NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [ZJ, Z6]

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NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [ZJ, Z6]

B3E010318881W37

4 | 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.

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
• Incorrect MAF sensor GND voltage
• 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 the "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual.
  (See BEFORE SERVICE PRECAUTION [ZJ, Z6, LF].)
  (See AFTER SERVICE PRECAUTION [ZJ, Z6, LF].)

  Caution

  • If there is foreign material on the connecting area of the quick release connector, it might damage the connector or fuel pipe. To prevent this, disconnect the connector and clean the connecting area before connecting.

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
--- | --- | --- | ---

1

Inspect for the following:
• Vacuum leakage
• Proper fuel quality (such as proper octane, contamination, winter/summer blend)
• Loose bands on intake-air system
• Cracks on 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 WDS or equivalent to the DLC-2. Retrieve any KOEO and KOER DTCs using WDS or equivalent. Is any KOEO or KOER DTC displayed? | Yes | DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [ZJ, Z6].)
No | No DTC is displayed: Go to the next step.
3 | Is the engine overheating? | Yes | Go to symptom troubleshooting "No.17 Cooling system concerns - Overheating".
No | Go to the next step.
4 | Inspect the ignition coil related wiring harnesses condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal? | Yes | Go to the next step.
No | Repair the wiring harnesses.
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 the fuel injector. Spark plug is grayish white: Inspect for clogged the fuel injector.
No | Install spark plugs on original cylinders. Go to the next step.
6 | Visually inspect the CKP sensor and teeth of the crankshaft pulley. Are the CKP sensor and teeth of the crankshaft pulley normal? | Yes | Go to the next step.
No | Replace the malfunctioning part.
7 | Measure 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? | Yes | Go to the next step.
No | Replace the crankshaft pulley.
8 | Remove and shake the PCV valve. Does the PCV valve rattle? | Yes | Go to the next step.
No | Replace the PCV valve.
9 | Install fuel pressure gauge between the fuel pipe and the fuel distributor. Connect WDS or equivalent to DLC-2. Turn ON fuel pump using FP PID in output state control of datalogger function. Is fuel line pressure correct? (See FUEL LINE PRESSURE INSPECTION [ZJ, Z6, LF].) | Yes | Go to the next step.

No

Zero or low:

Inspect the fuel pump relay and the fuel pump unit related circuits.
Inspect the fuel line for clogging.
• If normal, replace the fuel pump unit.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [ZJ, Z6, LF].)

High:

Replace the fuel pump unit.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [ZJ, Z6, LF].)

10 | Is fuel line pressure held after FP PID is turned OFF? (See FUEL LINE PRESSURE INSPECTION [ZJ, Z6, LF].) | Yes | Go to the next step.
No | Inspect the pressure regulator diaphragm condition. • If condition is normal, inspect the fuel injector. • If condition is not normal, replace the pressure regulator.
11 | Disconnect a vacuum hose from the purge solenoid valve and plug opening end of the vacuum hose. Start the engine. Is starting condition improved? | Yes | Inspect if the purge solenoid valve is stuck open.
No | Go to the next step.
12 | Inspect the MAF sensor for the following: • Contamination • MAF sensor terminal B voltage (GND circuit) Is there any contamination? | Yes | Replace the MAF sensor.
No | Go to the next step.
13 | Visually inspect the exhaust system part. Is there any deformed exhaust system part? | Yes | Replace the part.
No | Go to the next step.
14 | Inspect engine condition while tapping the EGR valve housing. Does the engine condition improve? | Yes | Replace EGR valve.
No | Go to the next step.
15 | Inspect the starting system. (See STARTER INSPECTION.) 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 as required.

16

Verify test results.
• If normal, return to diagnostic index to service any additional symptoms.
(See ENGINE SYMPTOM TROUBLESHOOTING [ZJ, Z6].)
• If malfunction remains, inspect related Service information perform repair or diagnosis.

  - If vehicle repaired, troubleshooting completed.
  - If vehicle not repaired or additional diagnostic information not available, replace the PCM.
  (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [ZJ, Z6].)