Mazda 6 2002 - No.4 Hard to Start;Long Crank

TROUBLESHOOTING
F189
F
NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK
A6E398018881W06
Diagnostic procedure
4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK
DESCRIPTION
• Starter cranks engine at normal speed but engine requires excessive cranking time before starting.
• Battery is in normal condition.
POSSIBLE CAUSE
• Spark leakage from high-tension leads
• Vacuum leakage
• Poor fuel quality
• Starting system malfunction
• Spark plug malfunction
• Air leakage from intake-air system
• Erratic signal from CKP sensor
• Erratic signal from CMP sensor
• Improper air/fuel mixture ratio control
• Air cleaner restriction
• IAC valve malfunction
• PCV valve malfunction
• Inadequate fuel pressure
• Purge solenoid valve malfunction
• MAF sensor contamination
• Restriction in exhaust system
• EGR valve malfunction
• Pressure regulator malfunction
Warning
The following troubleshooting flow chart contains the fuel system diagnosis and repair
procedures. Read the following warnings before performing the fuel system services:
•
••
• Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always
keep sparks and flames away from fuel.
•
••
• Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or
death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete
"BEFORE REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this
manual.
(See F17 BEFORE REPAIR PROCEDURE.)
(See F17 AFTER REPAIR PROCEDURE.)
Caution
•
••
• Disconnecting/connecting quick release connector without cleaning it may possibly cause
damage to fuel pipe and quick release connector. Always clean quick release connector
joint area before disconnecting/connecting, and make sure that it is free of foreign material.
STEP INSPECTION RESULTS ACTION
1 Inspect for following:
• Vacuum leakage
• Proper fuel quality (e.g. proper octane,
contamination, winter/summer blend)
• Loose bands on intake-air system
• Cracks on intake-air system parts
• Air cleaner restriction
Are all items okay?
Yes Go to next step.
No Service as necessary.
Repeat Step 1.
2 Connect WDS or equivalent to DLC-2.
Retrieve any KOEO and KOER DTC.
Is any KOEO or KOER DTC displayed?
Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Go to next step.
3 Is engine overheating? Yes Go to symptom troubleshooting No.17 Cooling system
concerns  Overheating.
No Go to next step.
4 Inspect for cracks on high-tension leads.
Are there any cracks on high-tension leads?
Yes Repair suspected high-tension leads.
No Go to next step.
5 Inspect spark plug conditions.
Is spark plug wet, covered with carbon or
grayish white?
Yes Spark plug is wet or covered with carbon:
Inspect for fuel leakage from fuel injector.
Spark plug is grayish white:
Inspect for clogged fuel injector.
No Install spark plugs on original cylinders.
Go to next step.