1990 MAZDA 232 engine

F2
FUEL AND EMISSION
CONTROL SYSTEMS
(WITH CATALYTIC CONVERTER)
.
INDEX ..*.........**.*.........*..........*...... F2- 2
OUTLINE ...................................... F2- 4
OUTLINE OF CONSTRUCTION.. .... F2- 4
SYSTEM DIAGRAM ...................... F2- 5
VACUUM HOSE ROUTING
DIAGRAM [BP TURBO] ............... F2- 7
WIRING DlAGRAM.. ..................... FZ- 8
ECU REtATlONSHIP DIAGRAM
[BP TURBO] .............................. F2-10
SPEClFtCATlONS. ........................ F2-11
TURBOCHARGER CONTROL
[BP TURBO] ................................ F2-I 2
OUTLINE .................................... F2-I 2
SYSTEM DIAGRAM ................. .; ... F2-12
WASTEGATE CONTROL ...............
F2-13
FUEL,SYSTEM
.............................. F2-15
OUTLINE
.................................... F2-15
CONSTRUCTlON ......................... F2-15
FUEL VAPOR VALVE ................... F2-16
FUEL PUMP CONTROL SYSTEM.. . F2-16
FUEL PUMP RESISTOR/RELAY ...... F2-18
TRANSFER PUMP CONTROL. ....... F2-I 8
CONTROL SYSTEM ....................... F2-20
STRUCTURAL VIEW.. ................... F2-20
OVERBOOST WARN!NG BUZZER
[BP TURBO] .............................. F2-21
TURBOCI-IARGE INDICATOR
[BP TURBO] .............................. F2-21
KNOCK CONTROL SYSTEM
[BP TURBO] .............................. F2-22
OXYGEN SENSOR [BP TURBO]. .... F2-23
PRESSURE REGULATOR CONTROL
SYSTEM [BP TURBO] ................. F2-23
A/C CUT-OFF SYSTEM (ATX) .........
F2-24 SUPPLEMENTAL SERVICE
INFORMATION ............................. F2-25
SELF-DIAGNOSIS FUNCTION .......... F2-26
OUTLINE
.................................... F2-26
MALFUNCTION CODE NUMBERS . . F2-26
TROUBLESHOOTtNG GUIDE
[BP TURBO1
................................ F2-31
RELATlONSHlP CHART ................ F2-31
SYMPTOM TRUUBLESH0OTlNG .... F2-32
tNTAKE AIR SYSTEM ..................... F2-43
COMPONENTS ............................ F2-43
TURBOCHARGERCONTROL
SYSTEM ...................................... F2-45
PREPARATION ............................ F2-45
SYSTEM OPERATION ................... F2-45
WASTEGATE ............................... F2-45
WASTEGATE SOLENOID VALVE.. .. F2-46
TURBOCHARGER ........................ F2-46
AIR BYPASS VALVE ..................... F2-48
INTERCOOLER ............................ F2-49
FUEL SYSTEM .............................. F2-50
PREPARATION ............................ F2-50
PRECAUTION ............................. F2-50
FUEL TANK
................................ F2-51
TRANSFER PUMP CONTROL
SYSTEM ................................... F2-52
FUEL PUMP CONTROL UNIT ........ F2-53
TRANSFER PUMP SWITCH ........... F2-54
TRANSFER PUMP.. ...................... F2-54
FUEL PUMP RESISTOR/RELAY ...... F2-56
INJECTOR
.................................. F2-56
EXHAUST SYSTEM
COMPONENTS .................................................... ;ff;
CONTROL SYSTEM ....................... F2-59
PREPARATION
............................ F2-59
ENGINE CONTROL UNIT (ECU) ..... F2-59
OXYGEN SENSOR ....................... F2-68
KNOCK SENSOR ......................... F2-69
93GOF2.701

SOLENOID VALVE
CHECK VALVE
r----+ (PURGE CONTROL)
CHiRCOAL
I CANISTER
INTERCOOLER 11 ’ 1 ‘I A-4
II II -
AIR , BYPASS
II ,.-ok----,/ ,CHECK VALVE
(TWO-WAY)
1-1
---II
-d KNO&
II II I I II VALVE
VALVE
THERMOSENSOR
c
I 31c
SENSOR 1 k---k FUEL FILTER
TRANSFER
PUMP
WASTEGATE 7
II t I III TURtiOCHARGERI~
I SOLENOID I II - i 1 WASTFGATF II I
AlOCI fuAl RAlz-rCD
VALVE
le-SIGNAL* -
EJ 0
G-SIGNAL-
DISTRIBUTOR
CATALYTIC CONVERTER ftl”FLLt”” IVIL I =r,
(WITH INTAKE THERMOSENSOR)
*TO ENGINE CONTROL UNIT

