Spark Plug Condition: Outline
SPARK PLUG CONDITION (SKYACTIV-G 2.5T) 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-Spark weak
- Air/fuel mixture-Too rich, excessive fuel line pressure
- PCM input input signal error
- ECT sensor No. 1 or related wiring harness malfunction
- ECT sensor No. 2 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
- EGR system malfunction
- Restriction in intake/exhaust system
Grayish white with all plugs:
- PCM input input signal error
- ECT sensor No. 1 or related wiring harness malfunction
- ECT sensor No. 2 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
- EGR system 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 [SKYACTIV-G 2.5T]
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 the [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 [SKYACTIV-G 2.5T]
in service information.) (Refer to AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5T]
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.
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| System wiring diagram |
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