8
Attempt to start engine at part throttle.
Does engine run smoothly at part
throttle?
Yes
operation.
(See
ENGINE CONTROL SYSTEM
OPERATION INSPECTION [MZI-3.7]
.)
No
Go to the next step.
9
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
position.
Is fuel line pressure correct with ignition
switch ON?
(See
FUEL LINE PRESSURE
INSPECTION [MZI-3.7]
.)
Yes
Go to the next step.
No
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]
.)
10
Is the fuel line pressure held after ignition
switch is turned off?
(See
FUEL LINE PRESSURE
INSPECTION [MZI-3.7]
.)
Yes
Go to the next step.
No
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]
.)
11
Disconnect a vacuum hose from purge
solenoid valve and plug opening end of
vacuum hose.
Start engine.
Is starting condition improved?
Yes
Inspect if the purge solenoid valve is stuck
open.
No
Go to the next step.
12
Inspect the MAF sensor for following:
z
Contamination
z
MAF sensor terminal B voltage
(GND circuit)
Is there any contamination?
Yes
Repair or replace the malfunctioning part.
No
Go to the next step.
13
Visually inspect the exhaust system part.
Is there any deformed exhaust system
part?
Yes
Replace the suspected part.
No
Go to the next step.
Inspect the starting system.
Yes
Inspect for loose connectors or poor
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
Microsoft
Sunday, November 15, 2009 10:10:04 AM
Page 24
© 2005 Mitchell Repair Information Company, LLC.
