NO.19 EXHAUST SMOKE [MZI-3.7]

19	EXHAUST SMOKE
DESCRIPTION	• Blue, black, or white smoke from exhaust system.
POSSIBLE CAUSE	Blue smoke (Burning oil): • PCV valve malfunction • Engine internal oil leakage White smoke (Water in combustion): • Cooling system malfunction (coolant loss) • Engine internal coolant leakage Black smoke (Rich fuel mixture): • Air cleaner restriction • Intake-air system is collapsed or restricted. • PCM DTC is stored. • Erratic signal to PCM ― APP sensor or related circuit malfunction ― CHT sensor or related circuit malfunction ― IAT sensor or related circuit malfunction ― MAF sensor or related circuit malfunction ― MAP sensor or related circuit malfunction ― Front HO2S or related circuit malfunction (PCM connector (2 types)) ― Rear HO2S or related circuit malfunction (PCM connector (2 types)) ― A/F sensor or related circuit malfunction (PCM connector (3 types)) ― HO2S or related circuit malfunction (PCM connector (3 types)) ― TP sensor or related circuit malfunction ― VSS or related circuit malfunction • Excessive fuel pressure ― Fuel pump mechanical malfunction ― Fuel line restriction or clogging ― Pressure regulator malfunction (built-in fuel pump unit) • Ignition system malfunction ― Ignition coil malfunction ― Ignition coil related circuit malfunction ― Spark plug malfunction • Erratic CMP sensor signal • Improper engine compression • Improper fuel injection timing and amount 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 [MZI-3.7].)(See AFTER SERVICE PRECAUTION [MZI-3.7].) Caution • Disconnecting/connecting quick release connector without cleaning it may cause 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.

EXHAUST SMOKE

DESCRIPTION

• Blue, black, or white smoke from exhaust system.

POSSIBLE CAUSE

Blue smoke (Burning oil):

• PCV valve malfunction

• Engine internal oil leakage

White smoke (Water in combustion):

• Cooling system malfunction (coolant loss)

• Engine internal coolant leakage

Black smoke (Rich fuel mixture):

• Air cleaner restriction

• Intake-air system is collapsed or restricted.

• PCM DTC is stored.

• Erratic signal to PCM

― APP sensor or related circuit malfunction

― CHT sensor or related circuit malfunction

― IAT sensor or related circuit malfunction

― MAF sensor or related circuit malfunction

― MAP sensor or related circuit malfunction

― Front HO2S or related circuit malfunction (PCM connector (2 types))

― Rear HO2S or related circuit malfunction (PCM connector (2 types))

― A/F sensor or related circuit malfunction (PCM connector (3 types))

― HO2S or related circuit malfunction (PCM connector (3 types))

― TP sensor or related circuit malfunction

― VSS or related circuit malfunction

• Excessive fuel pressure

― Fuel pump mechanical malfunction

― Fuel line restriction or clogging

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

• Ignition system malfunction

― Ignition coil malfunction

― Ignition coil related circuit malfunction

― Spark plug malfunction

• Erratic CMP sensor signal

• Improper engine compression

• Improper fuel injection timing and amount

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 [MZI-3.7].)(See AFTER SERVICE PRECAUTION [MZI-3.7].)

Caution

• Disconnecting/connecting quick release connector without cleaning it may cause 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.

