No.4 Hard To Start/Long Crank - Mazda 6 2002 Workshop Manual

NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK
4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK
• Starter cranks engine at normal speed but engine requires ecessive cranking time before starting.
DESCRIPTION
• Battery is in normal condition.
• 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 miture ratio control
• Air cleaner restriction
• IAC valve malfunction
• PCV valve malfunction
• Inadequate fuel pressure
• Purge solenoid valve malfunction
• MAF sensor contamination
• Restriction in ehaust system
• EGR valve malfunction
• Pressure regulator malfunction
POSSIBLE CAUSE
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
• • • • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or
Caution
• • • • Disconnecting/connecting quick release connector without cleaning it may possibly cause
Diagnostic procedure
STEP INSPECTION
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?
2 Connect WDS or equivalent to DLC-2.
Retrieve any KOEO and KOER DTC.
Is any KOEO or KOER DTC displayed?
3 Is engine overheating?
4 Inspect for cracks on high-tension leads.
Are there any cracks on high-tension leads?
5 Inspect spark plug conditions.
Is spark plug wet, covered with carbon or
grayish white?
TROUBLESHOOTING
keep sparks and flames away from fuel.
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
(See F–17 AFTER REPAIR
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.
PROCEDURE.)
PROCEDURE.)
RESULTS
Yes Go to net step.
No Service as necessary.
Repeat Step 1.
Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Go to net step.
Yes Go to symptom troubleshooting “No.17 Cooling system
concerns – Overheating”.
No Go to net step.
Yes Repair suspected high-tension leads.
No Go to net step.
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 net step.
A6E398018881W06
ACTION
F–189
F