Mazda 626 Station Wagon, Workshop Manual

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TROUBLESHOOTING
STEP INSPECTION RESULTS ACTION
12
Note
• Following test is for engine stalling with A/C
on concern. If other symptoms exist, go to
next step.
Connect pressure gauge to A/C low and high
side pressure lines.
Turn A/C on and measure low side and high
side pressures.
Are the pressure within specifications?
(See Section U)
Yes Go to next step.
No If A/C is always on, go to symptom
troubleshooting No.23 “A/C is always ON or A/C
compressor runs continuously”.
For other symptoms, inspect following:
• Refrigerant charging amount
• Condenser fan operation
13
Inspect for A/C cut-off operation.
Does A/C cut-off work properly? Yes
Go to next step.
No Inspect A/C cut-off system components.
14 Disconnect vacuum hose between purge
solenoid valve and intake manifold from purge
solenoid valve side.
Plug opening end of vacuum hose.
Drive vehicle.
Does engine condition improve?
Yes Inspect if purge solenoid valve is stuck open
mechanically.
Inspect evaporative emission control system.
No Go to next step.
15 Visually inspect CMP sensor and teeth of
camshaft.
Are CMP sensor and teeth of camshaft okay? Yes Go to next step.
No Replace malfunctioning parts.
16 Inspect EGR system.
(See F1-152 EGR Control Inspection)
Is EGR system okay? Yes Go to next step.
No
Replace malfunctioning parts.
17 Is engine compression correct? Yes Inspect following:
• Valve timing
• Automatic transaxle (ATX)
• Clutch (MTX)
• Brake system for dragging
No Inspect for cause.
18 Verify test results. If okay, return to diagnostic index to service any additional symptoms.
N0.12 KNOCKING/PINGING - ACCELERATION/CRUISE
12 Knocking/pinging - acceleration/cruise
DESCRIPTION
• Sound is produced when air/fuel mixture is ignited by something other than spark plug (e.g., hot spot
in combustion chamber).
POSSIBLE
CAUSE
• Engine overheating due to cooling system malfunction
• Inadequate engine compression
• Inadequate fuel pressure
• Knock sensor and related circuit malfunction
Warning
• Following troubleshooting flow chart contains fuel system diagnosis and repair
procedures. Read following warnings before performing fuel system service:
— Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage.
Always keep sparks and flames away from fuel.
— 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”. (See
Section F)
Caution
• Disconnecting/connecting the quick release connector without cleaning it may possibly
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.
F1-127