Mazda 626 Station Wagon, Workshop Manual

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TROUBLESHOOTING
STEP INSPECTION RESULTS
ACTION
12 Visually inspect for fuel leakage at fuel injector
O-ring and fuel line. Service as necessary.
Does fuel line pressure hold after ignition switch
is turned off?
Fuel line pressure
More than 150 kPa {1.5 kgf/cm2, 21 psi} for 5
min.
Yes Go to next step.
No Inspect pressure regulator diaphragm condition.
If condition is okay, inspect fuel injector.
If condition is not okay, replace pressure
regulator.
13 Install vacuum gauge to intake manifold.
Start engine.
Does fuel pressure gauge reading increase as
vacuum gauge reading decreases and/or does
fuel pressure gauge reading decrease as
vacuum reading increases?
Yes
Go to next step.
No Connect vacuum pump to pressure regulator.
Start engine. Verify that fuel pressure gauge
reading changes as vacuum changes.
If changes, inspect vacuum line.
If does not change, replace pressure regulator.
14 Note
• The following test is for engine stalling with
A/C on. If other symptoms exist, go to next
step.
Connect a pressure gauge to A/C low and high
pressure side lines.
Turn A/C on and measure low side and high
side pressures.
Are pressures 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
15
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.
16 Visually inspect CMP sensor and tooth of
camshaft.
Are CMP sensor and tooth of camshaft okay?
Yes Go to next step.
No Replace malfunctioning parts.
17
Inspect EGR system.
(See Section F1-152 EGR Control Inspection)
Is EGR system okay?
Yes Go to next step.
No Replace malfunctioning parts.
18 Is engine compression correct? Yes Inspect following:
• Valve timing
• Automatic transaxle (ATX)
• Clutch (MTX)
No Inspect for cause.
19 Verify test results. If okay, return to diagnostic index to service any additional symptoms.
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