NO.27 SPARK PLUG CONDITION [L8, LF]

id0103a0804400

27 | SPARK PLUG CONDITION
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DESCRIPTION | • Incorrect spark plug condition.
POSSIBLE CAUSE | Note • Inspecting spark plugs condition can determine whether problem is related to a specific cylinder possibly all cylinders. Wet/carbon stuck on specific plug: • Spark—Weak, not visible • Compression—No compression, low compression • Spark plug malfunction • Air/fuel mixture—Excessive fuel injection volume Grayish white with specific plug: • Spark plug malfunction • Air/fuel mixture—Insufficient fuel injection volume Wet/carbon is stuck on all plugs: • Air/fuel mixture—Too rich • Spark—Spark weak • Clogging in intake/exhaust system • Compression—Low compression Grayish white with all plugs: • Air/fuel mixture—Too lean Other: • PCM 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 “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 | Remove all the spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION [L8, LF].) Inspect the spark plug. (See SPARK PLUG INSPECTION [L8, LF].) Is there any malfunction? | Yes | Specific plug is wet or covered with carbon: • Go to the next step. Specific plug looks grayish white: • Go to Step 7. All plugs are wet or covered with carbon: • Go to Step 9. All plugs look grayish white: • Go to Step 15.
No | Symptom troubleshooting completed.
2 | Are the spark plug wet/covered with carbon by engine oil? | Yes | Inspect the all areas related to oil, working up and down. Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
3 | Inspect the spark plug for following: • Air gap • Cracked insulator • Heat range • Worn electrode Is there any malfunction? | Yes | Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION [L8, LF].)
No | Go to the next step.
4 | Perform the “COMPRESSION INSPECTION”. (See COMPRESSION INSPECTION [L8, LF].) Is the engine compression correct? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
5 | Install all spark plugs. Perform the Spark Test at suspected malfunction cylinder. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF].) Is the strong blue spark visible? (Compare with normal cylinder.) | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
6 | Perform the “FUEL LINE PRESSURE INSPECTION”. (See FUEL LINE PRESSURE INSPECTION [L8, LF].) Is the fuel line pressure correct? | Yes | Inspect the fuel injector for following: • Injection volume • Leakage • Open or short circuit in injector Repair or replace the malfunctioning part according to the inspection results.
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 | Inspect the spark plug for following: • Air gap • Heat range Is there any malfunction? | Yes | Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION [L8, LF].)
No | Go to the next step.
8 | Remove the suspected fuel injector. (See FUEL INJECTOR REMOVAL/INSTALLATION [L8, LF].) Inspect the following: (See FUEL INJECTOR INSPECTION [L8, LF].) • Resistance • Fuel injection volume Is there any malfunction? | Yes | Replace the fuel injector. (See FUEL INJECTOR REMOVAL/INSTALLATION [L8, LF].)
No | Inspect the wiring harness between fuel injector terminal B and PCM following terminals for open circuit: • For No.1 cylinder terminal 2BB • For No.2 cylinder terminal 2BC • For No.3 cylinder terminal 2BD • For No.4 cylinder terminal 2AZ Repair or replace the suspected wiring harness.
9 | Is the air cleaner element free of restrictions? | Yes | Go to the next step.
No | Replace the air cleaner element. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [L8, LF].)
10 | Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF].) Is the 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.
11 | Perform the “FUEL LINE PRESSURE INSPECTION”. (See FUEL LINE PRESSURE INSPECTION [L8, LF].) Is the fuel line pressure correct? | 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].)
12 | Connect the M-MDS to the DLC-2. Perform the PID/DATA Monitor and Record Procedure and access the following PIDs: (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) • ECT • MAF • O2S11 (When engine can be started) • O2S12 (When engine can be started) Are the PIDs normal? (See PCM INSPECTION [L8, LF].) | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
13 | Perform the Purge Control System Inspection (when the engine can be started). (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF].) Is the purge control system correct? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
14 | Perform the “COMPRESSION INSPECTION”. (See COMPRESSION INSPECTION [L8, LF].) Is the engine compression correct? | Yes | Visually inspect for deformed in exhaust system part. Repair or replace the malfunctioning part according to the inspection results.
No | Repair or replace the malfunctioning part according to the inspection results.
15 | When the engine cannot be started: • Inspect intake-air system for air leakage. When the engine can be started: • Perform the Intake Manifold Vacuum Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF].) Is the air sucked in from the intake-air system? | Yes | Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
16 | Perform the “FUEL LINE PRESSURE INSPECTION”. (See FUEL LINE PRESSURE INSPECTION [L8, LF].) Is the fuel line pressure correct? | 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].)
17 | Connect the M-MDS to the DLC-2. Perform the PID/DATA Monitor and Record Procedure and access the following PIDs: (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) • ECT • MAF • O2S11 (When engine can be started) • O2S12 (When engine can be started) Are the PIDs normal? (See PCM INSPECTION [L8, LF].) | Yes | Inspect PCM ground condition. Repair or replace the malfunctioning part according to the inspection results.
No | Repair or replace the malfunctioning part according to the inspection results.
18 | 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].)