DIAGNOSTIC PROCEDURE
DIAGNOSTIC PROCEDURE
POSSIBLE CAUSE
Black smoke (Rich fuel mixture):
z
Air cleaner restriction
z
Intake-air system is collapsed or restricted.
z
Fuel return line is restricted.
z
Excessive fuel pressure
z
Improper engine compression
z
Injector fuel leakage
z
Ignition system malfunction
WARNING:
The following troubleshooting flow chart contains fuel system diagnosis
and repair procedures. Read following warnings before servicing fuel
system:
z
Fuel vapor is hazardous. It can easily ignite, causing serious injury
and damage. Always keep sparks and flames away from fuel.
z
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 REPAIR
PROCEDURE" and "AFTER REPAIR PROCEDURE" described in
this manual.
(see BEFORE REPAIR PROCEDURE [MZI-3.5] .)
(see AFTER REPAIR PROCEDURE [MZI-3.5] .)
CAUTION:
z
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
What color is smoke coming from the
exhaust system?
Blue
Burning oil is indicated.
Go to the next step.
White
Water in combustion is indicated.
Go to Step 3.
Black
Rich fuel mixture is indicated.
Go to Step 4.
2007 Mazda CX-9 Grand Touring
2007 ENGINE PERFORMANCE Symptom Troubleshooting (MZI-3.5) - CX-9
Microsoft
Sunday, November 15, 2009 9:27:37 AM
Page 72
© 2005 Mitchell Repair Information Company, LLC.