engine MAZDA 626 1987 Workshop Manual

4 A FUEL SYSTEM
76G04A-044
76G04A-045
76G04A-046
Choke Breaker Diaphragm
1. Warm up the engine to the normal operating tem-
perature, then stop the engine.
2. Set the choke valve to the fully closed position.
3. Apply 400 mmHg (15.7 inHg) vacuum to the di-
aphragm.
4. Measure the clearance between the choke valve
and air horn with a wire gauge.
Cl68r8ncG'
2.45—3.11 mm (0.096—0.122) FE, F8
1.68—2.14 mm (0.066—0.084 in) F6
5. If not within specification, adjust by bending the
lever.
Choke Opener
ECE, Hong Kong, Singapore, and Middle East
1. Warm up the engine to the normal operating tem-
perature, then stop the engine.
2. Set the choke valve to the fully closed position.
3. Apply 400 mmHg (15.7 InHg) vacuum to the di-
aphragm.
4. Measure the clearance between the choke valve
and air horn with a wire gauge.
Specification Clearance mm (in)
ECE, Hong Kong, and Singapore
(Except F6 MTX) 3.7—4.0 (0.15—0.16)
Middle East 3.3—3.6 (0.13—0.14)
F6 Singapore MTX 3.2—3.5 (0.13—0.14)
5. If not within specification, adjust by bending the
connecting rod.
76G04A-047
4A-34

FUEL SYSTEM 4 A
76G04A-048
76G04A-049
FUEL PUMP
Inspection
Fuel pressure
1. Disconnect the hose at the carburetor and connect
a fuel pressure gauge.
2. Disconnect the fuel return hose from the fuel pump
and plug the fuel pump return pipe as shown in
the figure,
3. Measure the pressure while the engine is idling.
Replace the pump, if necessary.
FE & F8 (ECE,
Hong Kong,
Singapore)
Others
Pressure kPa
(kg/cm2, psi)
20—29 (0.2-0.3, 2.8-4.3)
20-26
(0.20-0.27,
2.8-3.8)
Flow rate (volume)
1. Disconnect the carburetor fuel hose and insert the
end into a measuring breaker.
2. Disconnect the fuel return hose from the fuel pump
and plug the fuel pump return pipe as shown in
the figure.
3. Start the engine and measure the amount of fuel
pumped per minute.
Volume: More than 860 cc (52.5 cuin)/min
Removal
1. Remove in the following order.
(1) Fuel outlet hose
(2) Fuel inlet hose
(3) Fuel return hose
(4) Fuel pump
(5) Gasket
(6) Insulator
(7) Gasket
76G04A-050
Installation
Install in the reverse order of removal.
Caution
a) Replace the gasket whenever the fuel pump
is replaced.
b) Be sure to connect the hoses in the correct
positions.
Check for leaks.
76G04A-051
4A—35
expert22 fl/i* http://rutracker.org

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

IDLE SPEED AND IDLE MIXTURE 4A
76G04A-063
76G04A-064
4. Turn the mixture adjust screw to adjust the CO con-
centration.
5. Recheck the idle speed.
6. Fit a new blind cap onto the mixture adjust screw.
Idle Mixture [FE 8Valve—Unleaded Fuel]
Adjustment of the idle mixture is normally un-
necessary.
But if it is necessary, adjust it as follows.
Note
Do not insert the exhaust gas analyzer into the
tail pipe.
Before adjust the idle mixture, check and set
the idle speed.
1. Disconnect the secondary air hoses.
2. Insert an exhaust gas analyzer into the hose and
plug it to prevent leakage.
3. Start the engine and run it at idle.
4. Measure the CO concentration.
5. Remove the blink cap from the mixture adjust
screw.
6. Turn the mixture adjust screw and adjust the CO
level.
CO concentration: 2.0 ± 0.5%
7. If the idle speed fails to meet specification as the
result of the above steps, adjust the idle.
8. Reconnect the secondary air hoses.
9. Fit a new blind cap onto the mixture adjust screw.
76G04A-065
4A-39

4 A AUTO-RETURN CHOKE SYSTEM
AUTO-RETURN CHOKE SYSTEM
[FE 8VALVE—UNLEADED FUEL, MIDDLE EAST, and F6—GENERAL]
r ~ I
76G04A-066
An auto-return choke is adopted to prevent the catalytic converter from over-heating because of over
use of the choke. This system opens the choke valve by causing the choke knob to return when the
engine coolant temperature is more than 67°C (153°F).
TROUBLESHOOTING
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting Guide. (Refer to pages 4A—16, 21, or 22)
Possible cause
" ^ Page
Symptom
System inspection Choke magnet Water thermo switch
Possible cause
" ^ Page
Symptom 4A—40 4A—41 4A—41
Checking order 1 2 3
76G04A-067
System Inspection
1. Make sure that the engine is cold and turn the ig-
nition switch ON.
2. Pull out the choke knob and check that it is held on.
3. Start the engine and check that the choke knob
returns during warming-up.
76G04A-068
4A—40

4A PTC HEATER SYSTEM
PTC HEATER SYSTEM
[FE
and
F8 engine (except Middle
East)]
76G04A-071
The PTC heater system consists of the PTC heater, relay, and water thermo switch. The system is
designed to prevent carburetor icing when the engine operating temperature is low t assure optimum
driveability.
TROUBLESHOOTING
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting Guide. (Refer to pages 4A—19, —20, or—22)
FE 8Valve—Unleaded Fuel
Possible cause System
inspection
Water thermo switch (intake manifold)
PTC heater
Water
thermo
switch
(Radiator)
PTC heater
relay
Page 4A—43 4A—41 4A—43 4A—95 4A—44
Checking order 1 2 3 4 5
Except FE 8Valve—Unleaded Fuel
Possible cause System inspection
Water thermo switch (Radiator)
PTC heater PTC heater
relay
Page 4A—43 4A—95 4A—43 4A—44
Checking order 1 2 3 4
76G04A-072
4A-42

