NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZR 1.8, MZR 2.0, MZR 2.5]
id0103d4812100
13 |
KNOCKING/PINGING—ACCELERATION/CRUISE |
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DESCRIPTION
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• Sound is produced when air/fuel mixture is ignited by something other than spark plug (such as hot spot in combustion chamber).
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POSSIBLE CAUSE
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• Engine overheating due to cooling system malfunction
• ECT sensor malfunction
• Erratic signal to PCM
• PCM DTC is stored
• Low engine compression
• Excessive or insufficient fuel pressure
• KS malfunction
• Improper ignition timing
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Diagnostic procedure
STEP |
INSPECTION |
RESULTS |
ACTION |
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1
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Access the ECT PID using the M-MDS.
Verify the ECT PID value is less than 116 °C {241 °F} during driving.
Is the ECT PID value less than the specification?
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Yes
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Go to the next step.
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No
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Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”.
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2
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Access the IAT and MAF PIDs using the M-MDS.
Do the PIDs indicate the correct values under the trouble condition?
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Yes
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Go to the next step.
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No
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IAT PID is not specified:
• Inspect the IAT sensor.
MAF PID is not specified:
• Inspect the MAF sensor.
Repair or replace the malfunctioning part according to the inspection results.
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3
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Perform the PCM DTC inspection using the M-MDS.
Are any DTCs present?
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Yes
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Go to the applicable DTC inspection.
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No
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Go to the next step.
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4
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Inspect the engine compression.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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5
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Inspect the fuel line pressure.
Is there any malfunction?
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Yes
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Zero or low:
• Inspect the fuel pump relay and the fuel pump circuit.
(See RELAY INSPECTION.)
• Inspect the fuel line for clogging.
High:
• Replace the fuel pump unit.
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No
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Go to the next step.
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6
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Inspect the KS.
Is there any malfunction?
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Yes
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Replace the KS.
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No
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Inspect the ignition timing.
Repair or replace the malfunctioning part according to the inspection results.
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7
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Verify test results.
• If normal, return to the diagnostic index to service any additional symptoms.
• If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis.
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