STEP	INSPECTION	RESULTS	ACTION
1	What color is smoke coming from the exhaust system?	Blue	Burning oil is indicated: • Go to the next step.
White	Water in combustion is indicated: • Go to Step 3.
Black	Rich fuel mixture is indicated: • Go to Step 4.
2	Note • The PCV valve cannot be reassembled once it is removed because the tabs will have bee n broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI-3.7].) Is the PCV valve normal?	Yes	Inspect for the following: • Damaged valve guide, stems or valve seals • Blocked oil drain passage in cylinder head • Piston ring is not seated, seized or worn. • Damaged cylinder bore Repair or replace the malfunctioning part according to the inspection results. • If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7].)
3	Warning • Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator are hot. Scalding engine coolant and steam may shoot out and cause serious injury. It may also damage the engine and cooling system. • Turn off the engine and wait until it is cool. Even then, be very careful when removing the cap. Wrap a thick cloth around it and slowly turn it counterclockwise to the first stop. Step back while the pressure escapes. • When you are sure all the pressure is gone, press down on the cap using the cloth, turn it, and remove it. Does the cooling system hold pressure?	Yes	Inspect for the following: • Cylinder head gasket leakage • Intake manifold gasket leakage • Cracked or porous engine block Repair or replace the malfunctioning part according to the inspection results. • If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
4	Inspect for the following: • Air cleaner restriction • Collapsed or restricted intake-air system • Restricted fuel return line Are all items normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 4.
5	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (2 TYPES))].) (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (3 TYPES))].) Are there any DTCs displayed?	Yes	DTC is displayed: • Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7 (PCM CONNECTOR (2 TYPES))].) (See DTC TABLE [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
No	No DTC is displayed: • Go to the next step.
6	Caution • While performing this step, always operate the vehicle in a safe and lawful manner. • When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (2 TYPES))].) (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (3 TYPES))].) • APP1 • APP2 • APP3 (PCM connector (2 types)) • ECT • IAT • MAF • MAP • O2S11 • O2S21 • O2S12 • O2S22 • TP1 • TP2 • VSS Monitor the PIDs under the black smoke appeared engine condition. Do the PIDs indicate normal according to the engine conditions? (See PCM INSPECTION [MZI-3.7].)	Yes	Go to the next step.
No	APP1, APP2 or APP3 PID is not normal: • Inspect if output signal APP sensor changes smoothly. ECT PID is not normal: • Inspect intermittent short circuit of CHT sensor and related wiring harnesses. IAT PID is not normal: • Inspect for air suction in intake-air system. ― If normal, inspect intermittent short circuit of IAT sensor and related wiring harnesses. MAF PID is not normal: • Inspect for intermittent open circuit of MAF sensor and related wiring harness. MAP PID is not normal: • Inspect for intermittent open circuit of MAP sensor and related wiring harness. O2S11 or O2S21 PID is not normal: • PCM connector (2 types): ― Inspect for intermittent open circuit of suspect front HO2S and related wiring harness. • PCM connector (3 types): ― Inspect for intermittent open circuit of suspect A/F sensor and related wiring harness. O2S12 or O2S22 PID is not normal: • PCM connector (2 types): ― Inspect for intermittent open circuit of suspect rear HO2S and related wiring harness. • PCM connector (3 types): ― Inspect for intermittent open circuit of suspect HO2S and related wiring harness. TP1 or TP2 PID is not normal: • Inspect if output signal TP sensor changes smoothly. VSS PID is not normal: • Inspect for intermittent open circuit of VSS and related wiring harness. Repair or replace the malfunctioning part according to the inspection results.
7	Install the fuel pressure gauge between fuel pipe and fuel distributor. Start the engine and run it at idle. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7].) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
No	Zero or low: • Inspect the following: ― Fuel pump relay ― Fuel pump circuit ― Fuel line for clogging • If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].) High: • Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].)
8	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
9	Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7].) Is the CMP sensor normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
10	Is the engine compression correct?	Yes	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI-3.7].) Repair or replace the malfunctioning part according to the inspection results.
No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
11	• Verify test results. ― If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].) ― 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. (See PCM REMOVAL/INSTALLATION [MZI-3.7].)

STEP

INSPECTION

RESULTS

ACTION

What color is smoke coming from the exhaust system?

Blue

Burning oil is indicated:

• Go to the next step.

White

Water in combustion is indicated:

• Go to Step 3.

Black

Rich fuel mixture is indicated:

• Go to Step 4.

Note

• The PCV valve cannot be reassembled once it is removed because the tabs will have bee n broken. Inspect the PCV valve without removing it from the vehicle.

Inspect the PCV valve with it installed.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI-3.7].)

Is the PCV valve normal?

Yes

Inspect for the following:

• Damaged valve guide, stems or valve seals

• Blocked oil drain passage in cylinder head

• Piston ring is not seated, seized or worn.

• Damaged cylinder bore

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

• If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.

Replace the PCV valve.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7].)

