NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [MZR 2.0, MZR 2.5]

4	HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK
DESCRIPTION	• The starter cranks engine at normal speed but 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 • Improper operation of electronic throttle control system • Inadequate fuel pressure • Purge solenoid valve malfunction • MAF sensor contamination • Incorrect MAF sensor ground voltage • Restriction in exhaust system • EGR valve malfunction • Pressure regulator malfunction (built-in fuel pump unit) • PCM malfunction Warning The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: • 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. (See BEFORE SERVICE PRECAUTION [MZR 2.0, MZR 2.5].) (See AFTER SERVICE PRECAUTION [MZR 2.0, MZR 2.5].) Caution • Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK

DESCRIPTION

• The starter cranks engine at normal speed but 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

• Improper operation of electronic throttle control system

• Inadequate fuel pressure

• Purge solenoid valve malfunction

• MAF sensor contamination

• Incorrect MAF sensor ground voltage

• Restriction in exhaust system

• EGR valve malfunction

• Pressure regulator malfunction (built-in fuel pump unit)

• PCM malfunction

Warning

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system:

• 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. (See BEFORE SERVICE PRECAUTION [MZR 2.0, MZR 2.5].) (See AFTER SERVICE PRECAUTION [MZR 2.0, MZR 2.5].)

Caution

• Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

STEP	INSPECTION	RESULTS	ACTION
1	Inspect 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 • Intake air system restriction (such as air cleaner element, fresh air duct) Are all items normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	Connect the M-MDS to the DLC-2. Switch the ignition to ON (engine off). Retrieve any DTCs. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0, MZR 2.5].) Are any DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [MZR 2.0, MZR 2.5].)
No	Go to the next step.
3	Is the engine overheating?	Yes	Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”. (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 2.0, MZR 2.5].)
No	Go to the next step.
4	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Is there any malfunction?	Yes	Repair or replace the suspected wiring harness.
No	Go to the next step.
5	Inspect the spark plug conditions. (See SPARK PLUG INSPECTION [MZR 2.0, MZR 2.5].) 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 the fuel injector for clogging. Repair or replace the malfunctioning part according to the inspection results.
No	Install the spark plugs on original cylinders, then go to the next step.
6	Visually inspect the CKP sensor and teeth of crankshaft pulley. Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
7	Attempt to start the engine at part throttle. Does the engine run smoothly at part throttle?	Yes	Perform the Electronic Throttle Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0, MZR 2.5].) Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
8	Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZR 2.0, MZR 2.5].) Is the fuel line pressure correct?	Yes	Go to the next step.
No	Zero or low: • Inspect for the following: ― Fuel pump relay, fuel pump circuit ― Fuel line for clogging • If there is a malfunction, repair or replace the malfunctioning part according to the inspection results. • If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].) High: • Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)
9	Is the fuel line pressure held after ignition is off? (See FUEL LINE PRESSURE INSPECTION [MZR 2.0, MZR 2.5].)	Yes	Go to the next step.
No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZR 2.0, MZR 2.5].) • If the fuel injector has a malfunction: ― Replace the fuel injector. (See FUEL INJECTOR REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].) • If the fuel injector is normal: ― Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)
10	Disconnect the vacuum hose from purge solenoid valve and plug opening end of vacuum hose. Start the engine. Is the starting condition improved?	Yes	Inspect if the purge solenoid valve is stuck open. Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
11	Inspect the MAF sensor for following: • Contamination • MAF sensor terminal B voltage (ground circuit) Is there any contamination?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
12	Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
13	Inspect the engine condition while tapping the EGR valve housing. Does the engine condition improve?	Yes	Replace the EGR valve. (See EGR VALVE REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)
No	Go to the next step.
14	Inspect the starting system. (See STARTER INSPECTION [MZR 2.0, MZR 2.5].) Is the starting system normal?	Yes	Inspect for loose connectors or poor terminal contact. • If there is no malfunction: ― Remove the EGR valve and visually inspect for a mechanically stuck EGR valve.
No	Repair or replace the malfunctioning part according to the inspection results.
15	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0, MZR 2.5].) ― If a malfunction remains, inspect the related Service Information and perform repair or diagnosis. • If the vehicle is repaired, troubleshooting is completed. • If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)

STEP

INSPECTION

RESULTS

ACTION

Inspect 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

• Intake air system restriction (such as air cleaner element, fresh air duct)

Are all items normal?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Repeat Step 1.

Connect the M-MDS to the DLC-2.

Switch the ignition to ON (engine off).

Retrieve any DTCs.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.0, MZR 2.5].)

Are any DTCs present?

Yes

Go to the appropriate DTC inspection.

(See DTC TABLE [MZR 2.0, MZR 2.5].)

Go to the next step.

Is the engine overheating?

Yes

Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”.

(See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 2.0, MZR 2.5].)

Go to the next step.

Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders.

Is there any malfunction?

Yes

Repair or replace the suspected wiring harness.

Go to the next step.

Inspect the spark plug conditions.

(See SPARK PLUG INSPECTION [MZR 2.0, MZR 2.5].)

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 the fuel injector for clogging.

Repair or replace the malfunctioning part according to the inspection results.

Install the spark plugs on original cylinders, then go to the next step.

Visually inspect the CKP sensor and teeth of crankshaft pulley.

Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Attempt to start the engine at part throttle.

Does the engine run smoothly at part throttle?

Yes

Perform the Electronic Throttle Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0, MZR 2.5].)

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Inspect the fuel line pressure.

(See FUEL LINE PRESSURE INSPECTION [MZR 2.0, MZR 2.5].)

Is the fuel line pressure correct?

Yes

Go to the next step.

Zero or low:

• Inspect for the following:

― Fuel pump relay, fuel pump circuit

― Fuel line for clogging

• If there is a malfunction, repair or replace the malfunctioning part according to the inspection results.

• If there is no malfunction, replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)

High:

• Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)

Is the fuel line pressure held after ignition is off?

(See FUEL LINE PRESSURE INSPECTION [MZR 2.0, MZR 2.5].)

Yes

Go to the next step.

Inspect the fuel injector.

(See FUEL INJECTOR INSPECTION [MZR 2.0, MZR 2.5].)

• If the fuel injector has a malfunction:

― Replace the fuel injector.

(See FUEL INJECTOR REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)

• If the fuel injector is normal:

― Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)

Disconnect the vacuum hose from purge solenoid valve and plug opening end of vacuum hose.

Start the engine.

Is the starting condition improved?

Yes

Inspect if the purge solenoid valve is stuck open.

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Inspect the MAF sensor for following:

• Contamination

• MAF sensor terminal B voltage (ground circuit)

Is there any contamination?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Visually inspect the exhaust system part.

Is there any deformed exhaust system part?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Inspect the engine condition while tapping the EGR valve housing.

Does the engine condition improve?

Yes

Replace the EGR valve.

(See EGR VALVE REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)

Go to the next step.

Inspect the starting system.

(See STARTER INSPECTION [MZR 2.0, MZR 2.5].)

Is the starting system normal?

Yes

Inspect for loose connectors or poor terminal contact.

• If there is no malfunction:

― Remove the EGR valve and visually inspect for a mechanically stuck EGR valve.

Repair or replace the malfunctioning part according to the inspection results.

• Verify the test results.

― If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0, MZR 2.5].)

― If a malfunction remains, inspect the related Service Information and perform repair or diagnosis.

• If the vehicle is repaired, troubleshooting is completed.

• If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)