Downloaded from www.Manualslib.com manuals search engine Hard Start / Long Crank / Erratic Start / Erratic Crank
The following conditions apply to this symptom:
•The engine cranks for an extended period of time.
• The engine starts hard during a long cranking time.
1.PRELIMINARY CHECKS
• Confirm that the correct starting procedure was used by the customer before proceeding with diagnosis.
• Carry out the following preliminary checks:
Vacuum leaks
Fuel quality (concerns such as correct octane, contamination, winter/summer blend)
Intake air system (tubes)
Air cleaner (restrictions)
Battery condition and starter current draw.
Are all checks OK?
Ye s>>Go to the next step.
No
>>Repair as necessary.
Verify the symptom no longer exists.
2.CHECK ECM DTC
• With scan tool X-431, select view DTC and data stream in ECM.
Are there any DTCs present?
Ye s>>See the Diagnostic Trouble Code (DTC) List.
Go to the specific diagnostic test to troubleshoot the DTC.
No
>>Go to the next step.
3.CHECK SECONDARY IGNITION SYSTEM
• Perform the following to test the secondary ignition system:
Disconnect the injector fuse.
Remove any of the 4 spark plugs.
Connect the spark plug to spark plug wire.
Ground the spark plug on the cylinder block.
Crank the engine to test the secondary ignition system with the spark plugs removed.
Is a strong blue spark visible at each spark plug while cranking the engine?
Ye s>>Go to the next step.
No
>>Check Camshaft Position (CMP) sensor signal at ECM.
If CMP sensor is OK, check the following:
Crankshaft Position (CKP) sensor malfunction
Faulty spark plug wires
Faulty spark plugs
ELECTRONIC ENGINE CONTROLS - 2.4L ENGINE SYMPTOM DIAGNOSIS
03
03–549Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine Back Fires
The following conditions apply to this symptom:
•The engine will back fire when operated.
• The engine back fire occurs at all operating parameters.
1.PRELIMINARY CHECKS
• Carry out the following preliminary checks:
Vacuum lines (check for damage and correct routing).
Spark plug wire routing (correct firing order).
Are all checks OK?
Ye s>>Go to the next step.
No
>>Repair as necessary.
Verify the symptom no longer exists.
2.CHECK ECM DTC
• Turn the ignition switch on.
• With the scan tool X-431, select view DTC and stream data in ECM.
Are there any DTCs present?
Ye s>>See the Diagnostic Trouble Code (DTC) List.
Go to the specific diagnostic test to troubleshoot the DTC.
No
>>Go to the next step.
3.CHECK SECONDARY IGNITION SYSTEM
• Perform the following to test the secondary ignition system:
Disconnect the injector fuse.
Remove any of the 4 spark plugs.
Connect the spark plug to spark plug wire.
Ground the spark plug on the cylinder block.
Crank the engine to test the secondary ignition system with the spark plugs removed.
Is a strong blue spark visible at each spark plug while cranking the engine?
Ye s>>Go to the next step.
No
>>Check Camshaft Position (CMP) sensor signal at ECM.
If CMP sensor is OK, check the following:
Crankshaft Position (CKP) sensor malfunction
Spark plug wires
Spark plugs
4.CHECK FUEL QUALITY
• Check fuel quality (concerns such as correct octane, contamination).
Is the fuel quality OK?
Ye s>>Go to the next step.
No
>>Repair as necessary.
Verify the symptom no longer exists.
ELECTRONIC ENGINE CONTROLS - 2.4L ENGINE SYMPTOM DIAGNOSIS
03–556Chery Automobile Co., Ltd.
