NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZI-3.7]
id0103d2812100
13 |
KNOCKING/PINGING - ACCELERATION/CRUISE |
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DESCRIPTION
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Sound is heard 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
• CHT sensor malfunction
• IAT sensor malfunction
• MAF sensor malfunction
• Knock sensor malfunction
• Erratic signal from CMP sensor
• Inadequate engine compression
• Inadequate fuel pressure
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Diagnostic procedure
STEP |
INSPECTION |
RESULTS |
ACTION |
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1
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Connect the M-MDS to the DLC-2.
Access ECT PID.
Verify ECT PID is less than 116°C {241°F} during driving.
Is ECT PID less than specification?
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Yes
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Go to the next step.
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No
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Inspect the cooling system for cause of overheating.
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2
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Connect the M-MDS to the DLC-2.
Access IAT and MAF PIDs.
Monitor each PID.
(See PCM INSPECTION [MZI-3.7].)
Are PIDs normal?
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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:
Inspect IAT sensor
MAF PID:
Inspect MAF sensor
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3
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Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON position (engine off).
Are there any DTCs displayed?
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Yes
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DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [MZI-3.7].)
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No
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No DTC is displayed:
Go to the next step.
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4
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Is engine compression correct?
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Yes
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Go to the next step.
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No
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Inspect for cause.
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5
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Install fuel pressure gauge between fuel pipe and fuel distributor.
Start the engine and idle it.
Measure fuel line pressure during idle.
Is fuel line pressure correct during idle?
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Yes
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Inspect the ignition timing.
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No
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Low:
Inspect the fuel pump relay and fuel pump circuit.
Inspect the fuel line for clogging.
If there is no malfunction, replace the fuel pump unit.
High:
Replace the fuel pump unit.
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6
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Inspect the knock sensor.
Is the knock sensor normal?
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Yes
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Inspect ignition timing.
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No
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Replace the knock sensor.
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7
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• Verify test results.
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