No.13 Knocking/Pinging - Mazda CX-7 2007 Workshop Manual

SYMPTOM TROUBLESHOOTING [L3 WITH TC]
NO.13 KNOCKING/PINGING[L3 WITH TC]
13 KNOCKING/PINGING
Sound is produced when air/fuel mixture is ignited by something other than a spark plug (e.g., hot spot in
DESCRIPTION
the combustion chamber).
• Poor fuel quality
• Engine overheating due to cooling system malfunction
• Variable swirl valve stuck closed
• Improper operation of electronic throttle system
• Air leakage or restriction from intake-air system
• ECT sensor or related circuit malfunction
• MAF sensor or related circuit malfunction
• IAT sensor No.1 or related circuit malfunction
• IAT sensor No.2 or related circuit malfunction
• Incorrect fuel injection timing or amount
• Fuel injector malfunction
• Knock sensor or related circuit malfunction
• Ignition system malfunction
• Erratic signal from CMP sensor
• Inadequate engine compression
• Inadequate fuel pressure (high-pressure side)
• Manifold absolute pressure (MAP) sensor or related malfunction
• Wastegate valve malfunction (stuck closed)
• Charge air cooler malfunction
• Fuel pressure sensor or related circuit malfunction
• Accelerator position sensor or related circuit malfunction
POSSIBLE CAUSE
• Suction control valve malfunction (built-in high pressure fuel pump)
• Exhaust system and/or three-way catalytic converter (TWC) restriction
• EGR system malfunction
Warning
The following troubleshooting flow chart contains the fuel system diagnosis and repair
procedures. Read the following warnings before performing the fuel system services:
• Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always
• Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or
Caution
• Disconnecting/connecting the quick release connector without cleaning it may possibly
01-03–50
keep sparks and flames away from fuel.
death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete
"BEFORE REPAIR ROCEDURE" and "AFTER REPAIR PROCEDURE" described in this
manual.
(See01-14-4 BEFORE REPAIR PROCEDURE[L3 WITH TC].)
(See01-14-4 AFTER REPAIR PROCEDURE[L3 WITH TC].)
cause damage to the fuel pipe and quick release connector. Always clean the quick release
connector joint area before disconnecting/connecting, and make sure that it is free of
foreign material.
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