Mazda CX-9 Grand Touring 2009 Manual page 1336

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
the engine and idle it.Access PSP PID.Is
PSP PID within specification?
Visually inspect the CKP sensor and teeth
of crankshaft pulley.
8
Are the CKP sensor and teeth of crankshaft
pulley normal?
Inspect the ignition coil related wiring
harness condition (intermittent open or
9
short circuit) for all cylinders. Are wiring
harness conditions normal?
Inspect the spark plug condition.
10 Is the spark plug wet, covered with carbon
or grayish white?
Perform the electronic throttle control
system operation inspection.
(See ENGINE CONTROL SYSTEM
11 OPERATION INSPECTION [MZI-
3.7].)
Does the electronic throttle control system
function properly?
Install fuel pressure gauge between fuel
pipe and fuel distributor.
Start the engine and run it at idle.
12 Measure fuel line pressure during idle.
Is fuel line pressure correct during idle?
(See FUEL LINE PRESSURE
INSPECTION [MZI-3.7] .)
Visually inspect for fuel leakage at fuel
injector, O-ring, and fuel line.
Service if necessary.
13 Does fuel line pressure hold after ignition
switch is turned off?
(See FUEL LINE PRESSURE
INSPECTION [MZI-3.7] .)
2008 Mazda CX-9 Grand Touring
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Go to the next step.
Replace the malfunctioning part.
Go to the next step.
Repair the wiring harnesses.
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 the spark plugs on original
cylinders.
Go to the next step.
Go to the next step.
Repair or replace the malfunctioning part
according to electronic throttle control
system operation inspection results.
Go to the next step.
Low:
Inspect the fuel line for clogging.
If there is no malfunction, replace 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 fuel injector.
If fuel injector is normal, replace fuel
pump unit.
(See FUEL PUMP UNIT
REMOVAL/INSTALLATION [MZI-
3.7] .)
Go to the next step.