Mazda CX-9 Grand Touring. Manual — part 346

DIAGNOSTIC PROCEDURE

NO.28 FUEL FILLING SHUT OFF CONCERNS (MZI-3.7) DIAGNOSTIC PROCEDURE

POSSIBLE

CAUSE

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 [MZI-3.7] .)

(See AFTER SERVICE PRECAUTION [MZI-3.7] .)

CAUTION:



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

STEP

INSPECTION

ACTION

1

Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON position
(Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?

Yes

DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [MZI-3.7] .)

No

No DTC is displayed:

Go to the next step.

2

Remove the fuel-filler pipe.
Make sure the nonreturn valve is installed
properly.
Inspect nonreturn valve operation.
Is the nonreturn valve normal?

Yes

Inspect for the following:



Improper use of fuel nozzle



Fuel is not inserted correctly.



Inspect fuel shut-off valve.

No

Nonreturn valve is installed improperly:



Reinstall the nonreturn valve to proper

position.

Nonreturn valve does not operate properly:



Replace the nonreturn valve.



Verify test results.



If normal, return to diagnostic index to service any additional symptoms.

(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

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© 2005 Mitchell Repair Information Company, LLC.

NO.29 SPARK PLUG CONDITION [MZI-3.7]

NO.29 SPARK PLUG CONDITION (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES

3



If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.



If vehicle is repaired, troubleshooting completed.



If vehicle is not repaired or additional diagnostic information is not available,
replace the PCM.

(See PCM REMOVAL/INSTALLATION [MZI-3.7] .)

29

SPARK PLUG CONDITION

DESCRIPTION Incorrect spark plug condition

POSSIBLE

CAUSE

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



Compression-Low compression



Clogging in intake/exhaust system

Grayish white with all plugs:



Air/fuel mixture-Too lean

NOTE:



Inspecting spark plugs condition can determine whether problem is related
to a specific cylinder or possibly all cylinders.

WARNING:

The following troubleshooting flow chart contains the fuel system diagnosis

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

Page 91

© 2005 Mitchell Repair Information Company, LLC.

DIAGNOSTIC PROCEDURE

NO.29 SPARK PLUG CONDITION (MZI-3.7) DIAGNOSTIC PROCEDURE

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 [MZI-3.7] .)

(See AFTER SERVICE PRECAUTION [MZI-3.7] .)

CAUTION:



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

STEP

INSPECTION

RESULTS

ACTION

1

Remove all the spark plugs.
Inspect spark plug condition.
Is spark plug condition normal?

Yes

Troubleshooting completed.

No

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.

2

Are the spark plug wet/covered
with carbon by the engine oil?

Yes

Inspect all areas related to oil, working up and
down.

No

Go to the next step.

3

Inspect the spark plug for the
following:



Cracked insulator



Heat range



Air gap



Worn electrode

Yes

Go to the next step.

No

Replace the spark plug.

(See SPARK PLUG

REMOVAL/INSTALLATION [MZI-3.7] .)

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

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© 2005 Mitchell Repair Information Company, LLC.

Is the spark plug normal?

4

Inspect compression pressure at
suspected malfunctioning
cylinder.
Is compression pressure correct?
(See COMPRESSION
INSPECTION [MZI-3.7] .)

Yes

Go to the next step.

No

Repair or replace the malfunctioning part.

5

Install all spark plugs.
Perform the spark test at suspected
malfunctioning cylinder.
Is strong blue spark visible?
(Compare with normal cylinder.)

Yes

Go to the next step.

No

Repair or replace the malfunctioning part.

6

Install the fuel pressure gauge
between fuel filter and fuel
distributor.
Short check connector terminal
F/P to body GND using a jumper
wiring.
Turn the ignition switch to the ON
position (Engine off).
Is the fuel line pressure correct
with the ignition switch at ON?
(See FUEL LINE PRESSURE
INSPECTION [MZI-3.7] .)

Yes

Inspect fuel injector for the following:



Open or short circuit in injector



Leakage



Injection volume

No

Zero or low:

Inspect the fuel pump relay and fuel pump circuit.

Inspect the fuel line for clogging.

If there is no malfunction, replace the fuel pump

unit.

(See FUEL PUMP UNIT

REMOVAL/INSTALLATION [MZI-3.7] .)

High:

Replace the fuel pump unit.

(See FUEL PUMP UNIT

REMOVAL/INSTALLATION [MZI-3.7] .)

7

Inspect the spark plug for the
following.



Heat range



Air gap

Is the spark plug normal?

Yes

Go to the next step.

No

Replace the spark plug.

(See SPARK PLUG

REMOVAL/INSTALLATION [MZI-3.7] .)

8

Remove the suspected fuel
injector.
Inspect the following:



Resistance



Fuel injection volume

(See FUEL INJECTOR

Yes

Inspect for open circuit in wiring harness between
fuel injector connector terminal A and PCM at the
following terminals:



For No.1 cylinder: 2BJ



For No.2 cylinder: 2BM



For No.3 cylinder: 2BF

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

Page 93

© 2005 Mitchell Repair Information Company, LLC.