PTC HEATER SYSTEM 4A
System Inspection
Except FE 8Valve—Unleaded Fuel
1. Connect a voltmeter to the PTC heater connector.
2. Start the engine and measure the voltage.
Specification
Radiator coolant
temperature Below 17°C (63°F) Above
17°C (63°F)
Voltage Approx. 12V ov
76G04A-073
FE 8Valve—Unleaded Fuel
1. Start the engine.
2. Connect a voltmeter to the PTC heater connector
terminals and measure the voltage.
Voltage
Engine coolant
temperature
Below 67°C (152°F)
Above 67°C (152°F)
Radiator coolant temperature Below 17°C (63°F) Above 17°C (63°F) —
Terminal BrB Approx.
12V
OV OV Terminal BrW
Approx.
12V Approx. 12V OV
76G04A-074
PTC Heater
Except FE 8Valve—Unleaded Fuel
1. Disconnect the PTC heater connector.
2. Check for continuity of the heater with an
ohmmeter.
76G04A-075
FE 8Valve—Unleaded Fuel
1. Disconnect the PTC heater connector.
2. Check for continuity between terminal wire (BrW)
and a ground.
3. Check for continuity between terminal wire (BrB)
and (B).
76G04A-076
4A—43

4 A DECELERATION CONTROL SYSTEM
TROUBLESHOOTING
Check the condition of the wiring harness and connectors before checking the engine control unit
or switches.
FE 12Valve and F8 (ECE, Hong Kong and Singapore)—MTX
Possible cause
Page
Symptom

Anti-afterburn

valve
Dashpot Bypass
air
control
system
Idle

switch
main
air

bleed

control
system

Engine

control

unit

terminal
Possible cause
Page
Symptom

Anti-afterburn

valve
Dashpot Bypass
air
control
system
Idle

switch
main
air

bleed

control
system
E L M
Possible cause
Page
Symptom 4A—50 4A—50 4A—48 4A—93 4A—51 4A—88
Runs rough on deceleration 2 1 3 5 4
Afterburn in exhaust system 1 2 4 3 5 6
Poor fuel consumption 1 2 3
Fails emission test 7 6 1 2 3 4 5
High idle speed after warm up 1 2 3
Engine stalls during warm up 1
Rough idle during warm up 1
Poor acceleration, hesitation, or lack of power 1
76G04A-079
FE 12Valve and F8 (ECE, Hong Kong and Singapore)—ATX
Possible cause o> o 4-* uT u. E 3
(0 >
c k_ 3 •Q L-
2 ST c
o o "O at 0)
_>. c O
£ O
o w c o
• 1
\Page a •
C
3 i CO V S.
v>

5 E c ® 5 »
5 w a> in m
< BO M S «T 2 B D 2N
Symptom 4A—50 4A—48 4A—51 4A—93 4A—86
Runs rough on deceleration 2 3 1 5 4
Afterburn in exhaust system 1 2 3 4 5
Poor fuel consumption 1 2
Fails emission test 7 6 2 1 3 4 5
High idle speed after warm up 1 2
Engine stall during warm up 1
Rough idle during warm up 1
Poor acceleration, hesitation, or lack of power 1
76G04A-080
4A—46

DECELERATION CONTROL SYSTEM 4 A
FE 8Valve—Unleaded Fuel
Possible cause
\Page ^s^
Symptom

Slow

fuel
cut
system
Coast
enrichment
system
Idle

switch
Anti-afterburn
valve

Bypass

air
control

system
Dashpot
(only
MTX)
Engine
control
unit

terminal

Possible cause
\Page ^s^
Symptom

Slow

fuel
cut
system
Coast
enrichment
system
Idle

switch
Anti-afterburn
valve

Bypass

air
control

system
Dashpot
(only
MTX)
A C G I
Possible cause
\Page ^s^
Symptom 4A-53 4A-54 4A-93 4A-50 4A-48 4A-50 4A—91
Runs rough on deceleration 8 6 1 7 3 4 5 2
Afterburn in exhaust system 7 3 1 4 2 5 8 6
Poor fuel consumption 2 1 6 5 4 3
High idle speed after warm up 2 1 3
Fails emission test 4 2 1 5 3 6 7 8 9
76G04A-081
FE 8Valve (General)
Possible cause main air bleed control
solenoid valve
Engine control unit terminal
Possible cause main air bleed control
solenoid valve
MTX ATX
Possible cause main air bleed control
solenoid valve
E F B 2F j 21
Page 4A—51 4A—90 4A—89
Checking order 1 2
76G04A-082
F6 (Singapore)
Possible cause
X^Page
Symptom

Dashpot

(Only

MTX)
Anti-afterburn
valve

idle

switch
L
Coasting

leaner

solenoid

valve
Engine

control

unit

terminal

Possible cause
X^Page
Symptom

Dashpot

(Only

MTX)
Anti-afterburn
valve

idle

switch
L
Coasting

leaner

solenoid

valve
B D
Possible cause
X^Page
Symptom 4A—50 4A—50 4A—93 4A—56 4A—92
High idle speed after warm up 1
Runs rough on deceleration 1 2 3
Afterburn In exhaust system 5 4 1 2 3
Fails emission test 4 1 2 3
76G04A-083
4A—47

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
V\ i \\ I M
p)
/ 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