1987 MAZDA 626 ignition

4A
IDLE
SPEED AND
IDLE
MIXTURE
76G04A-059
76G04A-060
76G04A-061

IDLE
SPEED AND IDLE MIXTURE
ADJUSTMENT
Note
a) Before adjusting the idle speed and idle
mixture, be sure the ignition timing, spark
plugs, carburetor float level, etc., are all in
normal operation condition.
b)Turn off all electrical loads.
c) This adjustment must be done while the fan
motor is not operating.
Idle Speed
1. Connect a tachometer to the engine.
2. Warm up the engine, and check that the choke
valve has fully opened.
3. Check the idle speed.
Specification
MTX ATX (in N range)
Specification Others
FE 8Valve Unleaded fuel F6 F8 & FE
Idle speed rpm 800 +6S 850 +5S 950 +5o° 900 +5§
4. If not within specification, adjust the idle speed by
turning the throttle adjust screw.
Caution
After adjusting the idle speed, the dashpot ad-
justment should be checked and adjusted if
necessary.
Idle Mixture
[Except FE 8Valve—Unleaded Fuel]
Adjust the idle mixture as follows, after adjusting the
idle speed.
1. Disconnect the secondary air hoses from the reed
valves and plug them. (If equipped.)
2. Insert an exhaust gas analyzer into the tail pipe and
measure the CO concentration.
CO concentration: 2.0 ± 0.5%
3. If not within the specification, remove the blind cap
from the mixture adjust screw.
76G04A-062
4A—38

AUTO-RETURN CHOKE SYSTEM 4A
Choke Magnet
1. Remove the under dash cover.
2. Disconnect the choke magnet connector.
3. Turn the ignition switch on and check the resistance
using an ohmmeter.
Resistance: Approx. 3512
4. If it is not within the specification, the choke mag-
net is malfunction.
76G04A-069
76G04A-070
Water thermo switch
1. Remove the switch from the intake manifold.
2. Place the switch in a container of water with a ther-
mometer.
3. Connect an ohmmeter to the switch.
4. Heat the water slowly and check that the switch
has continuity at 67°C (152°F).
5. Replace if necessary.
Note
a) Apply sealing tape to the threads of the
switch.
b) After installing, check the coolant level and
check for leaks.
4A—41

4 A DECELERATION CONTROL SYSTEM
BYPASS AIR CONTROL SYSTEM
FE and F8 [Except General and Middle East]
E -tr Air bypass solenoid valve
I
Engine
control
unit
FE 8 Valve — Unleaded fuel

J
f^^n
Ignition coil
Idle switch
76G04A-084
The bypass air control system consists of the bypass solenoid valve, idle switch, ignition coil, and en-
gine control unit.
This system opens the bypass air passage to the intake manifold during deceleration above ap'prox.
2,300 rpm (ECE, Hong Kong, and Singapore), or above approx. 3,500 rpm (FE 8 Valve—Unleaded
fuel).
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting. (Refer to page 4A—46 or 47.)
Troubleshooting
Possible cause System inspection Air bypass solenoid valve
Page 4A-48 4A-49
Checking order 1 2
/
/o fcl i /o ' jXj^/* J
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/ Terminal AGL...Leaded Fuel
L LB...FE 8 Valve—Unleaded Fuel
System Inspection
1. Warm up the engine and run it at idle.
2. Connect a tachometer.
3. Disconnect the bypass air hose from the air cleaner
and place a finger over the hose opening.
76G04A-085
4A—48

DECELERATION CONTROL SYSTEM 4 A
SLOW FUEL CUT SYSTEM [FE 8VALVE—UNLEADED FUEL]
76G04A-096
This system shuts the primary slow fuel passage to prevent run-on and overheating of the exhaust
system when the ignition switch is turned OFF or during deceleration (engine speed above 2,300
rpm and idle switch ON). The slow fuel cut solenoid is actuated by the engine control unit and ignition
switch.
Troubleshooting
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting Guide. (Refer to page 4A—47.)
Possible cause System inspection Slow fuel cut solenoid valve
Page 4A—53 4A—34
Check order 1 2
System Inspection
1. Warm up the engine and run it at idle.
2. Connect a tachometer to the engine.
3. Connect a voltmeter to the carburetor connector
terminal (BW wire).
4. Increase the engine speed to 4,000 rpm; then re-
lease the throttle lever.
5. Measure the terminal voltage.
Engine speed Voltage
Above approx. 2,300 rpm Approx. 12V
Below approx. 2,300 rpm Below 1.5V
76G04A-097
4A-53

