NO.4 HARD START/LONG CRANK/ERRATIC START/ERRATIC CRANK[AJ (3.0L Duratec)]


id0103a7804600

4
Hard start/long crank/erratic start/erratic crank
DESCRIPTION
•  The starter cranks engine at normal speed but the engine requires excessive cranking time before starting.
•  The 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
•  Air cleaner restriction
•  IAC solenoid valve malfunction
•  PCV valve malfunction
•  Inadequate fuel pressure
•  Purge solenoid valve malfunction
•  MAF sensor contamination
•  Restriction in exhaust system
•  EGR valve 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 SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual.

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
•  Inspect for the following:
―  Vacuum leakage
―  Proper fuel quality (e.g. proper octane, contamination, winter/summer blend)
―  Loose bands on intake-air system
―  Cracks on the intake-air system parts
―  Air cleaner restriction
•  Are all items normal?
Yes
Go to the next step.
No
Service if necessary.
Repeat Step 1.
2
•  Connect the M-MDS to the DLC–2.
•  Turn the ignition to the ON position (Engine off).
•  Retrieve any DTCs.
•  Is “PASSED” displayed?
Yes
No DTC is displayed:
•  Go to the next step.
No
DTC is displayed:
•  Go to the appropriate DTC test.
3
•  Is the engine overheating?
Yes
Go to flowchart “No.17 Cooling system concerns—Overheating”.
No
Go to the next step.
4
•  Inspect for cracks on the high-tension leads
•  Is there any crack on the high-tension leads?
Yes
Repair suspected high-tension lead.
No
Go to the next step.
5
•  Inspect the spark plug conditions.
•  Is the 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 the next step.
6
•  Visually inspect CKP sensor and teeth of crankshaft pulley.
•  Are CKP sensor and teeth of crankshaft pulley normal?
Yes
Go to the next step.
No
Replace malfunctioning part.
7
•  Remove and shake PCV valve.
•  Does PCV valve rattle?
Yes
Go to the next step.
No
Replace the PCV valve.
8
•  Install fuel pressure gauge to fuel line.
•  Connect the M-MDS to DLC-2.
•  Turn the fuel pump on using FP PID in output state control of datalogger function.
•  Is the fuel line pressure connect?
Yes
Go to the next step.
No
Zero or low:
Inspect the fuel pump, fuel pump stop switch and fuel pump relay related circuit.
Inspect for clogged fuel line.
•  If normal, replace the fuel pump unit.
High:
Replace the fuel pump unit.
9
•  Is the fuel line pressure held after FP PID is turned to OFF?
Yes
Go to the next step.
No
Inspect the fuel injector.
•  If the fuel injector is normal, replace the fuel pump unit.
10
•  Disconnect the vacuum hose from purge solenoid valve and plug opening end of vacuum hose.
•  Attempt to start engine.
•  Is the starting condition improved?
Yes
Inspect if the purge solenoid valve sticks open.
No
Go to the next step.
11
•  Inspect the MAF sensor for contamination.
•  Is there any contamination?
Yes
Replace the MAF sensor.
No
Go to the next step.
12
•  Visually inspect the exhaust system part.
•  Is there any deformed exhaust system part?
Yes
Replace the suspected part.
No
Go to the next step.
13
•  Inspect engine condition while tapping EGR valve housing.
•  Does the engine condition improve?
Yes
Replace the EGR valve.
No
Go to the next step.
14
•  Inspect the starting system.
•  Is the starting system normal?
Yes
Inspect for loose connectors or poor terminal contact.
•  If normal, remove the EGR valve and visually inspect for mechanically stuck EGR valve.
No
Repair or replace the components if necessary.
15
•  Verify the test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If malfunction remains, inspect related Service Information and perform repair or diagnosis.
•  If vehicle is repaired, troubleshooting completed.
•  If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.