steering MAZDA 626 1987 User Guide

IDLE-UP CONTROL SYSTEM 4A
DUAL-SERVO DIAPHRAGM TYPE
With P/S and A/C
Solenoid valve (for P/S)
69G04B-124
Operation
A/C ON and compressor operating
Current flows through the A/C relay to the two-way solenoid valve for the A/C. Vacuum port A is opened,
and vacuum is applied to the servo diaphragm, which in turn pulls the throttle plates slightly open
at low speeds.
P/S operating
Current flows through the P/S switch to the three-way solenoid valve for power steering. Vacuum port
B is opened and vacuum is applied to the servo diaphragm, which in turn pulls the throttle plates slightly
open.
Relationship
Equipment
Type P/S A/C P/S & A/C
Single-servo
diaphragm type O O
Dual-servo
diaphragm type O
4A—69

4A IDLE-UP CONTROL SYSTEM
76G04A-144
76G04A-145
76G04A-146
Vacuum Signal [Equipped with A/C, only FE and
F8 (Except Middle East and General)]
1. Start the engine and run it at idle.
2. Disconnect the vacuum hose from the servo di-
aphragm.
3. Place a finger over the hose.
4. Increase the engine speed, and check for vacuum.
Engine model Engine speed Vacuum
pj| (Except Middle) Below 2,300 rpm Yes pj| (Except Middle) Above 2,300 rpm No
FE (Unleaded fuel) Below 1,500 rpm Yes FE (Unleaded fuel) Above 1,500 rpm No
F6 (Singapore) Below 2,100 rpm Yes F6 (Singapore) Above 2,100 rpm No
General and Middle East
1. Start the engine and run it at idle.
2. Disconnect the vacuum hose from the servo di-
aphragm.
3. Place a finger over the hose.
4. Operate the A/C or P/S.
5. Check that vacuum is felt.
P/S Switch
1. Start the engine and run it at idle.
2. Disconnect the power steering switch connector.
3. Connect an ohmmeter to the power steering
switch.
4. Turn the steering wheel all the way to either the
right or left, and check for continuity.
P/S Continuity
Operated Yes
Not operated No
5. Replace if necessary.
Solenoid Valve (A/C)
1. Disconnect vacuum hose A from the servo di-
aphragm.
2. Disconnect vacuum hose B from the solenoid
valve.
3. Disconnect the solenoid valve connector.
4. Blow air through the valve from hose A and check
that it comes out of port C.
76G04A-147
4A-74

4B IDLE-UP SYSTEM
COMPONENT DESCRIPTIONS
Component Function Remarks
Air bypass solenoid
valve

Controls bypass
air
amount Operates A: A/C
: ON

B: Intake
air
temp, high
or at
high
al-
titude C: P/S
:
ON, E/L applied
or
hot start

Air valve
When cold, supplies bypass
air
into
dy-

namic chamber
• Engine speed increased
to
shorten
warm-up period
• Bimetal type

Atmospheric pressure sensor

Detects atmospheric pressure; sends sig-
nal
to
engine control unit

E/L control unit
Detects electrical load applied; sends sig-nal
to
engine control unit

Engine control unit
Detects signals from input sensors and switches; controls
air
bypass solenoid valve

Intake air thermo sensor
Detects intake
air
temperature; sends sig-
nal
to
engine control unit
Installed
in air
flow meter

P/S pressure switch
Detects P/S operation; sends signal
to
engine control unit P/S:
ON
when steering wheel turnefl right
or
left