Warning

• Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator are hot. Scalding engine coolant and steam may shoot out and cause serious injury. It may also damage the engine and cooling system.

• Turn off the engine and wait until it is cool. Even then, be very careful when removing the cap. Wrap a thick cloth around it and slowly turn it counterclockwise to the first stop. Step back while the pressure escapes.

• When you are sure all the pressure is gone, press down on the cap using the cloth, turn it, and remove it.

Does the cooling system hold pressure?

Yes

Inspect for the following:

• Cylinder head gasket leakage

• Intake manifold gasket leakage

• Cracked or porous engine block

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

• If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.

Inspect for cause.

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

Inspect for the following:

• Air cleaner restriction

• Collapsed or restricted intake-air system

• Restricted fuel return line

Are all items normal?

Yes

Go to the next step.

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

Repeat Step 4.

Turn the ignition switch to the ON position (Engine off).

Retrieve any PCM DTCs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)

(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)

Are there any DTCs displayed?

Yes

DTC is displayed:

• Go to the appropriate DTC inspection.

(See DTC TABLE [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)

(See DTC TABLE [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)

No DTC is displayed:

• Go to the next step.

Caution

• While performing this step, always operate the vehicle in a safe and lawful manner.

• When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later.

Access the following PCM PIDs using the M-MDS:

(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)

(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)

• APP1

• APP2

• APP3 (PCM connector (2 types))

• ECT

• IAT

• MAF

• MAP

• O2S11

• O2S21

• O2S12

• O2S22

• TP1

• TP2

• VSS

Monitor the PIDs under the black smoke appeared engine condition.

Do the PIDs indicate normal according to the engine conditions?

(See PCM INSPECTION [MZI-3.7].)

Yes

Go to the next step.

APP1, APP2 or APP3 PID is not normal:

• Inspect if output signal APP sensor changes smoothly.

ECT PID is not normal:

• Inspect intermittent short circuit of CHT sensor and related wiring harnesses.

IAT PID is not normal:

• Inspect for air suction in intake-air system.

― If normal, inspect intermittent short circuit of IAT sensor and related wiring harnesses.

MAF PID is not normal:

• Inspect for intermittent open circuit of MAF sensor and related wiring harness.

MAP PID is not normal:

• Inspect for intermittent open circuit of MAP sensor and related wiring harness.

O2S11 or O2S21 PID is not normal:

• PCM connector (2 types):

― Inspect for intermittent open circuit of suspect front HO2S and related wiring harness.

• PCM connector (3 types):

― Inspect for intermittent open circuit of suspect A/F sensor and related wiring harness.

O2S12 or O2S22 PID is not normal:

• PCM connector (2 types):

― Inspect for intermittent open circuit of suspect rear HO2S and related wiring harness.

• PCM connector (3 types):

― Inspect for intermittent open circuit of suspect HO2S and related wiring harness.

TP1 or TP2 PID is not normal:

• Inspect if output signal TP sensor changes smoothly.

VSS PID is not normal:

• Inspect for intermittent open circuit of VSS and related wiring harness.

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

Install the fuel pressure gauge between fuel pipe and fuel distributor.

Start the engine and run it at idle.

Measure the fuel line pressure during idle.

(See FUEL LINE PRESSURE INSPECTION [MZI-3.7].)

Is the fuel line pressure correct during idle?

Yes

Go to the next step.

Zero or low:

• Inspect the following:

― Fuel pump relay

― Fuel pump circuit

― Fuel line for clogging

• If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction)

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].)

High:

• Replace the fuel pump unit. (Pressure regulator malfunction)

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].)

Perform the spark test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].)

Is strong blue spark visible at each cylinder?

Yes

Go to the next step.

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

Inspect the CMP sensor.

(See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7].)

Is the CMP sensor normal?

Yes

Go to the next step.

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

Is the engine compression correct?

Yes

Inspect the fuel injector.

(See FUEL INJECTOR INSPECTION [MZI-3.7].)

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

Inspect for cause.

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

• Verify test results.

― If normal, return to diagnostic index to service any additional symptoms.

(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)

― 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.

(See PCM REMOVAL/INSTALLATION [MZI-3.7].)