F2 TURBOCHARGER CONTROL [BP TURBO]
TURBOCHARGER CONTROL [BP TURBO]
OUTLINE
l The air-to-air intercooler is adopted to lower intake air temperature and to improve engine performance.
l With addition of the wastegate control system, engine torque at higher rpm is increased.
AIR BYPASS VALVE
WASTEGATE
SOLENOID VALVE
TURBOCHAR
ACTUATOR
-
SYSTEM DIAGRAM
AIR BYPASS VALVE 1
t
!NTERCOOLER
n Ii Y7rzFes-~ m I
-
TUREiOCHARGER
WASTEGATE SOLENO1D VALVE
93GOF2-7 7
FZ-12

TURBOCHARGER CONTROL [BP TURBO] F2
WASTEGATE CONTROL
The engine control unit controls the wastegate solenoid valve to give higher boost to the engine in the higher
rpm range, increasing engine torque
and power.
System
Diagram
I
t
1 ECU
i i
AIRFLOW METER ACTUATOR
WASTEGATE
WASTEGATE
SOLENOID VALVE
r ACTUATOR
WASTEGATE SOLENOID VALVE
: OFF (VALVE CLOSED)
ACTUATOR
BOOST
PRESSURE
WASTEGATE SULENOlD VALVE
: ON (VALVE OPEN) Operation
Engine speed below 5,300 rpm
The
wastegate solenoid valve is OFF. Boost pressure is ap-
plied directly to the actuator and the wastegate opens when
the boost pressure exceeds 49 kPa (0.5 kg/cm , 7.1
psi).
Engine speed above 5,300 rpm
The wastegate
solenoid valve is UN. Some boost pressure is
bypassed to the intake manifold, limiting the opening of the
wastegate to increase boost pressure and
improve engine per-
formance.
F2-13

F2 TURBOCHARGER CONTROL [BP TURBO]
93GOF.Z721
!=2-14 LARGE
+ FULLY OPEN
BYPASS AIR
i 8EGlNNIp
AMOLIN OF OPEN
SMALIL
430 VACUUM
(5-l) mmt-lg
TURBOCHARGER OnW
INLET
lntercooler
The air-to-air intercooler utilizes fresh air flow through the in-
tercooler core to reduce the intake air temperature.
If
the air compressed by the turbocharger was sent directly
into the combustion chamber without passing through the in-
tercooler, the charging air efficiency would be
reduced by the
high temperature of the intake aii-.
The intercooler, by cooling this high temperature air, substan-
tially increases the charging air efficiency
and engine output,
as well as supressing ignition knocking by reducing the com-
bustion gas temperature.
The intercooler is mounted at
the left front of the vehicle.
Air Bypass Valve
The air bypass valve bypasses intake air from the air funnel
to before the turbocharger in order to reduce air vibration noise
during deceleration.
When the throttle valve is closed suddenly during high-rpm
and heavy-load operation, air vibration occurs between the
throttle vatve and the turbocharger as a result of pressuriza-
tion
caused by inertia of the intake air. This system prevents
such noise.

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
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93GW2-725
FZ-17

CONTROL SYSTEM
WE~DOST WARNlNG BUZZER [BP TURBO]
To improve engine reliability, the overboost warning buzzer installed in the instrument cluster sounds during
overboost conditions as detected by engine
speed and intake air amount caiculations within the ECU. The
driver is thus warned to reduce engine
speed.
DETECTtON
OVERBOOST
BUZZER
TURBOCHARGE INDICATOR [BP TURBO]
When the turbocharger boost pressure calcul’ated by intake air amount and engine speed reaches the predeter-
mined level and the transaxle is in gear, the turbocharge indicator illuminates to inform the driver of turbocharge
operation.
1
AIRFLOW METER
DISTRI BUTUR
rd” i
4 NEUTRAUCLUTCH
SWITCH ECU
* CALCULATION
-, OF
BOOST
PRESSURE
TURBOCHARGE
INDICATOR