1990 MAZDA 232 relay

F2 OUTUNE
OUTLINE OF CONSTRUCTION
The fuel and emission control system of the new 323 4WD model is basically the same as that of the new
323 2WD modet; however, a turbocharger and knock control system are added to the BP TURBO model
and the fuel tank is designed
with separate right and left sections due to the installation of the propeller shaft
for the 4-wheel-drive system. A transfer pump is also equipped to pump the fuel from the left
to the right
(fuel pump side) section of the fuel tank.
The major points of difference between the 2WD model and 4WD model are as shown below.
93GOF2-705
Difference
Component 2WD 4WD
BP SUHC BP OOHC BP SOHC BP TURBU Remark
INTAKE AG! 1 Resonance duct 0 0 0 - -
SYSTEM
Resonance chamber 0
0 G -
VICS .-
ui- - -
Turbocharger - - -
0 Refer to page
FZ-12
I ntercooler - - -
0 Refer to page FZ-14
Air bypass valve - - -
0 Refer to page F2-14
FUEL SYSTEM Fuel pump control - - -
0 Refer to page F2-16
Transfer pump - -
0 0 Refer to page F2-18
Operating time for BP
Pressure regulator control 0 0 0 0
TURBO is different
(Refer to page F2-23)
Fuel pump reststorlrelay - - -
0 Refer to page F2-18
EVAPORATIVE
EMISSION
Fuel vapor vatve - -
CONTROL 0 0 Refer to page F2-16
SYSTEM
CONTROL
SYSTEM Point type
0 0
Throttle sensor 0 (MTX) -
-
Variable type - -
0 W-x) 0
Without heater
0 0 0 -
Oxygen sensor F
With heater - -
- 0 Refer to page F2-23
Water thermoswitch (on radiator)
-
Knock control system -
Overboost wami ng buzzer -
Turbocharge Indicator - -
C @TX) - NC cut-off system
- - 0
Refer to page F2-22
- -
0 Refer to page F2-21
- - 0 Refer to page F2-21
93GOF2-706

lNDEX F2
4x4 CONTROL UNIT
(FUEL PUMP
CONTROL UNIT)
SERVICE, SECTION SEAT
1. Fuel tank
Removal / Inspection I
lnstailation . . . . .._........._._....... 1 . . . . page F2-51
2. Injector _
Volume test ~..........~..~..,...~..~....~. page F2-56
3. Fuel pump resistor/relay [BP TURBO]
System operation . . ._. . . ._. _ . . . . . . . . . . . page F2-56
Inspection . . . . . . . . . . . . . . . . . . . *. . . . . . . . . . . . . page F2-56 4. Fuel pump control unit [BP TURBO]
Inspection *....,...,.........I..... * . . . . . . . page F2-53
Replacement . . . . . . . . . . . . . . . . . . . . . . . . ..-... page F2-53
5. Transfer pump switch
Removal I InstaNation . . . . . . . . . , ..,... page F2-54
Inspection ..a . . . . . . . . . . . . . . . . . . * . . ..I.. e... page F2-54
6. Transfer pump
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page F2-54
Replacement ,...,_..... b . .._._......_.... page F2-54
1. Exhaust system
RemovA I Inspection I InstaNation
BP SOHC . . . . __.._......... _........... page F2-57
BP TURBO _.. . . . . . .._.. . . . . . . . . . . . . . . . page FZ-58
F2-3

F2 OUTLINE
ECU RELATIONSHIP DlAGRAM [BP TURBO]
INPUT DEVICE KNOCK SENSOR
KNOCK
i( CONTROL
DlSTRlBUTOR ,-, UNIT
NC SWITCH
--k/L SWITCHS
{REAR WINDOW DEFROSTER SWITCH.
HEADLIGHT SWITCH, BLOWER SWITCH,
ELECTRICAL FAN SWITCH)
BATTERY A
THRO77LE
SENSOR
NEUTRAL/ IDENTIFICATION
CLUTCH SWITCH
DIAGNOSIS
CONNECTOR
(TEN TERMINAL) INTAKE AIR
THERMOSENSOR
OUTPUT DEVICE
CIRCUIT
OPENING
SOLENOID VALVE
(PRESSURE REGULATOR
WASTEGATE
SOLENOID VALVE
RESISTOR/RELAY
SOLENOID VALVE
(PURGE CONTROL)
93GOFZ-71
F2-10

F2 FUEL SYSTEM
FUEL VAPOR VALVE
FUEL VAPOR VALVE
93GOF2-722
The fuel vapor valve is installed in the fuel tank to allow fuel vapors within the tank to escape to the charcoal
canister.
The fuel vapor valve contains a shut-off valve to prevent raw fuel from escaping during hard cornering
01
at other times when there is significant fuel slosh.
FUEL PUMP CONTROL SYSTEM [BP TURBO]
Outline
l The fuel pump control system supplies electric power to the fuel pump at ail times while the engine is
running. The fuel pump can thus operate even though the fuel pump switch in the airflow meter OFF.
rhe fuel pump switch may open (switch OFF) on deceleration due to back-flow of air from the turbocharger.]
l To improve fuel pump longevity, the fuel pump is controlled by the engine control unit (ECU). (Refer to
next page.)
MAIN RELAY (FUEL 1NJ RELAY)
I I FUEL PUMP
RESISTOR/RELAY ECU
I
ON
P CIRCUIT OPENING
I--
DIAGNOSIS
CONNECTOR
TERMINAL F/P CPU
F2-16

