NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [MZI-3.7]
id0103d2801000
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HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK |
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DESCRIPTION
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• Starter cranks engine at normal speed but engine requires excessive cranking time before starting.
• Battery is in normal condition.
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POSSIBLE CAUSE
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• Vacuum leakage
• Poor fuel quality
• Air leakage or restriction in intake-air system
• Low or dead battery
• Charging system malfunction
• PCM DTC is stored.
• Engine overheating
• Purge solenoid valve malfunction
• MAF sensor contamination
• Incorrect MAF sensor ground voltage
• Improper operation of drive-by-wire control system
• Restriction in exhaust system
• Open circuit in PCM ground circuit
• Ignition coil related circuit malfunction
• Erratic signal to ignition coil
• Spark plug malfunction
• Erratic signal from CKP sensor
• Erratic signal from CMP sensor
• Inadequate fuel pressure
• Fuel leakage from fuel system
• PCV valve malfunction
• Starting system malfunction
• Electrical connector loose or terminal poor contact
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Diagnostic procedure
STEP |
INSPECTION |
RESULTS |
ACTION |
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1
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Inspect for the following:
• Vacuum leakage
• Proper fuel quality (such as proper octane, contamination, winter/summer blend)
• Loose bands on intake-air system
• Cracks on intake-air system parts
• Intake-air system restriction (such as air cleaner element, fresh air duct)
Are all items normal?
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Yes
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Go to the next step.
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No
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Repair or replace the malfunctioning part according to the inspection results.
Repeat Step 1.
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2
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Turn the ignition switch to the ON position (Engine off).
Retrieve any PCM DTCs using the M-MDS.
Are there any DTCs displayed?
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Yes
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DTC is displayed:
• Go to the appropriate DTC inspection.
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No
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No DTC is displayed:
• Go to the next step.
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3
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Is the engine overheating?
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Yes
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Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”.
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No
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Go to the next step.
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4
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Disconnect a vacuum hose from purge solenoid valve and plug opening end of vacuum hose.
Start the engine.
Is the starting condition improved?
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Yes
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Inspect if the purge solenoid valve is stuck open.
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 MAF sensor for following:
• Contamination
• MAF sensor terminal B voltage (ground circuit)
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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6
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Attempt to start the engine at part throttle.
Does the engine run smoothly at part throttle?
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Yes
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Inspect the drive-by-wire control system operation.
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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7
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Visually inspect the exhaust system part.
Is there any deformed exhaust system part?
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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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8
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Verify the PCM ground point condition.
Is there any ground point looseness or lifting in the PCM.
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Yes
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Repair the ground point looseness and lifting.
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No
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Go to the next step.
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9
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Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders.
Are wiring harness conditions normal?
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Yes
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Go to the next step.
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No
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Repair or replace suspected wiring harness and connector.
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10
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Perform the spark test.
Is a strong blue spark visible at each cylinder?
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Yes
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Go to the next step.
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No
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Repair or replace the malfunctioning part according to the inspection results.
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11
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Verify the spark plug conditions when the spark plug removed in Step 10.
Is the spark plug wet, covered with carbon or grayish white?
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Yes
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Spark plug is wet or covered with carbon:
• Inspect for fuel leakage from fuel injector.
Spark plug is grayish white:
• Inspect the fuel injector for clogging.
Repair or replace the malfunctioning part according to the inspection results.
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No
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Install the spark plugs on original cylinders.
Go to the next step.
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12
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Inspect the CKP sensor.
Is the CKP sensor normal?
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Yes
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Go to the next step.
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No
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Repair or replace the malfunctioning part according to the inspection results.
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13
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Inspect the CMP sensor.
Is the CMP sensor normal?
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Yes
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Go to the next step.
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No
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Repair or replace the malfunctioning part according to the inspection results.
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14
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Inspect the fuel line pressure.
Is the fuel line pressure correct?
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Yes
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Go to the next step.
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No
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Zero or low:
• Inspect the following:
• If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction)
High:
• Replace the fuel pump unit. (Pressure regulator malfunction)
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15
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Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line.
Is there any fuel leakage?
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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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16
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Inspect the PCV valve with it installed.
Is the PCV valve normal?
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Yes
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Go to the next step.
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No
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Replace the PCV valve.
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17
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Inspect the starting system.
(See STARTER INSPECTION [MZI-3.7].)
Is the starting system normal?
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Yes
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Inspect for loose connectors or poor terminal contact.
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No
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Repair or replace the malfunctioning part according to the inspection results.
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18
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• Verify test results.
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