76g04b-044
4B-36

IDLE-UP SYSTEM 4B
AIR BYPASS SOLENOID VALVE
Inspection of Idle-up Signal
A/C
1. Warm up the engine and run it at idle.
2. Connect a voltmeter between terminal A and
ground.
3. Turn the A/C and blower motor switches ON.
4. Check that the meter shows battery voltage.
5. If not correct, check the A/C relay, A/C switch,
blower motor switch, fuse,and wiring harness.
76G04B-048
P/S
1. Warm up the engine and run it at idle.
2. Attach a voltmeter between the terminal F and
ground.
3. Turn the steering wheel all the way to either the
right or left.
4. Check that the meter shows OV.
5. Release the steering wheel.
6. Check that the meter shows battery voltage.
7. If not correct, check the P/S pressure switch (Re-
fer to page 4B—92) and wiring harness.
76G04B-049
High altitude compensation
1. Warm up the engine and run it at idle.
2. Connect a vacuum pump to the atmospheric pres-
sure sensor.
3. Connect a voltmeter between the terminals shown
in the following table and ground.
4. Apply vacuum to the atmospheric pressure sen-
sor as shown in the table using a vacuum pump.
5. Check that the voltmeter shows OV.
76G04B-050
J
O
6. Release the vacuum.
7. Check that the voltmeter shows battery voltage.
8. If not correct, check the atmospheric pressure sen-
sor (Refer to page 4B—99) and wiring harness.
Terminal Vacuum Amount

F Approx. 155 mmHg (6.10 inHg)
D Approx.
85
mmHg (3.35 inHg)

76G04B-051
4B-39

4B CONTROL SYSTEM
P/S pressure switch-^—^
86U04A-176
P/S PRESSURE SWITCH
Inspection
1. Disconnect the P/S pressure switch connector.
2. Connect an ohmmeter to the switch.
3. Start the engine. Check continuity of the switch
while turning the steering wheel at idle.
P/S Continuity
Turning Yes
Not turning No
4. Connect the switch connector after checking.
Note
Refer to section 10 for replacement of the P/S
pressure switch.
INHIBITOR SWITCH
Inspection
1. Disconnect the inhibitor switch connector.
2. Connect an ohmmeter to the switch.
3. Check continuity of the switch.
Position Continuity
P and N ranges Yes
Other ranges No
4. Connect the switch connector after checking.
Note
Refer to Section 7B for replacement of the in-
hibitor switch.
4B—92

4C OUTLINE
SPECIFICATIONS
Item Engine type Unleaded Fuel Leaded Fuel
Idle speed rpm 750 ± 50
Throttle body
Type Horizontal draft (2-barrel)
Throat diameter mm (in) No. 1 46 (1.8) Throat diameter mm (in) No. 2 40 (1.6)
Fuel pump
Type Impeller (in tank)
Output pressure kPa (kg/cm2, psi) Main pump: 441-588 (4.5—6.0, 64—85) Transfer pump: 20—25 (0.20—0.25, 2.8—3.6)
Feeding capacity cc (cu in)/10 sec. Main pump: More than 220 (13.4) Transfer pump: More than 190 (11.6)
Fuel filter
Type Low pressure side Nylon element Type High pressure side Paper element
Pressure regulator
Type Diaphragm
Regulating pressure kPa (kg/cm2, psi) 235-275 (2.4 -2.8, 34-40)
Injector
Type High-ohmic
Type of drive Voltage
Resistance G 12--16
Injection amount cc (cu in)/15 sec. 66-91 (4.03-5.55)
Idle speed control valve
Solenoid resistance a 6.3--9.9
Fuel tank
Capacity liters (US gal, Imp gal) 60 (15.9, 13.2), 57 (15.0, 12.5): 4-wheel steering vehicle
Air cleaner
Element type Dry
Fuel
Specification Unleaded (95 RON or more) Leaded or unleaded fuel
(95 RON or more)
76G04C-008
4C-8

ISC SYSTEM 4C
COMPONENT DESCRIPTION
Component Function Remark
A/C switch Detects air conditioner operation; sends
signal to engine control unit Switch ON when air conditioner
operating
Air valve When cold, supplies bypass air into dy-namic chamber • Engine speed increased to shorten warm-up period • Thermo wax type
• Installed in BAC valve
Clutch switch Detects in-gear condition; sends signal to engine control unit Switch ON when clutch pedal released
E/L control unit Detects that E/L is being applied; sends
signal to engine control unit
Engine control unit Detects signals from input sensors and switches; controls solenoid valve (Idle speed control)
Idle switch Detects when throttle valve fully closed;
sends signal to engine control unit
Installed on throttle body
Ne signal pick-up Detects crank angle at 180° intervals; sends signal to engine control unit Installed in distributor
Neutral switch Detects in-gear condition; sends signal to engine control unit
Switch ON when in gear
P/S pressure switch Detects P/S operation; sends signal to engine control unit Switch ON when steering wheel turned right or left
Solenoid valve (Idle speed control) Controls bypass air amount • Controlled by duty signal from engine control unit • Installed in BAC valve
• Operates idle-up
Test connector For initial idle speed adjustment • Gerrn, 1-pin
• Idle speed feedback control cancelled when connector grounded
Water thermo sensor Detects coolant temperature; sends
signal to engine control unit
76G04C-078
4C—45