FUEL SYSTEM F2
Two-stage WeI pump operation
Engine running (Except heavy load or cranking)
The ECU 1 I circuit is ON, opening the contact plate in the fuel pump resistor/relay. Current from the circuit
opening relay to the fuel pump flows through the resistor in the fuel pump resistor/relay, and the voltage
to the fuel pump is reduced to approx. WV, causing the fuel pump to operate at a reduced speed to im-
move fuel pump longevity.
MAIN RELAY
Engine under heavy load or cranking
The ECU 1 I circuit is OFF and the contact plate in the fuel pump resistor/relay is closed. Unreduced battery
current flows to the fuel pump through the contact plate, causing the fuel pump speed and output to be
increased to meet the demands of the engine.
I
L
:: _:
:.i
I,. I,
:: :
_:. :
. . :
:: :_
.:: 1.
pi ‘.
. . ::
:: :_ c
-. .>:
i :: . . . . . . . . .
:; .::..:.y ::.
. . . . . . . ..__. I
93GW2-725
FZ-17

F2 FUEL SYSTEM
93GOF2-726
FUEL PUMP RESISTOR/RELAY [BP TURBO]
The fuel pump resistorlretay supplies battery voltage to the
fuel pump when the ECU 11 circuit is OFF, and approx. 1 OV
when the ECU 11 circuit is ON. It is mounted on the firewall.
TRANSFER PUMP CONTROL
Outline
The fuel tank is buitt with separate right and left sections to accommodate the. installation of the propeller
shaft. As fuel is puited from the right side of the tank, the transfer pump pumps the fuel from the left to the
right (fuel pumb) side to balance the fuel level.
FUEL IN LEFT TANK
I
FUEL PUMP CONTROL. UNIT
/ TRANSFER PUMP
TRANSFER PUMP SWITCH: OFF
NO FUEL IN LEFT
TANK
FUEL PUMP CONTROL UNIT / TRiNSFER PUMP
TRANSFER PUMP SWITCH: UN
93GOF2-727
Operation 1. Whenever the ignition switch is ON and fuel is in the left (transfer pump)
side of the fuel tank the fuel pump switch is open, the transfer pump circuit in the fuel pump control unit is
closed, and the transfer pump
operates.
2. When the fuel in the left side of the tank drips betow a specified point, the fuel pump switch is grounded
and the transfer pump stops operation.
3. To prevent the transfer pump from
being turned ON and OFF repeatedly, possibly shorting the life of the
pump, when the vehicle is driven on a rough
road and the fuel level is low, there is a ten-second delay
circuit in the control unit to delay the turning ON and OFF the pump.
f2--I 8

F2 CONTROL SYSTEM
CONTROL
SYSTEM
STRUCTURAL VIEW
OXL STOPLIGHT SWITCH CLUTCH SWITCH
INJECTOR
P/S PRESSURE
SWITCH
‘GEN SE877
DtSTRIBUTOR
/ PUMP
CONTROL UNll
CONTROL UNIT
CONNECTOR
P REStSTORlRELAY
FUEL tNJ RELAY (MAIN RELAY)
AIRFLOW METER
SOLENOID VALVE
I NEUTRAL SWITCH
(PRESSURE REGULATOR)
WATER THERMOSENSOR
93GOf2.729

CONTROL SYSTEM F2
t OXYGEN SENSOR [BP TURBO]
I
CERAMlC HEATER
93GOF2-733
Because the temperature of the exhaust gas is inherently low in turbocharged engines, the BP Turbo model
uses a rapid heating ceramic heater to detect the air/fuel ratio,
PRESSURE REGULATOR CONTROL SYSTEM [BP TURBO]
PRESSURE
REGULATOR
I SOLENOID VALVE
(PRESSURE REGULATOR CONTROL)
FUEL
+ (FROM
DELIVERY PIPE1
II
FUEL INJ I
RELAY
(MAIN REU\Y)
I
II Ir
-__. _ - -’ VACUUM
CT0 DYNAMIC
Ill
CHAMBER)
BATTERY -
c
FUEL
(TO FUEL TANK)
nme*rn -.-a
To prevent percolation of the fuel during hot restart idle, vacuum to the pressure regulator k cut for 180
sec., and the fuel injection pressure is increased to slightly more than 284 kPa (2.90 kg/cm’, 41.2 psi).
Operating condition
l Coolant temperature: Above 90°C (194OF)
l Intake air temperature: Above 58OC (136OF)
g No-load condition
FZ-23