Spark Plug Condition [PYUL]: Outline

WARNING: This page is about a different variant/trim than selected.

SPARK PLUG CONDITION (PYUL) DESCRIPTION AND POSSIBLE CAUSE

Troubleshooting item	Spark plug condition
Description	Incorrect spark plug condition.
Possible cause	NOTE: Inspecting the spark plug conditions can determine whether a problem is related to a specific cylinder or 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 Malfunction spark plug Grayish white with specific plug: Air/fuel mixture-Insufficient fuel injection volume Spark plug malfunction If a spark plug on a specific cylinder is damaged or corroded: Spark plug malfunction Damage or corrosion due to pre-ignition or knocking Wet/carbon is stuck on all plugs: Spark weak Air/fuel mixture-Too rich, excessive fuel line pressure PCM input signal error ECT sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction A/F sensor or related wiring harness malfunction HO2S or related wiring harness malfunction Compression-Low compression Restriction in intake/exhaust system Grayish white with all plugs: PCM input signal error ECT sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction A/F sensor or related wiring harness malfunction HO2S or related wiring harness malfunction Air/fuel mixture-Too lean, insufficient fuel line pressure 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. Highly pressurized fuel may spray out if the fuel line is cut. Due to the following dangers occurring with a fuel spray, always complete the [Fuel Line Safety Procedure] to prevent the fuel from spraying. (Refer to [ BEFORE SERVICE PRECAUTION ] in Service Information.) Fuel may cause irritation if it comes in contact with skin and eyes. If fuel ignites and causes a fire, it may lead to serious injury or death, and damage to property and facilities. Fuel is highly flammable and dangerous. Fuel line spills and leakage can cause serious injury or death, and damage to equipment. Always Refer to [ QUICK RELEASE CONNECTOR REMOVAL/INSTALLATION (FUEL SYSTEM) ] before performing the fuel hose installation, and execute the [Fuel Leakage Inspection] after installation. (Refer to [ QUICK RELEASE CONNECTOR (FUEL SYSTEM) REMOVAL/INSTALLATION ] in Service Information). (Refer to [ AFTER SERVICE PRECAUTION ] in Service Information.) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.
System wiring diagram	Not applicable

Troubleshooting item

Spark plug condition

Description

Incorrect spark plug condition.

Possible cause

NOTE:

Inspecting the spark plug conditions can determine whether a problem is related to a specific cylinder or 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
Malfunction spark plug

Grayish white with specific plug:

Air/fuel mixture-Insufficient fuel injection volume
Spark plug malfunction

If a spark plug on a specific cylinder is damaged or corroded:

Spark plug malfunction
- Damage or corrosion due to pre-ignition or knocking

Wet/carbon is stuck on all plugs:

Spark weak
Air/fuel mixture-Too rich, excessive fuel line pressure
PCM input signal error
- ECT sensor or related wiring harness malfunction
- MAF sensor or related wiring harness malfunction
- A/F sensor or related wiring harness malfunction
- HO2S or related wiring harness malfunction
Compression-Low compression
Restriction in intake/exhaust system

Grayish white with all plugs:

PCM input signal error
- ECT sensor or related wiring harness malfunction
- MAF sensor or related wiring harness malfunction
- A/F sensor or related wiring harness malfunction
- HO2S or related wiring harness malfunction
Air/fuel mixture-Too lean, insufficient fuel line pressure

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.
- Highly pressurized fuel may spray out if the fuel line is cut. Due to the following dangers occurring with a fuel spray, always complete the [Fuel Line Safety Procedure] to prevent the fuel from spraying. (Refer to [ BEFORE SERVICE PRECAUTION ] in Service Information.)
  - Fuel may cause irritation if it comes in contact with skin and eyes.
  - If fuel ignites and causes a fire, it may lead to serious injury or death, and damage to property and facilities.
- Fuel is highly flammable and dangerous. Fuel line spills and leakage can cause serious injury or death, and damage to equipment. Always Refer to [ QUICK RELEASE CONNECTOR REMOVAL/INSTALLATION (FUEL SYSTEM) ] before performing the fuel hose installation, and execute the [Fuel Leakage Inspection] after installation. (Refer to [ QUICK RELEASE CONNECTOR (FUEL SYSTEM) REMOVAL/INSTALLATION ] in Service Information). (Refer to [ AFTER SERVICE PRECAUTION ] in Service Information.)

CAUTION:

Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

System wiring diagram

Not applicable