SERVICE MANUAL NUMBER 24
FUEL INJECTION SYSTEM TROUBLESHOOTING
Detonation / Spark Knock Symptom
Step
Action
Yes
No
PROCEED TO
Definition: A mild to severe ping, usually worse under acceleration. The engine
makes sharp metallic knocks that change with throttle opening.
Was the “On-Board Diagnostic” (OBD)
System Check performed?
1
Step 2
Step 3
OBD
Visual/ Physical
Check
2
3
Was visual/physical check performed?
1.
Check base timing.
•
Refer to Ignition Timing Set Procedure in
the Distributor Ignition section.
Was a problem found?
Step 4
Step 5
1.
Check for proper operation of Ignition Con-
trol (IC) circuit and the Knock Sensor (KS)
circuit.
4
5
6
Was a problem found?
1.
2.
Check for good ignition system ground.
Check spark plugs for proper gap and heat
range.
Was a problem found?
Step 6
Step 7
1.
2.
Check for contaminated fuel.
Check for poor fuel quality and proper
octane rating.
Was a problem found?
1.
•
Check for proper fuel pressure.
Refer to Table A-4 in “General System
Diagnostics” section.
7
8
Was fuel pressure 30 psi for EFI or 3–7 psi
for carbureted engines?
OBD
Step 8
Is a scan tool being used?
Step 9
Step 10
1.
If scan tool readings are normal (Refer to
“Scan Tool Normal Specifications” in this
section) and there are no engine mechani-
cal faults, fill fuel tank with a known high
quality gasoline.
9
Is detonation present?
Step 10
OBD
1.
•
Check for obvious overheating problems:
Loose water pump belt.
•
•
•
Faulty or incorrect water pump.
Restriction in cooling system.
Faulty or incorrect thermostat.
10
Was a problem found?
OBD
Step 11
Index
90-861327--1
OCTOBER 1999
Page 5F-11
| 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 |
(1 votes, average: 4 out of 4)
Marine readers have rated Mercury MerCruiser Engines Service Manual Number 24 GM V-8 305 CID 350 CID 4.0 out of 4.0 based on 1 product reviews. Great performance engine.
Class 1