Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL KL]
11
LACK/LOSS OF POWER - ACCELERATION/CRUISE
DESCRIPTION
Performance poor under load (i.e., power down when climbing hills)
POSSIBLE
CAUSE
• Improper A/C system operation
• Air leak from intake air system parts
• EGR valve malfunction
• Erratic signal from crankshaft position sensor
• Vacuum leaks
• Spark leak from hightension leads
• PCV valve malfunction
• Restriction in exhaust system
• Inadequate fuel pressure
• Fuel leak from injector
• Intermittent open or short of mass air flow sensor, throttle position sensor and vehicle speed sensor
• Automatic transaxle malfunction
• Improper VRIS operations
• Erratic signal or no signal from camshaft position sensor
• Purge solenoid valve malfunction
• Brake dragging
• Low engine compression
• Poor fuel quality
• Air cleaner restriction
• Improper valve timing due to timing belt jump
• Intermittent open/short in fuel pump circuit
• Fuel pump mechanical malfunction
• Fuel injector clogged
• Clutch slippage
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 leaks 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.
r r 0 1 -1 4 BEFORE REPAIR PROCEDURE
o - 0 1 -1 4 AFTER REPAIR PROCEDURE
STEP INSPECTION
ACTION
1 Verify following:
• Vacuum connection.
• Air cleaner element.
• No air leaks 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 control.
• Fuel quality:
• Proper octane, contamination,
winter/summer blend.
Are all items okay?
Yes Go to next step.
No Service as necessary and repeat step 1.
2 Retrieve and record any continuous memory,
KOEO and KOER DTCs.
If engine stall condition exists, retrieve
continuos memory and KOEO DTCs.
Are there any DTCs displayed?
Yes
Go to appropriate DTC test.
No Go to next step.
3 Verify DTC of traction control system.
Is diagnostic trouble code displayed?
Yes Go to traction control diagnosis.
d
- 04-01 ANTILOCK BRAKE SYSTEM AND
TRACTION CONTROL SYSTEM ON-BOARD
DIAGNOSIS
No Go to next step.
4
Is engine overheating? Yes
Go to flowchart 17 for “COOLING SYSTEM CONCERNS
OVERHEATING”.
No Go to next step.
0 1 -0 1 B -1 51