NO.27 SPARK PLUG CONDITION [MZR 1.3, MZR 1.5]

id0103d7804400

27

SPARK PLUG CONDITION
DESCRIPTION
•  Incorrect spark plug condition.
POSSIBLE CAUSE
Note
•  Inspecting the spark plug condition can determine whether problem is related to a specific cylinder 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
•  Spark plug malfunction
Grayish white with specific plug:
•  Air/fuel mixture—Insufficient fuel injection volume
•  Spark plug malfunction
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 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
•  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 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.
•  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 1.3, MZR 1.5].) (See AFTER SERVICE PRECAUTION [MZR 1.3, MZR 1.5].)
Caution
•  Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to 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.

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 10.
All plugs look grayish white:
•  Go to Step 16.
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.
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 [MZR 1.3, MZR 1.5].)
No
Go to the next step.
4
INSPECT ENGINE COMPRESSION
•  Inspect the compression pressure at the suspected cylinder.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
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 there any malfunction?
Yes
Zero or low:
•  Inspect the fuel pump and fuel pump relay related wiring harness.
―  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)
No
Inspect the fuel injector.
(See FUEL INJECTOR INSPECTION [MZR 1.3, MZR 1.5].)
Replace the fuel injector, if necessary.
(See FUEL INJECTOR REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].)
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 [MZR 1.3, MZR 1.5].)
No
Go to the next step.
8
INSPECT FUEL INJECTOR POWER SUPPLY VOLTAGE
•  Turn the ignition switch off.
•  Disconnect the suspected fuel injector connector.
•  Turn the ignition switch to the ON position (engine off).
•  Measure the voltage at the fuel injector terminal A (wiring harness-side).
•  Is the voltage B+?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open or short circuit.
9
INSPECT FUEL INJECTOR OPERATION
•  Perform the Fuel Injector Operation Inspection.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
10
INSPECT AIR CLEANER ELEMENT
•  Inspect the air cleaner element.
•  Is the air cleaner element clean?
Yes
Go to the next step.
No
Replace the air cleaner element.
11
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.
12
INSPECT FUEL LINE PRESSURE
•  Inspect the fuel line pressure.
•  Is there any malfunction?
Yes
Zero or low:
•  Inspect the fuel pump and fuel pump relay related wiring harness.
•  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)
No
Go to the next step.
13
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.
14
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.
15
INSPECT ENGINE COMPRESSION
•  Inspect the engine compression.
•  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.
16
INSPECT INTAKE-AIR SYSTEM FOR AIR SUCTION
•  Inspect the intake-air system for air leakage and perform the Intake Manifold Vacuum Inspection when the engine cannot be started.
•  Is the 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.
17
INSPECT FUEL LINE PRESSURE
•  Inspect the fuel line pressure.
•  Is there any malfunction?
Yes
Zero or low:
•  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)
No
Go to the next step.
18
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
Inspect the PCM ground condition.
Repair or replace the malfunctioning part according to the inspection results.
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.
19
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, replace the PCM.