NO.27 SPARK PLUG CONDITION [MZR 1.8, MZR 2.0, MZR 2.5]

id0103d4804400

27

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
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
•  Clogging in intake/exhaust system
Grayish white with all plugs:
•  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 servicing the fuel system:
―  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 [MZR 1.8, MZR 2.0, MZR 2.5].) (See AFTER SERVICE PRECAUTION [MZR 1.8, MZR 2.0, MZR 2.5].)
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
Remove all spark plugs.
(See SPARK PLUG REMOVAL/INSTALLATION [MZR 1.8, MZR 2.0, MZR 2.5].)
Inspect the spark plug.
(See SPARK PLUG INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
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
Are the spark plugs wet/covered with carbon from the engine oil?
Yes
Inspect all areas related to oil, working up and down.
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
3
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 [MZR 1.8, MZR 2.0, MZR 2.5].)
No
Go to the next step.
4
Inspect the compression pressure at the suspected cylinder.
(See COMPRESSION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
5
Reinstall all spark plugs.
(See SPARK PLUG REMOVAL/INSTALLATION [MZR 1.8, MZR 2.0, MZR 2.5].)
Perform the Spark Test at the suspected cylinder.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
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 the fuel line pressure.
(See FUEL LINE PRESSURE INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Is there any malfunction?
Yes
Zero or low:
•  Inspect the fuel pump relay and the fuel pump circuit.
•  Inspect the fuel line for clogging.
―  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.
High:
•  Replace the fuel pump unit.
No
Inspect the fuel injector for the following:
•  Injection volume
•  Leakage
•  Open or short circuit in injector
Repair or replace the malfunctioning part according to the inspection results.
7
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 [MZR 1.8, MZR 2.0, MZR 2.5].)
No
Go to the next step.
8
Perform the Fuel Injector Operation Inspection.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
9
Is the air cleaner element free of clogging?
Yes
Go to the next step.
No
Replace the air cleaner element.
10
Perform the Spark Test.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
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.
11
Inspect the fuel line pressure.
(See FUEL LINE PRESSURE INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Is there any malfunction?
Yes
Zero or low:
•  Inspect the fuel pump relay and the fuel pump circuit.
•  Inspect the fuel line for clogging.
―  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.
High:
•  Replace the fuel pump unit.
No
Go to the next step.
12
Access the following PIDs using the M-MDS:
(See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].)
•  ECT
•  MAF
•  O2S11 (When engine can be started)
•  O2S12 (When engine can be started)
Are the PIDs normal?
(See PCM INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Yes
Go to the next step.
No
ECT PID is not specified:
•  Inspect for an intermittent open circuit of the ECT sensor and the related wiring harness.
MAF PID is not specified:
•  Inspect for an intermittent open circuit of the MAF sensor and the related wiring harness.
O2S11 PID is not specified:
•  Inspect for an intermittent open circuit of the A/F sensor and the related wiring harness.
O2S12 PID is not 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.
13
Perform the Purge Control System Inspection when the engine can be started.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
14
Perform the compression inspection.
(See COMPRESSION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Visually inspect for deformed exhaust system parts.
Repair or replace the malfunctioning part according to the inspection results.
15
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 sucked in from intake air system?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
16
Inspect the fuel line pressure.
(See FUEL LINE PRESSURE INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Is there any malfunction?
Yes
Zero or low:
•  Inspect the fuel pump relay and the fuel pump circuit.
•  Inspect the fuel line for clogging.
―  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.
High:
•  Replace the fuel pump unit.
No
Go to the next step.
17
Access the following PIDs using the M-MDS:
(See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].)
•  ECT
•  MAF
•  O2S11 (When engine can be started)
•  O2S12 (When engine can be started)
Are the PIDs normal?
(See PCM INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)
Yes
Inspect the PCM ground condition.
Repair or replace the malfunctioning part according to the inspection results.
No
Repair or replace the malfunctioning part according to the inspection results.
18
Verify test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If the 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, reprogram the PCM if a later calibration is available. Retest.