Mazda 626 Station Wagon, Workshop Manual, Page: 44 / 577

ENGINE TUNE-UP
6. Disconnect the SST or a jumper wire.
7. Disconnect the dwell tachometer.
IDLE SPEED INSPECTION
Except for GF4A-EL Models
Using the SSTs (NGS tester)
1. Perform “ENGINE TUNE-UP PREPARATION”.
2. Verify that the idle speed is normal. (See F1 -22
IDLE SPEED ADJUSTMENT.)
3. Verify that the RPM PID is within the specification
using the SSTs (NGS tester).
• If not as specified with all load conditions,
inspect the IAC valve.
• If not as specified with some load condition,
inspect the related input switches, harnesses,
and connectors.
Specification
Load condition
ldle-up speed (rpm) *1
P, N position D range
No load
E/LON*2
600— 700
P/S operating *3
(650 ±50)
A/CON*4
*1 : Excludes temporary idle speed drop just after the
electrical loads (E/L) are turned on.
*2 : Headlight is on, blower control switch is above 1 st,
cooling fan is operating, rear window defroster is on.
*3 : Steering wheel is fully turned.
•*: A/C switch and blower control switch are on.
Not using the SSTs (NGS tester)
1. Perform “ENGINE TUNE-UP PREPARATION”.
2. Verify that the idle speed is normal. (See F1 -22
IDLE SPEED ADJUSTMENT.)
3. Verify that idle speed is within the specification
using the dwell tachometer.
• If not as specified with all load conditions,
inspect the IAC valve.
• If not as specified with some load condition,
inspect the related input switches, harnesses,
and connectors.
Specification
Load condition
ldle-up speed (rpm) *1
P, N position
Range D
No load
E/LON*2
600—700
P/S operating *3
(650 ±50)
A/CON*4
*1: Excludes temporary idle speed drop just after the
electrical loads (E/L) are turned on.
*2 : Headlight is on, fan switch is above 1st, cooling fan is
operating, rear window defroster is on.
13 : Steering wheel is fully turned.
**: A/C switch and fan switch are on.
IDLE MIXTURE INSPECTION
Except for GF4A-EL Models
1. Perform “ENGINE TUNE-UP PREPARATION”.
2. Verify that the idle speed and ignition timing are
within the specification. (See F1-21 IGNITION
TIMING INSPECTION.)
3. Warm up the engine by holding the engine speed
at 2500 — 3000 rpm for approx. 3 minutes.
4. Insert an exhaust gas analyzer to the tailpipe.
5. Verify that the CO and HC concentrations are
within the regulation.
• If not within the regulation, inspect the
following:
— On-board diagnostic (See F1-30
ON-BOARD DIAGNOSTIC TEST)
— H02S (See Section F.)
— Intake manifold vacuum (See Section F.)
— Fuel line pressure (See Section F.)
— Ignition timing control (See F1-21
IGNITION TIMING INSPECTION.)
• If the systems and devices are normal,
replace the TWC.
F1-23