Mazda CX-9 Grand Touring 2009 Manual page 1315

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
Attempt to start engine at part throttle.
8 Does engine run smoothly at part
throttle?
Install the fuel pressure gauge between
the fuel pipe and fuel distributor.
Short check connector terminal F/P to
body GND using a jumper wiring.
Turn the ignition switch to the ON
9
position.
Is fuel line pressure correct with ignition
switch ON?
(See FUEL LINE PRESSURE
INSPECTION [MZI-3.7] .)
Is the fuel line pressure held after ignition
switch is turned off?
10
(See FUEL LINE PRESSURE
INSPECTION [MZI-3.7] .)
Disconnect a vacuum hose from purge
solenoid valve and plug opening end of
11 vacuum hose.
Start engine.
Is starting condition improved?
Inspect the MAF sensor for following:
Contamination
MAF sensor terminal B voltage
12
(GND circuit)
Is there any contamination?
Visually inspect the exhaust system part.
13 Is there any deformed exhaust system
part?
Inspect the starting system.
2008 Mazda CX-9 Grand Touring
operation.
Yes (See ENGINE CONTROL SYSTEM
OPERATION INSPECTION [MZI-3.7].)
No
Yes Go to the next step.
No
Yes Go to the next step.
No
Inspect if the purge solenoid valve is stuck
Yes
open.
No
Yes Repair or replace the malfunctioning part.
No
Yes Replace the suspected part.
No
Yes
Inspect for loose connectors or poor
Go to the next step.
Zero or low:
Inspect the fuel pump relay and the 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] .)
Inspect the fuel injector.
(See FUEL INJECTOR INSPECTION
[MZI-3.7] .)
If the fuel injector is normal, replace the fuel
pump unit.
(See FUEL PUMP UNIT
REMOVAL/INSTALLATION [MZI-
3.7] .)
Go to the next step.
Go to the next step.
Go to the next step.