NO.27 SPARK PLUG CONDITION [ZJ, Z6]

#
NO.27 SPARK PLUG CONDITION [ZJ, Z6]

B3E010318881W60

27 | SPARK PLUG CONDITION
--- | ---
DESCRIPTION | Incorrect spark plug condition

POSSIBLE CAUSE

  Note

  • Inspecting spark plug condition can determine whether problem is related to a specific cylinder possibly all cylinders.

Wet/carbon stuck on specific plug:
• Spark-Weak, not visible
• Air/fuel mixture-Excessive fuel injection volume
• Compression-No compression, low compression
• Malfunctioning spark plug
Grayish white with specific plug:
• Air/fuel mixture-Insufficient fuel injection volume
• Malfunctioning spark plug
Wet/carbon is stuck on all plugs:
• Spark-Spark weak
• Air/fuel mixture-Too rich
• Compression-Low compression
• Clogging in intake/exhaust system
Grayish white with all plugs:
• Air/fuel mixture-Too lean

  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 | Remove all the spark plugs. Inspect the spark plug condition. Is the spark plug condition normal? | Yes | Troubleshooting completed.

No

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 10.

All plugs look grayish white:

Go to Step 16.

2 | Are the spark plugs wet/covered with carbon by engine oil? | Yes | Inspect all areas related to oil working up and down.
No | Go to the next step.

3

Inspect the spark plug for the following:
• Cracked insulator
• Heat range
• Air gap
• Worn electrode
Is the spark plug normal?

Yes

Go to the next step.

No | Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION [ZJ, Z6].)
4 | Inspect compression pressure at suspected malfunctioning cylinder. Is compression pressure correct? (See COMPRESSION INSPECTION [ZJ, Z6].) | Yes | Go to the next step.
No | Repair or replace the malfunctioning part.
5 | Install all spark plugs. Perform the spark test at suspected malfunctioning cylinder. Is strong blue spark visible? (See Spark Test.) (Compare with normal cylinder.) | Yes | Go to the next step.
No | Repair or replace the malfunctioning part.
6 | Perform the fuel line pressure inspection. (See FUEL LINE PRESSURE INSPECTION [ZJ, Z6, LF].) Is fuel line pressure correct? | Yes | Inspect the fuel injector for following: • Open or short circuit in injector • Leakage • Injection volume

No

Zero or low:

Inspect fuel pump and the fuel pump relay related circuit.
Inspect the main fuel line for clogging.
• If normal, replace 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].)

7 | Inspect the spark plug for following. • Heat range • Air gap Is spark plug normal? | Yes | Go to the next step.
No | Replace the spark plug.
8 | Turn the ignition switch off. Disconnect suspected fuel injector connector. Turn the ignition switch to the ON position. Measure terminal voltage for the fuel injector terminal A. Is voltage B+? | Yes | Go to the next step.
No | Repair open or short fuel injector power supply circuit.

9

Turn the ignition switch off.
Disconnect the PCM connector.
Measure resistance between suspected the fuel injector terminal B and the PCM connector following terminal:
• For No.1 cylinder: 2B
• For No.2 cylinder: 2C
• For No.3 cylinder: 2D
• For No.4 cylinder: 2H
Is resistance less than 5.0 ohms?

Yes

Inspect the fuel injector for following:
(See FUEL INJECTOR INSPECTION [ZJ, Z6, LF].)
• Resistance
• Fuel injection volume

No | Repair open the fuel injector control circuit.
10 | Is the air cleaner element free of restrictions? | Yes | Go to the next step.
No | Replace the air cleaner element.
11 | Perform the spark test. Is strong blue spark visible at each cylinder? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part.
12 | Perform the fuel line pressure inspection. 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 and fuel pump relay related circuit.
Inspect the main fuel line for clogging.
• If normal, replace 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].)

13

Inspect the following PIDs.
• ECT
• O2S11 (When engine can be started)
• MAF
(See PCM INSPECTION [ZJ, Z6].)
Are PIDs normal?

Yes

Go to the next step.

No | Repair or replace the malfunctioning part.
14 | Perform the purge control inspection. (When engine can be started) (See Purge Control System Inspection.) Is purge control correct? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part.
15 | Perform the compression inspection. Is compression correct? | Yes | Inspect for deformed exhaust system part.
No | Repair or replace the malfunctioning part.
16 | When the engine cannot be started, inspect the intake-air system for air leakage. When the engine can be started, perform the intake manifold vacuum inspection. Is air sucked in from intake-air system? | Yes | Repair or replace the malfunctioning part.
No | Go to the next step.

17

Perform the fuel line pressure inspection.
Is fuel line pressure correct?
(See FUEL LINE PRESSURE INSPECTION [ZJ, Z6, LF].)

Yes

Inspect following PIDs:
• ECT
• O2S11
• O2S12
• MAF

  (See PCM INSPECTION [ZJ, Z6].)

Inspect PCM GND condition.

No

Zero or low:

Inspect the fuel line for clogging.
• If there is no malfunction, 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].)

18

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 PCM.
  (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [ZJ, Z6].)