Mazda 6 2002, Workshop Manual

Page: 337 / 1248

TROUBLESHOOTING
F–207
F
NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE
A6E398018881W14
Diagnostic procedure
12 LACK/LOSS OF POWER — ACCELERATION/CRUISE
DESCRIPTION Performance is poor under load (e.g., power down when climbing hills).
POSSIBLE CAUSE
•
Improper A/C system operation
•
Erratic signal or no signal from CMP sensor
•
Air leakage from intake-air system parts
•
Improper VIS operation (if equipped)
•
Improper VTCS operation
•
Purge control solenoid malfunction
•
EGR valve malfunction
•
Brake dragging
•
Erratic signal from CKP sensor
•
Low engine compression
•
Vacuum leakage
•
Poor fuel quality
•
Spark leakage from high-tension leads
•
Engine overheating
•
Throttle body malfunction
•
Spark plug malfunction
•
Air cleaner restriction
•
PCV valve malfunction
•
Improper valve timing due to jumping out of timing belt
•
Improper variable valve timing control operation (if equipped)
•
Restriction in exhaust system
•
Intermittent open or short in fuel pump related circuit
•
Inadequate fuel pressure
•
Fuel pump mechanical malfunction
•
Fuel line restriction or clogging
•
Fuel leakage from fuel injector
•
Fuel injector clogging
•
Intermittent open or short of MAF sensor, TP sensor and VSS
•
ATX malfunction (ATX)
•
Clutch slippage (MTX)
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
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" described in this
manual.
(See
F–17 BEFORE REPAIR PROCEDURE .)
(See F–17 AFTER REPAIR PROCEDURE .)
Caution
•
Disconnecting/connecting quick release connector without cleaning it may possibly cause
damage to fuel pipe and quick release connector. Always clean quick release connector
joint area before disconnecting/connecting, and make sure that it is free of foreign material.
STEP INSPECTION RESULTS ACTION
1 Verify following:
•
Vacuum connection
•
Air cleaner element
•
No air leakage from intake-air system
•
No restriction of intake-air system
•
Proper sealing of intake manifold and
components attached to intake manifold;
such as EGR valve, IAC valve
•
Fuel quality (e.g. proper octane,
contamination, winter/summer blend)
Are all items okay?
Yes Go to next step.
No Service as necessary.
Repeat Step 1.