check
Was a problem found?
-
-
Go to Step 6
Go to Step 7
1.
Check for proper operation of Igni-
tion Control (IC) circuit and the
Knock Sensor (KS) circuit.
If a problem is found, repair as nec-
essary.
2.
Go to OBD
System
Check
Was a problem found?
1.
Check integrity of the primary and
secondary wiring.
2.
3.
Check routing of the wiring.
Check condition of IC module,
pick-up coil, distributor cap, rotor
and spark plug wires.
7
4.
If a problem is found, repair as nec-
essary.
Go to OBD
System
Check
Was a problem found?
-
Go to Step 8
Index
90-861326--1 MARCH 1999
Page 5D-19
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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