1992 MAZDA 323 ECU

F3 CONTROL SYSTEM
PRESSURE REGULATOR CONTROL SYSTEM
SOLENOID VALVE TO MAIN RELAY
(PRC HIGH TEYP.)
t ECU
I
PRESSURE REGULATOR
// VACUUM

IJ WATER
THERMOSENSOR
F----------- lNTAKE AIR
THERMOSENSOR
SWITCH SOLEltolD VALVE
(PRC LOW TEMP.)
TO FUEL TANK
13EOF3-31 To prevent vaporlock in the fuel system during hot restart idle, a two-stage pressure regulator is adoped
to the new 323 4WD.
Low temperature operation: The vacuum to the pressure regulator (A and B ports) is cut (solenoid valve
[low temp.] UN), and the fuel injection pressure is increased to 284 kPa (2.90 kgf/cm2, 41 psi ) ,
High temperature operation: The vacuum to the pressure regulator (A port) is cut (solenoid valve [high
temp.] ON), and the fuel injection pressure is increased to 343 kPa [ 3.5 kgf/cm2, 49 psi 1.
Condition and operation
Condition Operation
1
coolant Intake alt Solenoid vrlve Solenoid vatve Opemtlon
I temperature temperature Engine (Idw temp.)
(high temp.) time Operation 40% [fU40f)-
Above 90°C 5U°C (t22OFI ON OFF 180s Low temp.
f f940Fj No load
Above 5O*C
I122OF) OFF ON 210s t-ltgh temp.
3
t3EOF3-319
F3-14 Wast
l Ins fuel
l In:; InJeci
l In:;
l Vol Injecl
l In:;
Presr
l SCI Engir
l InsI

SUPPLEMENTAL SERVICE INFORMATION .
I
The following points in this section are changed in comparison to the Mazda 323 4-Wheel Drive Work-
shop Manual [I 229-l O-89t].
Turbocharger
l Removal / Installation
Wastegate solenoid valve
l Inspection
htercooter
l Removal I Installation
Fuel pump (main)
l Inspection
Fuel pump resistor/relay
l System operation
l Inspection
Injector
l Inspection
l Volume test
Injector resistor
l Inspection
Pressure regulator control system
l Solenoid valve (pressure regulator control}
Engine control unit (ECU)
l Inspection 13EOF3.320
F3-I 5

SELF-DIAGNOSIS FUNCTION F3 I
Open or short crcuit
13EOFS322
Caution l If there is more than one failure present, the code numbers will be indicated in numerical or-
der, lowest number first.
l After repairing a failure, turn off the ignition switch, disconnect the negative battery cable,
and depress the brake pedal for at least twenty seconds to erase the service code from the
ECU memory. II
F3-17

F3 SELF-DIAGNOSIS FUNCTION
:ODE NO. 25 {SOLENOlD VALVE - PRESSURE REGULATOR CONTROL) (Low temperature opoeration)
INSPECTION ACTION
Disconnect connector from ECU; IS there battery Yes Check ECU termrnal connector for poor
voltage at ECU terminal 2T (G/C) wrth Ignition connection
switch ON?
4 If OK, replace ECU
CT page F3-2
c3 If not OK, repatr or replace connector
NO Go to next step
2 In same condition as rn Step 1. is there battery Yes Repair or replace wlrrng harness (G/O)
voltage at sofenord vatve (PRC low temp.) con-
nector termrnal wrre (G/O)?
NO Go to next step
3 Is solenord valve (PRC low temp ) UK7 Yes Check for a short or open crrcuit in WII-
CT page F343 ing harness (main relay [FUEL INJ re-
lay] - solenoid valve [PRC low temp.])
NO Replace solenord valve (PRC tow temp.)
1
t3EOF3-323
CODE NO. 35 (SOLENOID VALVE - PRESSURE REGULATOR CONTROL) (High temperature opoeration)
STEP lNSPECTlON ACTlON
1 Disconnect connector from ECU: is there battery Yes Check ECU terminal connector for poor
voltage a? ECU terminal 22 (G) with rgnttlon connection
swttch ON7
4 If OK, replace ECU
J page F3-2
e If not OK, repair or replace connector
No Go to next step
2 In same condrtron as In Step 1, is there battery Yes
voltage at solenoid valve (PRC high temp.) con- Repair or replace wiring harness (G)
nector terminal wire (G)?
No Go to next step
3 Is solenoid valve (PRC high temp ) OK7 Yes Check for a short or open circuit In wir-
r;r page F343 ing harness (marn relay [FUEL INJ re-
WI - sofenord valve [PRC high temp.])
No Replace solenoid valve
(PRC high temp.)
f3EOF3-324
Circuit Diagram
ECU
I
2T 22 I
G
TO MAIN RELAY
I SOLENOID
VALVE
(PRC HIGH TEMP.)
F3-18 :3EOf3 32 5
--
TRW
RELAT
c
-..


