MerCruiser 305 CID (5.0L), Руководство по обслуживанию

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FUEL INJECTION SYSTEM TROUBLESHOOTING
SERVICE MANUAL NUMBER 24
90-861327--1 OCTOBER 1999 Page 5F-11
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.
1
Was the “On-Board Diagnostic” (OBD)
System Check performed?
Step 2 OBD
2 Was visual/physical check performed?
Step 3
Visual/ Physical
Check
3
1. Check base timing.
•
Refer to Ignition Timing Set Procedure in
the Distributor Ignition section.
Was a problem found?
Step 4
4
1. Check for proper operation of Ignition Con-
trol (IC) circuit and the Knock Sensor (KS)
circuit.
Was a problem found?
Step 5
5
1. Check for good ignition system ground.
2. Check spark plugs for proper gap and heat
range.
Was a problem found? Step 6
6
1. Check for contaminated fuel.
2. Check for poor fuel quality and proper
octane rating.
Was a problem found? Step 7
7
1. Check for proper fuel pressure.
•
Refer to Table A-4 in “General System
Diagnostics” section.
Was fuel pressure 30 psi for EFI or 3–7 psi
for carbureted engines?
OBD
Step 8
8 Is a scan tool being used? Step 9 Step 10
9
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.
Is detonation present?
Step 10 OBD
10
1. Check for obvious overheating problems:
•
Loose water pump belt.
•
Faulty or incorrect water pump.
•
Restriction in cooling system.
•
Faulty or incorrect thermostat.
Was a problem found?
OBD Step 11
Index