Mazda 6 2002, Workshop Manual

Page: 327 / 1248

TROUBLESHOOTING
F–197
F
14 Will engine start and run smoothly at part
throttle? Yes Inspect IAC valve and wiring harness.
No Go to next step.
15 Connect WDS or equivalent to DLC-2.
Access RPM PID.
Is RPM PID indicating engine speed when
cranking engine? Yes Go to next step.
No Inspect for following:
•
Open or short circuit in CKP sensor
•
Open or short circuit between CKP sensor and
PCM terminal 1A or 1B
•
Open or short circuit in CKP sensor harnesses
If CKP sensor and harness are okay, go to next step.
16 Visually inspect CKP sensor and teeth of
crankshaft pulley.
Are CKP sensor and teeth of crankshaft pulley
okay? Yes Go to next step.
No Replace malfunctioning parts.
17 Measure gap between CKP sensor and teeth of
crankshaft pulley.
Specification
0.5—1.9 mm {0.020—0.075 in}
Is gap within specification?
Yes Go to next step.
No Adjust CKP sensor.
18 Inspect for cranks on high-tension leads.
Is there any crank on high-tension leads? Yes Repair suspected high-tension leads.
No Go to next step.
19 Is strong blue spark visible at each disconnected
high-tension lead while cranking engine? Yes Go to next step.
No Inspect for following:
•
Open or short circuit in ignition coil
•
Open circuit in high-tension leads
•
Open circuit between ignition coil connector GND
terminal and GND
•
Open circuit between ignition switch and ignition
coil
•
Open circuit between ignition coil and PCM
terminal 1A or 1B
20 Inspect spark plug conditions.
Is spark plug wet, covered with carbon or
grayish white? Yes Spark plug is wet or covered with carbon:
Inspect for fuel leakage from injector.
Spark plug is grayish white:
Inspect for clogged fuel injector.
No Install spark plugs on original cylinders.
Go to next step.
21 Remove and shake PCV valve.
Does PCV valve rattle? Yes Go to next step.
No Replace PCV valve.
22 Inspect for restriction in exhaust system. Yes Inspect exhaust system.
No Go to next step.
23 Install fuel pressure gauge between fuel pipe
and fuel distributor.
Connect a jumper wire between F/P terminal at
DLC-2 in engine compartment and GND.
Turn ignition switch to ON position.
Is fuel line pressure correct when ignition switch
is turned on/off
five times ?
(See F–20 FUEL LINE PRESSURE
INSPECTION )
Yes Go to next step.
No Zero or low:
Inspect for clogged fuel line.
If okay, replace fuel pump unit.
High:
Replace fuel pump unit.
24 Visually inspect for fuel leakage at fuel injector
O-ring and fuel line.
Service as necessary.
Is fuel line pressure held after ignition switch is
turned off?
(See
F–20 FUEL LINE PRESSURE
INSPECTION )
Yes Go to next step.
No Inspect fuel injector.
If fuel injector is okay, replace fuel pump unit.
25 Disconnect vacuum hose between purge
solenoid valve and intake manifold from purge
solenoid valve side.
Plug opening end of vacuum hose.
Attempt to start engine.
Is starting condition improved? Yes Inspect if purge solenoid valve sticks open
mechanically.
Inspect evaporative emission control system.
No Go to next step.
STEP INSPECTION RESULTS ACTION