Mazda CX-9 Grand Touring 2009 Manual page 1322

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
crankshaft pulley.
Are CKP sensor and teeth of crankshaft
15
pulley normal?
Inspect the ignition coil related wiring
harness condition (intermittent open or
16
short circuit) for all cylinders. Are wiring
harness conditions normal?
Perform the spark test.
(See ENGINE CONTROL SYSTEM
OPERATION INSPECTION [MZI-
17
3.7].)
Is strong blue spark visible at each
cylinder?
Inspect the spark plug condition.
18 Is spark plug wet, covered with carbon or
grayish white?
Remove and shake the PCV valve.
19
Does the PCV valve rattle?
visually inspect the exhaust system part.
20
Is there any deformed exhaust system part?
Install the fuel pressure gauge between the
fuel pipe and the fuel distributor.
Short check connector terminal F/P to body
GND using a jumper wiring.
Turn the ignition switch to the ON
21
position.
Is fuel line pressure correct with ignition
switch ON?
(See FUEL LINE PRESSURE
INSPECTION [MZI-3.7] .)
Visually inspect for fuel leakage at fuel
injector O-ring and fuel line.
Service if necessary.
22
Is fuel line pressure held after ignition
switch is turned off?
(See FUEL LINE PRESSURE
2008 Mazda CX-9 Grand Touring
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Go to the next step.
Replace the malfunctioning part.
Go to the next step.
Repair the wiring harnesses.
Go to the next step.
If symptoms occurs with the A/C on, go to
Step 23.
Repair or replace the malfunctioning part
according to spark test result.
Spark plug is wet or covered with
carbon:
Inspect for fuel leakage from injector.
Spark plug is grayish white:
Inspect the fuel injector for clogging.
Install spark plugs on original cylinders.
Go to the next step.
Go to the next step.
Replace the PCV valve.
Replace the suspected part.
Go to the next step.
Go to the next step.
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] .)
Go to the next step.
Inspect the fuel injector.
If the fuel injector is normal, replace the
fuel pump unit.
(See FUEL PUMP UNIT
REMOVAL/INSTALLATION [MZI-