engine MAZDA 232 1990 Suplement Repair Manual

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.
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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

F2 CONTROL SYSTEM
KNOCK CONTROL SYSTEM [BP TURBO]
This svstem retards the ignition timina when enaine knocking occurs because of usage of low octane fuel, etc.
1NTAKE
MANIFO
KNOCK SENSOR
(INSTALLED BETWEEN No.2 AND
No.3 CYLINDER)
IGNITER
KNOCK iX?NTROL
UNIT
Operation
When the engine vibrates, the knock sensor generates a slight voltage signal that is the sent to the knock
control unit. The knock control unit determines whether the signal is a knocking signal. If it is a knocking
signal, the ignition spark is retarded according to the intensity of the knock to a maximum of 4O.
Inhibition of spark retardation
In order to improve drivability and fuel economy, the ECU inhibits the above spark retardation when the
‘engine load Ls light, the coolant temperature is below O°C (32OF), the engine is cranking during engine test
conditions.
Note
l The knock ~ensur and knock control unit cannot be inspected individually.
When a matfunction code number 05 is indicated, replace the knock controt unit or sensor
only after inspecting the related wiring and connectors.
F2-22

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

F2 CONTROLSYSTEM
AK CUT-OFF SYSTEM (AI-X)
To improve the retiability of the engine at high temperature condition, the water thermoswitch on the radiator
is switched OFF above approx. II I “C (232OF) and stops the A/C operation.
ECU
NC OPERATION BLOWER FAN
WATER
THERMOSWITCH
IABOVE
111 OC (232OF): OFF]
NC SWITCH
IGNITION
T
l 1
BLOWER SWITCH
MAGNET
CLUTCH
93GOF2-73
F2-24

SUPPLEMENTAL SERVICE INFORMATION F2
SUPPLEMENTAL SERVICE INFORMATION
The following points in this section are changed in comparison to the Mazda 323 Workshop Manual
[I 203-I U-89F (Europe) or 120410-89F {Australia)].
intake air system components [BP Turbo]
l Removalllnspectionll nstaltation
WASTEGATE [BP Turbo]
l Inspection
WASTEGATE SULENOlD VALVE [BP Turbo]
l Inspection
Turbocharger [BP Turbo]
l Inspection
l Removalllnstaltation
Air bypass valve [BP Turbo]
l Removal/hstallation
l 1 nspection
lntetcoolet [BP Turbo]
l RemovaMnspection/tnstaltation
Fuel tank
l Removal ! Inspection I Installation
Fuel pump control unit [BP Tubto]/4x4 control unit [BP SOHC]
l 1 nspection
l Replacement
Transfer pump switch
l Inspection
l Replacement
Transfer pump
l Inspection
l Replacement
Fuel pump resistor/relay
l System operation
l Inspection
injector [8P Turbo]
l Volume test
Exhaust system components
l Removal / 1 nspection / Installation
Engine control unit (ECU) [BP Turbo]
l Terminal voftage
Oxygen sensor [BP Turbo]
l Inspection
l Replacement
Knock sensor [BP Turbo]
l Replacement 93GOFZ736
F2-25

F2 TROUBLESt=iUUTlNG GUIDE
SYMPTOM TROUBLESHOOTING
Regarding symptom troubleshooting except LACK OF POWER, POOR XCELERATION, KNOCKING, and
HIGH UIL CONSUMPTION, refer to Workshop Manual [I 203-l O-89F (Europe) or 1204-l O-89F (Australia)].
19 LACK OF POWER [BP TIJR801
DESCRIP- *Performance poor under load when throttle valve wide open
TION *Reduced maximum speed
l Idle condition normal
[TROUBLESHOOTING HINTS1
3 Wastegate always open or opens early
3 Turbocharger damage
@ Factors other than engine malfunction
*Clutch sllpping
l Brake dragging
*Low tire pressure
l Incorrect tire size l Overloaded vehicle
@ Low intake air amount
*Throttle valve not open fully
*Clogged intake air system
TEP INSPECTlON
1
Install pressure gauge in intake air pipe and
check boost pressure at engine speed of
4,000
wm
CT page F2-45
Boost pressure:
More than 2.0 kPa (0.02 kglcm2, 0.3
psi)
@ Air/Fuel mixture lean
l Fuel iine pressure decreases l Fuel injection malfunction
@ Poor ignrtjon
@ Low engine compression
@ Alcohol blended fuel used
@ Knock control system malfunction
ACTION
Yes Go to Step 3
NO Check for air leakage and exhaust gas
leakage
4 If OK, go to next step
4 In not OK, repair
2 Check wastegate
Yes Remove intake air pipe from turbo-
f7 page F2-45 charger and check if compressor wheel
rotates smoothly t7 page F2-46
4 If OK, check air cleaner element
and throttle valve
+ If not OK, replace turbocharger
3 Check factors other than engrne Yes
l Clutch slipping Go to next step
1 8rake dragging
’
l Low tire pressure NO Repair or adjust
l Incorrect tire srze
FZ-32

TROUBLESHUOT1NG GUIDE F2
;TEP
14
15
16 Change fuel and check if condjtjon improves INSPECTION
Check if resistance of rgnrtm
coil IS OK’
Resistance (at 20°C [SS*Fj):
Primary coil winding _....-.. Cl.81 -0.99Q
Secondary coil winding.,.. IO-16 kQ ACTION
Yes Go to next step
PRIMARY COIL
WINDING SECONDARY COIL
WIND tNG
Check fur correct engine compressron”
Yes Go to next step
Engine compression:
785 kPa (8.0 kg/cm2, 1 I4 psi)-300’ rpm L 1
No Check engine condition *
l Worn p&ton, piston rings or cylinder
wall
l Defective cylinder head gasket l Distorted cylinder head l Improper valve seating
l Valve sticking in guide
Yes Change fuel to another brand
No
I I Try known good ECU and check if con-
dition imDroves
* Refer to 323 Workshop Manual [ 1203-lo-89F (Europe) or 1204-l O-89F (Australia)l.
93GOF2-74 6
F2-35