4
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HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK
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DESCRIPTION |
• The starter cranks the engine at normal speed but the engine requires excessive cranking time before starting.
• The battery is in normal condition.
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POSSIBLE CAUSE |
• Erratic signal to ignition coil
• 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
• Pressure regulator malfunction
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:
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Diagnostic procedure
STEP
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INSPECTION
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RESULTS
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ACTION
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1
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Inspect the following:
• Vacuum leakage
• Proper fuel quality (e.g. proper octane, contamination, winter/summer blend)
• Loose bands on the intake-air system
• Cracks on the intake-air system parts
• Air cleaner restriction
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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Service if necessary.
Repeat Step 1.
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2
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Connect the WDS or equivalent to the DLC-2.
Retrieve any KOEO and KOER DTC.
(See KOEO/KOER SELF-TEST.)
Are any KOEO or KOER DTCs displayed?
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Yes
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DTC is displayed:
Go to the applicable DTC test.
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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 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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Inspect the ignition coil related harnesses condition (intermittent open or short) for all cylinders.
Are 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 the suspected wiring harnesses.
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5
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Inspect the spark plugs.
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 the fuel injector.
Spark plug is grayish white:
Inspect for clogged fuel injector.
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No
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Install spark plugs on original cylinders.
Go to the next step.
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6
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Visually inspect the CKP sensor and teeth of the crankshaft pulley.
Are the CKP sensor and teeth of the crankshaft pulley 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 malfunctioning parts.
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7
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Measure the gap between the CKP sensor and teeth of the crankshaft pulley.
Specification 0.5-1.5 mm {0.02-0.05 in}
Is the gap within specification?
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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 plate.
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8
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Remove and shake the PCV valve.
Does the PCV valve rattle?
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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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9
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Install a fuel pressure gauge between the fuel pipe and fuel distributor.
Connect on the WDS or equivalent to the DLC-2.
Turn on fuel pump using the FP PID in the output state control of the datalogger function.
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 fuel pump relay and the fuel pump unit related circuits.
Inspect for fuel leakage inside the pressure regulator.
Inspect for a clogged main fuel line.
High:
Inspect the pressure regulator for the cause of high pressure.
Inspect for a clogged fuel return line.
Inspect the vacuum hose to the pressure regulator.
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10
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Is the fuel line pressure held after FP PID is turned off?
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Yes
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Go to the next step.
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No
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Inspect the pressure regulator diaphragm.
• If the condition is normal, inspect the fuel injector.
• If the condition is not normal, replace the pressure regulator.
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11
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Disconnect the vacuum hose from the pressure regulator and the plug hose.
Start the engine.
Does the fuel line pressure remain within ±20 kPa {±0.21 kgf/cm2, ±3 psi} while driving the vehicle?
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Yes
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Go to the next step.
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No
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Inspect for a clogged fuel filter.
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12
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Connect the vacuum hose to the pressure regulator.
Install a vacuum gauge to the intake manifold.
Start the engine.
Does the fuel pressure gauge reading increase as the vacuum gauge reading decreases and/or the fuel pressure gauge reading decrease as the vacuum gauge reading increase?
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Yes
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Go to the next step.
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No
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Connect a vacuum pump to the pressure regulator.
Start that the engine.
Verify fuel pressure gauge reading changes as the vacuum changes.
• If it changes, inspect the vacuum line.
• If it does not change, replace the pressure regulator.
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13
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Disconnect the vacuum hose from the purge solenoid valve and plug the open end of the vacuum hose.
Attempt to start the engine.
Is the starting condition improved?
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Yes
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Inspect if the purge solenoid valve sticks open.
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No
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Go to the next step.
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14
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Inspect the MAF sensor for contamination.
Is there any contamination?
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Yes
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Replace the MAF sensor.
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No
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Go to the next step.
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15
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Is there restriction in the exhaust system?
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Yes
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Inspect the exhaust system.
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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 starting system.
(See STARTER INSPECTION [ZJ, ZY].)
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 components as required.
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17
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Verify test results.
• If normal, return to the diagnostic index to service any additional symptoms.
• If malfunction remains, replace or reprogram the PCM.
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