1992 MAZDA 323 fuel pressure

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

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

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

TROUBLESHOOTING GUlDE F3
STEP INSPECTION ACTlON
4
Is there buttery voltage at fuel pump connector Yes
* (G/R) with lgnitron switch ON and F/P terminal Check contmurty of fuel pump
between termrnafs G/R and 8
Check ctrcutt openmg relay
5
Is qector operating sound heard whtle engine IS Yes Go to Step 8
being cranked?
No Go to next step
CcI page F3-45
+ If 0K;check for a short cjrcult rn
wiring harness
(Injector reastor-Injector)
=D If not OK, replace Injector reststor
fuel Line pressure: 265-314 kPa
12.7-3.2 kgflcd, 38-46
psi)
if fuel return hose is clogged or
t, replace pressure
CT psge F3-3
F3-2 3

TROUBLESHOOTING GUIDE F3
4 CRANKS NORMALLY 8UT WILL NOT START (PARTfAL COMBUSTION) - AFTER WARM-UP
&RIP-
l Engine cranks at nurmal speed and shows partial combustion but will not Continue running after being hot
soaked
FION
l Battery in normal condltlon
*Engine starts normally when cold
TROUBLESHOOTING
HINTS] 3 Air/Fuel mixture too rich @ Vaporlock
ssure not held in fuel line after engrne IS
GND mth jumper wire tor 3
minutes with ignition
Fuel
line pressure: 265-314 kPs (2.7-3.2 kgflcm2, 38-46 psi 1
c3 If pressure
quickly increases,
check pressure regulator
4 If pressure
gradually increases,
check fuel line and filter lor
clogging
If hose is not clogged. check fuel
pump maximum pressure
High pressure Check if fuel return hose is clogged or
restricted
INSTALL CLAMPS e If rt is not, replace pressure
regulator
@ It It 6. repalr or replace it CT page F3-3
F3-25

F3 TROUBLESHOOTING GUIDE
I- STEP lNSPECTlON ACTION
Yes Go to Step 8
5 In same condition as in Step 2, IS fuel ilne pres-
sfire held after Igrxtbon swatch rs turned OFF?
Fuel line pressure: More than 147 kPa
Il.5 kgflcm’, 21 Psi 1 for 5 min.
6 In same condition as in Step 3, IS fuel line pres-
sure held after lgnltron switch IS turned OFF?
Fuel line pressure: More than 147 kPa
{ t.5 kgf/cm*, 21 psi) for 5 min.
No
I Go to next step
Plug both vcuum ports of pressure regulator; IS
fuel lme pressure held after ignltlon switch is
turned OFF? Yes Replace pressure regulator
r~ page F3-3
Fuel line pressure: More than 147 kPa
{ 1.5 kgf/crn*, 21 psi] for 5 min.
NO Check fuel pump hold pressure
e If OK, check InJector for fuel
leakage
e If not OK reptace fuel pump ZF- page F3-42
T page F3-3
8 Dlscofinect water thermosensor connector, does
engtne start? Yes Check water thermosensor
e ff OK. check connectrons of water
thermosensor and ECU 2Q terminal
Q If not OK, replace water thermo-
sensor
ET page F3-13
No 1 Go to next step --~
Is “00” drsplayea on Self-Diagnosis Checker
with ignition switch ON? 9 Yes Go to next step
NO Service Code No. displayed
Check for cause (Refer to specified
check sequence)
c7 page F3-16 SYSTEM SELECT, 1
“88” flashes
Check ECU terminal IF voltage
KIT page F3-45
Voltage: Battery voltage
(ignition switch ON)
e If OK, replace ECU
ET- page F3-2
e If not OK, check wiring
(ECU - Self-Diagnosis Checker)
Y %EtECT SW: A
Yes 1 Go to next step 10 Are rf ECU termrnaf voltages are OK?
(especjaffy 1C. 2D. and 2Q)
CT page F3-45
NO Check for cause
Yes Replace ECU
=T page F3-2
No Change to another brand of fuel
13EOF3 331 Try known good ECU, does condition improve?
CT page F3-2
F3-26