NO.6 SLOW RETURN TO IDLE/FAST IDLE [WL-3]
id0103b5912600
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6
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Slow return to idle/fast idle
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DESCRIPTION
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• The engine takes more time than normal to return to idle speed.
• The engine speed continues at fast idle after warm-up
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POSSIBLE CAUSE
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• Malfunction of ECT sensor
• Thermostat is stuck open.
• Air leakage from intake-air system
• Fuel injection timing is incorrect.
• Incorrect adjustment of accelerator cable free play
• Incorrect adjustment of idle speed
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Diagnostic procedure
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STEP |
INSPECTION |
ACTION |
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1
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• Connect the M-MDS to the DLC.
• Turn the engine switch to the ON position (Engine off).
• Retrieve any DTCs.
• Is a DTC displayed?
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No
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No DTC is displayed:
• Go to the next step.
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Yes
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DTC is displayed:
• Go to the appropriate DTC test.
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2
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• Inspect the injection timing.
• Is the injection timing normal?
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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 TCV.
If the TCV is normal, adjust the injection timing.
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3
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• Inspect for air leakage from the intake-air system components while racing the engine to a higher speed.
• Is there any air leakage?
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Yes
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Repair or replace if necessary.
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No
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Go to the next step.
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4
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• Remove thermostat and inspect the operation.
• Is the thermostat normal?
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Yes
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Inspect and adjust the idle speed.
(See ENGINE TUNE-UP [WL-3].)
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No
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Replace the thermostat.
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5
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• Verify the test results. If normal, return to the diagnostic index to service any additional symptoms.
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