Mazda 3 Workshop Manual page 473

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
Measure gap between the CKP sensor
and teeth of crankshaft pulley.
Specification
9
0.5-1.5 mm {0.02-0.05 in}
Is gap within specification?
Inspect the ignition coil related wiring
harness condition (intermittent open or
10
short circuit) for all cylinders.
Are wiring harness conditions normal?
Inspect the spark plug condition.
11
Is the spark plug wet, covered with
carbon or grayish white?
Start the engine and disconnect the
IAC valve connector.
12
Does engine speed drop or the engine
stall?
Install fuel pressure gauge between
the fuel pipe and the fuel distributor.
Start the engine and idle it.
Measure fuel line pressure during idle.
13
Is fuel line pressure correct during
idle?
(See FUEL LINE PRESSURE
INSPECTION.)
Visually inspect the fuel injector, O-
ring, and fuel line for fuel leakage.
14
Service if necessary.
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Go to the next step.
Replace the crankshaft pulley.
Go to the next step.
Repair the wiring harnesses.
Spark plug is wet or covered with carbon:
Inspect for fuel leakage from the fuel injector.
Spark plug is grayish white:
Inspect for clogged the fuel injector.
Install spark plugs on original cylinders.
Go to the next step.
Go to the next step.
Inspect the IAC valve and wiring harness.
(See IDLE AIR CONTROL (IAC) VALVE
INSPECTION [Z6].)
Go to the next step.
Low:
Inspect the fuel line for clogging.
• If there is no malfunction, replace fuel pump
unit.
(See FUEL PUMP UNIT
REMOVAL/INSTALLATION.)
High:
Replace the fuel pump unit.
(See FUEL PUMP UNIT
REMOVAL/INSTALLATION.)
Go to the next step.
Inspect the pressure regulator diaphragm
condition.
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