NO.19 EXHAUST SMOKE [L8, LF]

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19 | EXHAUST SMOKE
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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 • Fuel return line is restricted • Excessive fuel pressure • Improper engine compression • Inadequate fuel pressure • Ignition system malfunction • CMP sensor malfunction Other: • PCM malfunction Warning The following troubleshooting flow chart contains fuel system diagnosis and repair procedures. Read following warnings before performing 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. (See BEFORE SERVICE PRECAUTION [L8, LF].) (See AFTER SERVICE PRECAUTION [L8, LF].) Caution • Disconnecting/connecting quick release connector without cleaning it may possibly 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.

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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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 | Inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [L8, LF].) Is there any malfunction? | Yes | Replace the PCV valve.
No | Inspect the following: • Blocked oil drain passage in cylinder head • Damaged cylinder bore • Damaged valve guide, stems or valve seals • Piston ring is not seated, seized or worn 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.
3 | Does the cooling system hold pressure? | Yes | Inspect for the following: • Cracked or porous engine block • Cylinder head gasket leakage • Intake manifold gasket leakage 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.
4 | Inspect the following: • Air cleaner restriction • Collapsed or restricted intake-air system • Restricted fuel return line Is there any malfunction? | Yes | Repair or replace the malfunctioning part according to the inspection results. Repeat Step 4.
No | Go to the next step.
5 | Connect the M-MDS to the DLC-2. Perform the KOEO/KOER self test and the DTC Reading Procedure. (See KOEO/KOER SELF TEST [L8, LF].) (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) Are any DTCs present? | Yes | Go to the appropriate DTC inspection. (See DTC TABLE [L8, LF].)
No | Go to the next step.
6 | Install fuel pressure gauge between the fuel pipe and fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [L8, LF].) Is fuel line pressure correct during idle? | Yes | Go to the next step.
No | Zero or low: • Inspect the fuel pump and fuel pump relay related circuit. • Inspect for clogged fuel line. • If there is no malfunction: ― Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [L8, LF].) • If there is a malfunction: ― Repair or replace the malfunctioning part according to the inspection results. High: • Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [L8, LF].)
7 | Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF].) Is strong blue spark visible at each cylinder? | Yes | Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L8, LF].) Replace the CMP sensor, if necessary. (See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [L8, LF].)
No | Repair or replace the malfunctioning part according to the inspection results.
8 | Verify test results. • If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [L8, LF].) • 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 PCM REMOVAL/INSTALLATION [L8, LF].)