NO.26 SPARK PLUG CONDITION [SKYACTIV-G 2.5T]

id0103q4903100

26

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
•  Malfunction spark plug
If a spark plug on a specific cylinder is damaged or corroded:
•  Malfunction spark plug
?  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
•  Erratic signal to PCM
?  ECT sensor or related circuit malfunction
?  MAF sensor or related circuit malfunction
?  A/F sensor or related circuit malfunction
?  HO2S or related circuit malfunction
•  Compression—Low compression
•  Restriction in intake/exhaust system
Grayish white with all plugs:
•  Erratic signal to PCM
?  ECT sensor or related circuit malfunction
?  MAF sensor or related circuit malfunction
?  A/F sensor or related circuit malfunction
?  HO2S or related circuit 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. (See BEFORE SERVICE PRECAUTION [SKYACTIV-G 2.5T].)
•  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. (See QUICK RELEASE CONNECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5T].)
Caution
•  Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION
1
VERIFY SPARK PLUG CONDITION
•  Remove all spark plugs.
•  Inspect the spark plug.
•  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
DETERMINE IF MALFUNCTION CAUSE IS ENGINE OIL LOSS OR OTHER
•  Are the spark plugs wet/covered with carbon from the engine oil?
Yes
Inspect all areas related to oil, working up and down.
•  If there is any malfunction:
?  Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
3
INSPECT SPARK PLUG
•  Inspect the spark plugs for the following:
?  Air gap
?  Cracked insulator
?  Heat range
?  Worn electrode
•  Is there any malfunction?
Yes
Replace the spark plug.
(See SPARK PLUG REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
No
Go to the next step.
4
INSPECT ENGINE COMPRESSION
•  Inspect the compression pressure at the suspected cylinder.
•  Are compression pressures within specification?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
5
INSPECT IGNITION SYSTEM OPERATION
•  Reinstall all spark plugs.
•  Perform the Spark Test at the suspected cylinder.
•  Is a 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
INSPECT FUEL LINE PRESSURE
•  Inspect the fuel line pressure.
•  Is the low side fuel pressure within specification?
Specification:
•  545—695 kPa {5.56—7.08 kgf/cm2, 79.1—100.0 psi}
Yes
Inspect the fuel injector for the following:
•  Injection volume
•  Leakage
•  Open or short circuit in fuel injector
?  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
No
Zero or low:
•  Inspect the fuel pump relay and the fuel pump circuit.
•  Inspect the fuel line for restriction.
?  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
?  If there is no malfunction:
•  Replace the fuel pump unit. (Pressure regulator or fuel pump malfunction)
High:
•  Replace the fuel pump unit. (Pressure regulator malfunction)
7
INSPECT SPARK PLUG
•  Inspect the spark plug for the following:
?  Air gap
?  Heat range
•  Is there any malfunction?
Yes
Replace the spark plug.
(See SPARK PLUG REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
No
Go to the next step.
8
INSPECT FUEL INJECTOR OPERATION
•  Perform the Fuel Injector Operation Inspection.
•  Do the fuel injectors operate properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
9
INSPECT AIR CLEANER ELEMENT
•  Is the air cleaner element clean?
Yes
Go to the next step.
No
Replace the air cleaner element.
(See.AIR CLEANER ELEMENT REMOVAL/INSTALLATION [SKYACTIV-G 2.5T] )
10
VERIFY CURRENT INPUT SIGNAL STATUS
•  Access the following PIDs using the M-MDS:
?  ECT
?  MAF
?  O2S11 (When engine can be started)
?  O2S12 (When engine can be started)
•  Are the PIDs normal?
Yes
Go to the next step.
No
ECT PID is not as specified:
•  Inspect for an intermittent open circuit of the ECT sensor and the related wiring harness.
MAF PID is not as specified:
•  Inspect for an intermittent open circuit of the MAF sensor and the related wiring harness.
O2S11 PID is not as specified:
•  Inspect for an intermittent open circuit of the A/F sensor and the related wiring harness.
O2S12 PID is not as specified:
•  Inspect for an intermittent open circuit of the HO2S and the related wiring harness.
Repair or replace the malfunctioning part according to the inspection results.
11
INSPECT PURGE CONTROL SYSTEM OPERATION
•  Perform the Purge Control System Inspection when the engine can be started.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
12
INSPECT IGNITION SYSTEM OPERATION
•  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 according to the inspection results.
13
INSPECT ENGINE COMPRESSION
•  Measure the compression pressure for each cylinder.
•  Are compression pressures within specification?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
14
INSPECT FUEL LINE PRESSURE
•  Inspect the fuel line pressure.
•  Is the low side fuel pressure within specification?
Specification:
•  545—695 kPa {5.56—7.08 kgf/cm2, 79.1—100.0 psi}
Yes
Visually inspect for deformed exhaust system parts.
•  If there is any malfunction:
?  Repair or replace the malfunctioning part according to the inspection results.
No
Zero or low:
•  Inspect the fuel pump relay and the fuel pump circuit.
•  Inspect the fuel line for restriction.
?  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
?  If there is no malfunction:
•  Replace the fuel pump unit. (Pressure regulator or fuel pump malfunction)
High:
•  Replace the fuel pump unit. (Pressure regulator malfunction)
15
VERIFY CURRENT INPUT SIGNAL STATUS
•  Access the following PIDs using the M-MDS:
?  ECT
?  MAF
?  O2S11 (When engine can be started)
?  O2S12 (When engine can be started)
•  Are the PIDs normal?
Yes
Go to the next step.
No
ECT PID is not as specified:
•  Inspect for an intermittent open circuit of the ECT sensor and the related wiring harness.
MAF PID is not as specified:
•  Inspect for an intermittent open circuit of the MAF sensor and the related wiring harness.
O2S11 PID is not as specified:
•  Inspect for an intermittent open circuit of the A/F sensor and the related wiring harness.
O2S12 PID is not as specified:
•  Inspect for an intermittent open circuit of the HO2S and the related wiring harness.
Repair or replace the malfunctioning part according to the inspection results.
16
INSPECT INTAKE-AIR SYSTEM FOR AIR SUCTION
•  If the engine cannot be started:
?  Inspect the intake air system for air leakage.
•  If the engine can be started:
?  Perform the Intake Manifold Vacuum Inspection.
•  Is air being sucked in from intake air system?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
17
INSPECT FUEL LINE PRESSURE
•  Inspect the fuel line pressure.
•  Is the low side fuel pressure within specification?
Specification:
•  545—695 kPa {5.56—7.08 kgf/cm2, 79.1—100.0 psi}
Yes
Inspect the PCM ground condition.
•  If there is any malfunction:
?  Repair or replace the malfunctioning part according to the inspection results.
No
Zero or low:
•  Inspect the fuel pump relay and the fuel pump circuit.
•  Inspect the fuel line for restriction.
?  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
?  If there is no malfunction:
•  Replace the fuel pump unit. (Pressure regulator or fuel pump malfunction)
High:
•  Replace the fuel pump unit. (Pressure regulator malfunction)
18
Verify the test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If a malfunction remains, inspect the related Service Information and perform the 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.