4 A DECELERATION CONTROL SYSTEM
COAST ENRICHMENT SYSTEM [FE 8VALVE—UNLEADED FUEL]
Ignition coil
Engine
control
unit
Coast enrichment
solenoid valve
Richer air bleeds
Secondary main
air bleed
Idle switch
© e
To secondary
main jet
76G04A-098
This system opens the fuel passage to the secondary stage of the carburetor during deceleration at
engine speeds of 2,300—1,500 rpm. The coast enrichment solenoid valve is actuated by the engine
control unit.
Troubleshooting
Possible cause System Inspection Coast enrichment solenoid valve
Engine control unit terminal Possible cause System Inspection Coast enrichment solenoid valve
A B D 1
Page 4A—54 4A—55 4A—91
Checking order 1 3 2
System Inspection
1. Warm up the engine to the normal operating tem-
perature and run it at idle.
2. Connect a voltmeter to the carburetor connector
terminal E.
3. Connect a tachometer to the engine.
76G04A-099
4A—54

4A DECELERATION CONTROL SYSTEM
COASTING LEANER SYSTEM (F6 SINGAPORE MTX)
Coasting leaner
0 oAir
a n, © © Battery Ignition
switch Secondary
throttle valve
| / Relay
Engine control unit
Ignition coil
76G04A-102
This system consists of the coasting leaner solenoid valve, engine control unit, ignition coil, and idle switch.
When the idle switch is ON and the engine speed is more than approx. 2,100 rpm (deceleration),
the coasting leaner solenoid valve opens the air passage port to prevent afterburn in the exhaust system.
Troubleshooting
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting. (Refer to page 4A—47)
Possible cause System inspection Coasting leaner solenoid valve Relay
Page 4A—56 4A—57 4A—57
Checking order 1 2 3
Coasting leaner System Inspection
1. Warm up the engine and run it at idle.
2. Connect a tachometer to the engine.
3. Connect a voltmeter to the coasting leaner sole-
noid valve connector (LgB wire).
76G04A-103
4A—56

IDLE-UP CONTROL SYSTEM 4A
Troubleshooting
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting. (Refer to page 4A—70.)
\\ Possible cause
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Symptom
Section
15 Section 15 4A—95 4A—93 Section
15 4A—77 4A—86— 4A—91 4A—77
Checking order 3 4 5 6 7 8 2 9 1
76G04A-152
'Engine control unit terminal Check the following terminal voltages
Transmission Terminal
MTX A, C, D, H, Q, R
ATX I, 2B, 2C, 2D, 2E, 2H, 2M
System Inspection
1. Warm up the engine and run it at idle.
2. Connect a jumper wire to the carburetor connec-
tor terminal wire (YW) and ground.
3. Connect a tachometer to the engine.
4. Turn all accessories off.
5. Verify that the engine speed is within specification.
Engine speed: 900—950 rpm (MTX)
Engine speed: 1,000—1,050 rpm
(ATX; in N range)
6. Disconnect the tachometer.
76G04A-153
Idle-up Solenoid Valve
1. Turn all accessories OFF and turn the ignition
switch ON.
2. Disconnect the idle-up solenoid valve connector.
3. Ground the carburetor connector terminal wire
(YW) using with a jumper wire.
4. Check the rod is drawn into the valve.
5. Replace if necessary.
U
76G04A-154
4A-77

4 A IGNITION TIMING CONTROL SYSTEM
IGNITION TIMING CONTROL SYSTEM
F8 and FE (12-VALVE)—ATX (ECE, Singapore, and Hong Kong)
Ignition coil
76G04A-160
This system consists of the distributor, solenoid valve, and several switches, vacuum to the vacuum
control unit of the distributor is cut when the conditions below are met.
Item Condition
Engine speed Below 2,300 rpm
Selector lever position Other than P and N range
Coolant temperature Engine coolant: below 72°C (162°F) Radiator coolant: above 17°C (65°F)
4A—80