ISC SYSTEM 4C
76G04C-081
76G04C-082
Cooling fan switch
Rear defroster switch
Head light switch
Blower motor switch
ISC "valve
76G04C-083
(ISC valve)
6. Connect the ISC valve connector.
Note
a) Make sure that the initial idle speed is set
to specification.
b) All accessory must be OFF.
7. Again disconnect the ISC valve connector (engine
at normal operating temperature).
8. Check that the engine speed decreases.
9. Reconnect the ISC valve connector.
10 Remove the jumper wire from the test connector
and make sure that the idle speed is within specifi-
cations.
(Load Test)
11. Apply power steering, electrical, and air conditioner
loads and check that the idle speed is controlled
to within specifications.
Load Idle speed
P/S 750 ± 50
E/L 800 ± 50
A/C 800 ± 50
E/L and A/C 800 ± 50
BAC Valve
Air valve
1. Remove the BAC valve from the throttle body.
2. Blow air through the valve from port A and check
that air comes out of port B when the BAC valve
is cold..
3. If not correct, replace the BAC valve.
Note
Refer to "Installation" on this page for the
BAC valve installation.
86U04A-063
4C—47

FUEL SYSTEM 4C
FUEL SYSTEM
76G04C-087
This system supplies the necessary fuel for combustion at a constant pressure to the injectors. Fuel
is metered and injected into the intake manifold according to the injection control signals from the en-
gine control unit. It consists of the fuel pump, fuel filters, delivery pipe, pulsation damper, pressure
regulator, injectors, fuel pump control unit, and the control relay.
The fuel pump is mounted in the fuel tank to minimize the operating noise of the fuel pump. The injec-
tors directly supplied with battery voltage through the control relay. The connector of the injectors is
white to distinguish the injectors for FE DOHC from those of other engines.
Due to the installation of the steering angle transfer shaft for the 4-wheel steering (4WS) the fuel tank
of 4WS vehicles is designed with separate right and left sections. A transfer pump is used to pump
fuel from the left side to the right side.
4C—49

FUEL SYSTEM 4C
5. Connect the SST to the battery and injector.
6. Check the injection volume with a graduated con-
tainer.
Injection volume:
Approx. 66—91 cc (4.03—5.55 cu in) /15 sec.
Caution
When using the SST, make sure of the SST
number and use correct one.
7. If not correct, replace the injector.
76G04C-107
Rear seat Cushion Release Button -
76G04C-108
TRANSFER PUMP CONTROL SYSTEM (4 WHEEL
STEERING)
1. Remove the rear seat. (Refer to 14 section.)
2. Remove the fuel filler cap.
3. Turn the ignition switch ON.
Note
a) The tank should be more than 1/3 full.
b) Due to the delay timer, transfer pump oper-
ation begins approx. 10 sec. after the igni-
tion switch is turned ON.
4. Listen for the operational sound of the transfer
pump.
5. Install the fuel filler cap.
6. If no sound was heard, check the voltage at the
transfer pump connector.
Terminal (wire) Voltage
A, C (WG) Approx. 12V
I, J (B) OV
86U04B-075
I C A
lb d
cp a • • •
J
76G04C-211
7. If the voltages are correct, replace the transfer
pump.
8. If not correct, disconnect the transfer pump con-
nector.
9. Check the voltage at the terminals below.
Terminal (wire) Voltage
A, C (WG) Approx. 12V
I, J (B) OV
10. If the voltages are correct, replace the transfer
pump.
4C—59