INPUT
--
KNOCH
--
DIAGM
(TEN T
--
IGNITIi
(STAR1
--
E/L SIC
-a
P/S PR
--
A/c SYI
--
NEUTR
SWITCI
--
STUPb
--
ATMDI
SENSQ
-a
THRUI
-..
INfAk.1
--
AlFlFLC
--
UXYGE
--
WATEF
--
DlSfRl

F3 TROUBLESHUOTING GUIDE
TROU8LESHOOTlNG GUIDE
RELATIONSHIP CHART
.

OUTPUT DEVICE
INPUT DEVICE

w
3
s
s
KNOCK SENSOR
0
0 0 0 DtAGNOStS CONNECTOR
(TEN TERMINAL)
0 0 0 IGNITION SWlTCH
(START POSITION) 0 0
0
0
0 0
0 0
0 0
0
0
0
0
0 0 0 0
E/L SIGNAL* 0
P/S PRESSURE SWITCH 0
0
A/C SWtTCH
NEUTRAL AND CLUTCH
SWITCHES
STOPLIGHT SWITCH
ATMOSPHERIC PRESSURE
SENSOR (IN ECU)
THROTTLE SENSOR
0 0 0 0
0
0
0 0’
0
0 0
0
0 0
0
’ 0
0
0 0 0 0 0 0 0
0 I
0 ~ INTAKE AIR THERMOSENSOR 0 0 0 0
0 -~
OXYGEN SENSOR
0 0 0 0 WATER THERMOSENSOR
A
0
* 0 0 0 c 0
13
3F3-32 IN, o . E/L SIGNAL: Blower fan control switch second position or higher, electric cooling fan operating, headlights
rear window defroster ON.
F3-19
i

TRUU8LESH00TlNG GUIDE F3
13EOF3-328
13EOF3-329
1
PRECAUTIONS
Fuel Pressure Release and Servicing Fuel System
Fuel
in the fuel system remains under high pressure when the engine is not running.
a) Before disconnecting any fuel line, release the fuel pres-
sure from the fuel system to reduce the possibility of injury
or fire as discribed below.
1. Start the engine.
2. Push the rear seat cushion buttons and remove the
cushion.
3. Disconnect the fuel pump connector.
4. After the engine stalls, turn off the ignition switch.
5. Reconnect the fuet pump connector and install the rear
seat cushion.
b) Use a rag as protection from fuel spray when disconnect-
ing the fuel hoses.
Plug the hoses after removal.
c) When inspecting the fuel system, use a suitable fuel pres-
sure gauge.
Caution
l install hose clamps to secure the fuet pressure
gauge to the fuei fitter and the fuel main hose to pre-
vent fuel leakage.
Pinching Hose
When pinching an air hose-or a fuel hose with pliers, wrap
the hose with a rag to prevent damage,
F3-2 t

F3 TROUBLESHOOTING GUIDE
SYMPTOM TROUSLESHOOTING
2 . CRANKS NORMALLY BUT WILL NOT START (NO COMBUSTION)
LIESCRIP-
l Engine cranks at normal speed but shows no sign of firing l Battery in normal condition
TION *Throttle valve not held fufly open while cranking (dechoke system not operating}
l Fuel in tank
UROOBLESHUOTlNG HINTS]
@ No spark
@.I low fuei tine pressure
l Ignition control malfunction @I Low engine compresslon l Ignition system component malfunction
@ No fuel injection
l Fuel pump inoperative l Ihjectors inoperative
;TEP
INSPECTION
I ACTION
1
Is strong btue spark visible at disconnected high- Yes Go to Step 3
tension lead?
NO Go to Step 2
2 Is “00” dlsplayed on Self-Dlagnosjs Checker
Yes
with ignltron switch ON? Check rgnltion system (Refer to
Troubleshooting “Misfire”)
c7 Section G
SYSTEM SELECT: 1 No
Service Code No. displayed Check for cause (Refer to specified
check sequence)
G- page
F3-16
“66” flashes
Check ECU termrnal 1F voltage
3 page W-45

Voltage: Battery vabage
(ignition switch ON)
W: SELF TEST C+ If OK, replace ECU
4 If not OK, check wiring
CT page F3-2
(ECU
- Self-Diagnosis Checker)
3
Connect diagnosis connector terminals F/P and
Yes
GND with jumper wire; IS fuel pump operating Does engine start in this condition?
sound heard wjth ignition switch ON?
4 If it does, check circuit-opening
relay
4 If it does not, go to Step 5
No Go to next step
F3-22
iTEF
6
8

__ _ 7 _-. _ , ._ _) .--.Kze - __ F3 TROU5l.ESHOOTING GUIDE
ZEP WSPECTION ACTION
9 Is engine compression correct? Yes Go to next step
e
c7 Section 82
NO Check engme condrtlon CT Section B2
Engine compression:
l Worn piston, piston rings or cylinder
1059 kPa 110.8 kgflcm2, 152 psi I-300 rpm wall
l Damaged cylr nder head gasket
*Damaged or warped cylinder head
l Improper valve seating
*Valve sticking in guide
10 Are all spark plugs OK? Yes Go to next step
c7 Section G
l Wear and carbon buildup l Plug gap l Damage No Clean, adjust
11 Try known good ECU; does condftlon rmprove’
CT page F3-2
_ -w^r- ^^<
F3-24 pc?t.
@ Air,1 l F..
et
l Irtj
TEP
2