Mazda MX-6 1998, Workshop Manual

Page: 201 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
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Idle Air Control Valve Inspection
1. Start the engine and run at idle.
2. Disconnect the IAC valve connector and verify if
the engine speed drops or engine stalls.
3. If engine speed does not drop or does not stall,
check following.
• IAC valve. (Refer to 0 1 -1 3A IDLE AIR
CONTROL VALVE INSPECTION [FS].)
• IAC valve air passage.
• Open or short circuit between IAC valve and
PCM.
4. Warm up the engine to normal operating
temperature and run it at idle.
5. Turn the electrical loads ON and verify the engine
speed is within the specification.
Load condition
Idle speed
MTX ATX
No load 550— 850
500— 800
A/C ON
625— 925 500— 800
P/S O N *1
550— 850 500— 800
E/L ON*2 625— 925
525— 825
*1 : Steering wheel fully turned.
*2 : When two or more of the following electrical loads are
met, but only one of the condition’s idle speed is the
same as a no-load condition.
• Headlight
• Cooling fan
• Blower motor
• A/C switch and fan switch ON
Note
• Excludes temporary idle speed drop
immediately after the electrical loads are
turned ON.
6. If not as specified, check the related switches and
wiring harnesses.
Fuel Pressure Hold Inspection
Warning
• 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 the “BEFORE REPAIR
PROCEDURE” and “AFTER REPAIR
PROCEDURE”. (Refer to 01-14 BEFORE
REPAIR PROCEDURE, 01-14 AFTER
REPAIR PROCEDURE.)
1. Disconnect the negative battery cable.
2. Install a fuel pressure gauge between the fuel filter
and the main fuel hose. (Install clamps as shown.)
3. Disconnect the negative battery cable.
4. Remove the fuel pump relay
Caution
•
Connecting the wrong fuel pump relay
socket terminals may possibly cause a
malfunction. Carefully connect the
specified terminals only.
5. Connect fuel pump relay socket terminal 30 and
87 by using a jumper wire.
IN S TA LL C LA M P S
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0 1 -0 1 A -1 7 3