1987 MAZDA 626 battery

4B TROUBLESHOOTING WITH SST
Code No. 25 (Solenoid valve-Pressure regulator) PC: Possible Cause

Is there battery voltage
at
(RB) wire
of
solenoid valve
connector?

NO
PC: Poor connection
of
connector
or
open circuit
in
wiring harness from (RB) wire
to
main relay (for engine control unit)

YES

PC: Poor connection
of
connector
or
open circuit
in
wiring harness from (RB) wire
to
main relay (for engine control unit)

YES
NO
Is there continuity
of
solenoid valve?
NO
Replace solenoid valve

YES

Is there continuity between solenoid valve and engine control unit?
Solenoid valve Control unit
B (WR wire) 2K

NO
PC: Open circuit
in
wiring harness from solenoid valve
to
engine control unit

YES
PC:
•
Short circuit
in
wiring harness • Engine control unit malfunction

76G04B-017
Code No. 26 (Solenoid valve-Purge)
YES
PC:
•
Short circuit
in
wiring harness • Engine control unit malfunction

76G04B-018
4B—22

4B SWITCH MONITOR FUNCTION
49 H018 9A1
INSPECTION PROCEDURE
1. Warm up the engine to normal operating temper-
ature and stop it.
2. Connect the SST to the check connector (Green,
6-pin) and the negative battery terminal.
86U04A-034
76G04B-023
3. Connect a jumper wire between the test connec-
tor (Green, 1-pin) and a ground.
4. Turn the ignition switch ON. Check if monitor lamp
illuminates when each switch is made to function
as described below.
Caution
a) If any one of the switches is activated, the
monitor lamp will stay on.
b) Do not start the engine.
Note
The Digital Code Checker (49 G018 9A0) with
the Signal Adapter (49 9200180) may be used
in place of the Self-Diagnosis Checker.
Procedure
76G04B-024
4B—26

4B IDLE-UP SYSTEM
AIR VALVE
Pre-inspection
1. Start the engine and run it at idle.
2. Pinch the bypass air hose and check that the en-
gine rpm drops.
When engine still cool RPM reduced
After warming-up RPM drop within
200 rpm
3. If the speed is not reduced when cold, check the
air valve, or check for vacuum leaks at the bypass
air hose.
4. If the speed drop is more than 200 rpm when
warm, check the air valve and current to the valve.
Inspection of Terminal Voltage
1. Disconnect the connector from the valve.
2. Remove the rubber boot from the connector.
3. Start the engine and run it at idle.
4. Check that there is battery voltage at terminal (WY),
using a voltmeter.
5. If not correct, check the circuit opening relay and
wiring harness.
76G04B-046
Inspection of Air Valve
1. Check the valve for operation.
Temperature 20°C (68°F) Valve open
(When engine cool)
After warming-up Valve closed
2. Replace valve if faulty.
76G04B-047
4B—38 expert22 Arm http://rutracker.org

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 IDLE-UP SYSTEM
76G04B-052
76G04B-053
76G04B-054
Hot idle compensation
1. Warm up the engine and run it at idle.
2. Connect a voltmeter between the terminal F, D and
ground.
3. Remove the air cleaner upper case assembly.
4. Heat the intake air thermo sensor to more than
55°C
(131
°F).
5. Check that the meter shows OV.
6. If not correct, check the intake air thermo sensor
(Refer to page 4B—94).
E/L (Electrical load)
1. Warm up the engine and run it at idle.
2. Connect a voltmeter between the F terminal and
ground.
3. Apply the E/L.
E/L:
• Headlight • Rear defroster
• Electrical fan motor
• Blower motor (3rd or 4th position)
4. Check that the meter shows OV.
5. If not correct, check the electrical load control unit
(Refer to page 4B—93).
Adjustment
1. Warm up the engine and run it at idle.
2. Turn all accessories OFF.
3. Connect a tachometer to the engine.
4. Disconnect the air bypass solenoid valve con-
nector.
5. Check the idle speed and adjust it if necessary.
6. Apply battery power to each BAT terminal and
ground each GRD terminal as shown in the table.
7. Check that the engine speed is within specification.
76G04B-055
Valve BAT GRD Engine speed

A (for A/C) A B 1,250—1,350
rpm

B (for high altitude and high intake
air
temp.) C D 900—1,000
rpm
(MTX)
1,000-1,100
rpm
(ATX)
C (for P/S, E/L, high intake
air
temp., high altitude and
hot
idle compensations)
E F
900—1,000
rpm
(MTX)
1,000-1,100
rpm
(ATX)

4B—40

4B FUEL SYSTEM
FUEL SYSTEM
76G04B-057
This system supplies the fuel necessary 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 switch (incorporated in the air flow meter), and the circuit opening relay.
The fuel pump is mounted in the fuel tank to minimize the operating noise of the fuel pump. The injec-
tors are directly supplied with battery voltage through the main relay.
4B—42

FUEL SYSTEM 4B
Pressure .
regulator ^^ \ To multi-pressure tester
How to Connect Multi-Pressure Tester
Warning
Before connecting the SST, release the fuel
pressure from the fuel system to reduce the
possibility of injury or fire. (Refer to page
4B—45.)
1. Disconnect the negative battery terminal.
2. Disconnect the fuel main hose from the fuel filter.
3. Connect the SST between the fuel main hose and
fuel pump with the adapter.
Caution
Do not reverse the adapter connection.
4. Disconnect the vacuum hose from the pressure
regulator control solenoid valve. Connect the SST
vacuum hose with a three-way joint.
5. Connect the negative battery terminal.
6. Connect the SST to the battery.
86U04A-071
v *
- i\zLTest connector (Yellow)
7. Connect the terminals of the test connector (Yel-
low) with a jumper wire. Turn the ignition switch
ON to operate the fuel pump.
8. Check for fuel leaks.
Caution
After checking for fuel leakage, turn the igni-
tion switch OFF and disconnect the jumper
wire from the test connector.
86U04A-072
4B—47

4B FUEL SYSTEM
v - \\N . Test connector
VW^^^^^^AX (Yellow)
76G04B-070
4. Connect the fuel return hose and vacuum hose to
the pressure regulator.
5. Connect the terminals of the fuel pump test con-
nector with a jumper wire. Turn the ignition switch
ON.
6. Check that no fuel leaks from the injector nozzles.
Note
After 1 minute a drop of fuel from the injec-
tor is acceptable.
7. Connect the SST to the battery and injector.
8. Check the injection volume with a graduated con-
tainer.
Injection volume:
Approx. 38—53 cc (2.3—3.2 cu in) /15 sec.
Caution
When using the SST, make sure of the SST
number and use correct one.
9. If not correct, replace the injectors.
76G04B-071
4B-52