1987 MAZDA 626 Workshop Manual

4A IDLE-UP CONTROL SYSTEM
IDLE-UP CONTROL SYSTEM
SINGLE-SERVO DIAPHRAGM TYPE
With P/S
Solenoid valve
(for P/S)
Servo diaphragm
Ign switch
©J
P/S switch
69G04B-122
69G04B-123
4A—68

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
TROUBLESHOOTING
FE and F8 (ECE, Hong Kong, and Singapore)
Possible cause o a> > 10 0)
c o o 0>
c
E »
E o> IS k_ « c a> > •o o c O <
o
CO Ifl o> k_ a.
o> e Ul
** c 3
a. as •a 0 £ 01 co
M
E 3
> •o o c a> o CO
£ O
5
o M a 3 • 0)
O <
o a % o £
Refrigerant
switch

ATX MTX
a. as •a 0 £ 01 co
3 O
> •o o c a> o CO
CO CO
o M a 3 • 0) >< 10 V EC
a> £ H Refrigerant
switch
H P
a. as •a 0 £ 01 co >
> •o o c a> o CO £ 2
>< 10 V EC
a> £ H Refrigerant
switch

Page 4A—86 4A—88 4A—72 4A—74 4A—74 4A—75 4A—76 Section 16
Checking order 9 2 3 4 5 1 6 7 8
76G04A-133
F6 (Singapore)
Possible
cause 3
O w ** C E OI (0 £ Q. 10
o
a> im 3 8
>>
o 0) c at c Ul
E OI (0 £ Q. 10
o
10 c o> 0)
E 3
a> > To >
TJ o c
£ O $
CO
£ O **
"5 CO
O <
k O >•
s M O E
a.
c a k_ ® r-
n ® OC All
terminal
£ w CO
O a >
a> o CO O < (0 a
a «> DC
« £ 1-
OC
«
Page 4A—57 4A—92 4A—72 4A—74 4A—74 Section 15 4A—75 Section 16
Checking order 9 10 1 2 3 4 5 6 7 8
76G04A-134
FE and F8 (General)
Possible
cause o 01 > 0)
c o 0 0> c 01 c Ul
unit

termina

Servo
diaphragm
M C at CO
E 3

Solenoid

valve £ o **
S
> •o o c a> o CO a
O
k o
** s CO o £

Refrigerant

pressu

switch

ATX MTX
Servo
diaphragm 3 O

Solenoid

valve
CO CO 3 i >• 10 a> OC
a>

Refrigerant

pressu

switch
H P Servo
diaphragm
>
Solenoid

valve
CL 2
>• 10 a> OC I-
Refrigerant

pressu

switch

Page 4A—89 4A—90 4A—72 4A—74 4A—74 4A—75 4A—76 Section 16
Checking order 9 2 3 4 5 1 6 7 8
76G04A-135
4A-70

IDLE-UP CONTROL SYSTEM 4 A
FE (Middle East) and F6 (General)
Possible cause
jrvo

diaphragm

3
jrvo

diaphragm

n c o> (0
E 3 3 O
® >
a >
•o o c e
£ O **
S M O
£ O
'i (0 (0
O <
o a
o E W 0)
lm Q.
c a k 4) -
9-5
"S "5 (O > CO < a. DC H Js * OC M
Page 4A—72 4A—74 4A—74 Section 15 4A—75 Section 16
Checking order 1 2 3 4 5 6 7 8
76G04A-136
FE 8Valve—Unleaded Fuel
Posible cause

Engine

control

unit

terminal

Servo

diaphragm

Vacuum

signal

Solenoid

valve £ O **
S CO O
£ U
S <0 U) Relay
(for
A/C) ** n ** w o E «
Refrigerant
pressure

switch
H D I Servo

diaphragm

Vacuum

signal

Solenoid

valve
< a. Relay
(for
A/C)
H Refrigerant
pressure

switch

Page 4A—91 4A—72 4A—74 4A—74 Section 15 4A—75 Section 16
Checking order 9 1 2 3 4 5 6 7 8
76G04A-137
4A—71

4A IDLE-UP CONTROL SYSTEM
Servo Diaphragm
Dual servo diaphragm type
1. Warm up the engine and run it at idle.
2. Connect a tachometer to the engine.
3. Disconnect the vacuum hose from the servo di-
aphragm port A.
4. Apply intake manifold vacuum directly to the di-
aphragm.
Caution
All accessories must be OFF.
76G04A-138
5. Check that the engine speed is within the specifi-
cation.
Engine speed: 1,200—1,400 rpm
6. If not within specification, turn the adjust screw to
adjust.
7. Reconnect the vacuum hoses.
76G04A-139
8. Disconnect the solenoid valve vacuum hose from
the servo diaphragm port B.
9. Apply intake manifold vacuum directly to the di-
aphragm.
10. Check that the engine speed is within specification.
Engine speed: 800—1,000 rpm (MTX)
1,050—1,250 rpm (ATX)
(in N range)
76G04A-140
Adjust screw
11. If not within specification, turn the adjust screw to
adjust.
12. Reconnect the vacuum hoses.
76G04A-141
4A—72

IDLE-UP CONTROL SYSTEM 4A
Single servo diaphragm type
1. Warm up the engine and run it at idle.
2. Connect a tachometer to the engine.
3. Disconnect the vacuum hose from the servo di-
aphragm.
4. Check that the engine speed is within specification.
Engine speed:
P/S operated 800—1,000 rpm (MTX) P/S operated 1,050—1,250 rpm (ATX) (in N range)
A/C operated 1,200—1,400 rpm
76G04A-142
6. If not within specification, turn the adjust screw to
adjust.
76G04A-143
4A-73

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

IDLE-UP CONTROL SYSTEM 4A
5. Apply 12V and ground to the solenoid valve with
jumper wires.
6. Blow air through the valve from hose A and check
that it comes out of port B.
7. Replace if necessary.
76G04A-148
Solenoid Valve (P/S)
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 not come out of port B.
76G04A-149
5. Apply 12V and a ground to the solenoid valve with
jumper wires.
6. Blow air through the valve from hose A and check
that it comes out of port B.
7. Replace if necessary.
76G04A-150
4A-75