NO.27 SPARK PLUG CONDITION [L3 R.H.D.]

id0103a4804400

27

SPARK PLUG CONDITION

DESCRIPTION

Incorrect spark plug condition

POSSIBLE CAUSE

Note
• Spark plug inspection can determine whether the problem is related to a specific cylinder or to 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 fuel system diagnosis and repair procedures. Read the following warnings before performing any fuel system-related procedures:
• 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 [L3].)
(See AFTER SERVICE PRECAUTION [L3].)
Caution
• Disconnecting/connecting quick release connector without cleaning them it may possibly cause damage to the fuel pipe or quick release connector. Always clean the quick release connector joint before disconnecting/connecting, and make sure that it is free of foreign material.

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Remove all the spark plugs.
Inspect spark plug condition.
Is 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 9.

All plugs look grayish white:

Go to Step 15.
2
Are the spark plug wet/covered with carbon due to engine oil?
Yes
Inspect all areas related to oil, working from top to bottom.
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.
4
Inspect the compression pressure at the suspected malfunctioning cylinder.
Is compression pressure correct?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part.
5
Install all spark plugs.
Perform the spark test at the suspected malfunctioning cylinder.
Is a strong blue spark visible?
(Compare with a normal cylinder.)
Yes
Go to the next step.
No
Repair or replace the malfunctioning part.
6
Perform the fuel line pressure inspection.
Is the fuel line pressure correct?
Yes
Inspect fuel injectors for the following:
• Open or short circuit in injector
• Leakage
• Injection volume
No

Zero or low:

Inspect the fuel pump, IFS switch and fuel pump relay- related circuit.
Inspect the fuel line for clogging.
• If there is no malfunction, replace the fuel pump unit.

High:

Replace the fuel pump unit.
7
Inspect the spark plug for the following.
• Heat range
• Air gap
Is the spark plug normal?
Yes
Go to the next step.
No
Replace the spark plug.
8
Remove the suspected fuel injector.
Inspect the following:
• Resistance
• Fuel injection volume
Are all above items normal?
Yes
Inspect for open circuit in wiring harness between the fuel injector terminal and PCM following terminals:
• For No.1 cylinder 82
• For No.2 cylinder 83
• For No.3 cylinder 84
• For No.4 cylinder 85
No
Replace the fuel injector.
9
Is the air cleaner element free of restrictions?
Yes
Go to the next step.
No
Replace the air cleaner element.
10
Perform the spark test.
Is a strong blue spark visible at each cylinder?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part.
11
Perform the fuel line pressure inspection.
Is fuel line pressure correct?
Yes
Go to the next step.
No

Zero or low:

Inspect the fuel pump and fuel pump, IFS switch, relay- related circuit.
Inspect the fuel line for clogging.
• If there is no malfunction, replace the fuel pump unit.

High:

Replace the fuel pump unit.
12
Inspect the following PIDs.
• ECT
• O2S11 (When engine can be started)
• O2S12 (When engine can be started)
• MAF
Are the PIDs normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part.
13
Perform the purge control inspection.
(When engine can be started)
Is the purge control correct?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part.
14
Perform the compression inspection.
Is the compression correct?
Yes
Visually inspect for deformed in exhaust system part.
No
Repair or replace the malfunctioning part.
15
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 properly suctioned by the intake-air system?
Yes
Repair or replace the malfunctioning part.
No
Go to the next step.
16
Perform the fuel line pressure inspection.
Is the fuel line pressure correct?
Yes
Inspect the following PIDs.
• ECT
• O2S11
• O2S12
• MAF
(See PCM INSPECTION [L3 R.H.D.].)
Inspect the PCM GND condition.
No

Zero or low:

Inspect the fuel pump, IFS switch and fuel pump relay related circuit.
Inspect the fuel line for clogging.
• If there is no malfunction, replace the fuel pump unit.

High:

Replace the fuel pump unit.
17
Verify test results.
• If normal, return to the diagnostic index to service any additional symptoms.
• If any malfunction remains, inspect related service information, and 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 [L3].)