fuel MAZDA 323 1992 Suplement Owner's Manual

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

TROUBLESHOOTING GUlDE F3
7 CRANKS NORMALLY BUT HARD TO START - AFTER WARM-UP
*
l Engrne cranks at normal speed but requkres excessive cranking time before starting after running and being
DESCRIP- hot soaked
TION
l Battery rn normal condition l Engine starts normatly when cold
*Engine runs normally at Idle (If idle condrtron is not OK, refer to “Rough idle” ~Nos. 8-l 21)
[ ~ROUBLESHOOTLNG HINTS1
[ i 5 ArrlFuel mixture too Rich - l Fuel rqection control malfunction l lnpector fuet leakage
I
TEP tNSPECTlON @ Vaporlock
l Fuel pressure not held rn fuel line after engrne IS
stopped
l Pressure regulator control system malfunction
I ACTION
1 Is “00” dispiayed on Self-Diagnoses
Checker wrth rgnrtron switch ON7
SYSTEM?_SELECT. 1
SELECT SW. A
Remove vacuum hose from pressure regulator
(port A) ancI plug rt. dOt?S engine start normally’-,
Remove both vacuum hoses from pressure regu-
lator (ports A and Bj and plug them; does en-
gine start normally7
@
PtUG
/ /
Are ECU terminal voltages OK
(especially 1 C, 20, 20 and 2T)?
w page F3-46 Yes Go to next step
No Service Code No. displayed
Check for cause (Refer to specified
check sequence) CT oaae F3-16
“88” flashes
Check ECU terminal 1F voltage
Voltage: Battery voltage
(ignition switch ON) w page F3-45
( cs> It OK. replace ECU
/ w page F3-2’
3 If not OK, check wlrtng
(ECU - Self-Dlagnosrs ChecKer)
Yes Check pressure regulator control sys-
.
tern (high temperature operation) w page F3-43
I NO Go to next step
Check pressure regulator control sys-
tem (low temperature operation)
No 1 Go to next step
Yes Go to next step
NO Check for cause
F3-27

F3 TROU8LESliOOTING GUIDE
iTEP INSPECTION
ACTtUN
5 Run engine at idle; is fuel line pressure held af-
Yes Go to next step
ter ignition switch is turned OFF?
Fuet Ijne pressure: More than 147 kPa No Plug both vacuum potts of pressure
{1,5 kgflcd, 21 pdf for 5 min. regulator;
and check if fuel line pres-
sure is held after ignition switch is
turned OFF
NSTAtl CLAMPS 4 If it is, replace pressure regulator
c3 If it is not, check fuel pump hold CT page F3-3
pressure
If fuel pump is OK, check injectors
for fuet leakage
CT- page F3-4
6 Warm up engine to normal operating tempera-
Yes
ture and stop it Change to another brand of fuel
Connect diagnosis connector terminals F/P and
GND with jumper wire for 3 minutes with rgnitlon
switch ON; does engine start easily?
No Go to next step
7 Try known good ECU; does condition improve?
Yes Replace ECU
CT page F3-3 w- page F3-3
No Change to another brand of fuel
t3EOF3
F3-28

TROUBLESHOOTING GUIDE F3
8
1 ROUGH IDLE/ENGINE STALLS AT IDLE - ALWAYS
DESCRtP- 1 l Engine starts normally but stalls or vibrates excessively at idle in every condition
TION
[TROUBLESHOOTiNG HlNTSJ @ Air/Fuel mixture tw lean @ Incorrect idle-speed l ldiespeed misadjustment l Idle-speed control malfunction
$I One or more spark plugs not firing
9 Low engine compression
B Airflow meter stuck l Air leakage l Fuel injection control malfunction
*Low fuel line pressure
@ One or more injectors clogged or not
@ Low intake air amount operating
INSPECTION
Is “00” displayed on Self-Diagnosis
Checker with ignition switch ON?
1
SYSTEM SELECT: 1
ACTION
Go to next step
Service Code No. displayed Check for cause (Refer to specified
check sequence) c7 page F3-16
“88” flashes
Check ECU terminal IF voltage
(17 page F345
--.
‘\.
Voltage: Battery v&age
(Ignition switch ON)
4 If UK, replace ECU IT page F3-2 c3 If not OK, check wiring
(ECU - Self-Diagnosis Checker) Y -SELECT SW: A
Are ECU terminal voltages OK
(especially 20, 20, and ZQ)?
D page F3-45 Yes
Gu to next step
NO Check for cause
Disconnect each high-tens&on lead at idle: does
engine speed decrease equally at each cylindeR Yes Go to Step 9
NO Go to next step
Is injector operating sound heard at idle? [ Yes Go to Step 7
t- NO Stop engine and go to next step
Yes Check if injector resistance is OK
CT page F3-41 Is there battery voltage at each injector connec-
tor (No.1 (P), No.2 (R), No.3 QV), No.4 (0)) with
ignition switch ON?
Resktance: Approx. 2.110
(at 20*C [68*F))
4 if it is, check wiring
(ECU - Injector)
c3 If it is not, replace itijector
Go to next step
NO
Is there battery v&age at injector resistor (W/R)
I .Yes
with ignition switch ON? Check mjeotor resistor
4 tf OK, check for short circuit in wir-
ing (Injector resistor-Injector)
e3 If not OK,’ replace injector resistor
Check for open circuit in wiring (Main
relay (FUEL INJ relay)-Injector resistor)
Go to next step
t NO 1
Is strong blue soark visible at each disconnected Yes
‘Check ‘high-tension lead
4 If UK. check distributor cap and
rotor .
c3 If not OK, replace high-tension lead
‘-F3-29

F3 TROUBLESHUOTING GUIDE
TEPI tNSPECTION ACflON
e If OK, replace injector
4 If not OK, check for cause w Section 82
(Upper vacuum hose to pressure regulator 4
If pressure quickly increases,
check pressure regulator
4 If pressure
gradually increases,
check for clogging between fuel
pump and pressure regulator
if hose is not clogged, check fuel
pump maximum pressure
I
12 Is engine compression correct? Yes Go to next step w Sectlon 82
Engine
compression: 1059 kPa (10.8 kgf/cm2, 152 psi]-300 rpm NO Check for cause w Section B2.
13 Connect System Selector to diagnosis connector
Yes Try known good ECU; does condition
and $et Test Switch to SELF TEST; is ignition improves? w page f3-3 timing correct at idle after warm-up?
ignition timing (BTDC): 10 * to
NO Adjust ignition timing
F3-30
7
*
10
DES&
HON
-*
ITEP
2
3
4

TROUSLESHOOTING GUIDE F3
10 ROUGH IDLE/ENGINE STALLS AT IDLE - AmER WARM-UP
DESCRIP- -Engine runs normalty at idle during warm-up but engine stalls or vibrates excessively after warm
TlO#
TROUBLESHOOTING HINTS]
3 Idle-speed control system malfunction
3 Air/Fuel mixture too lean
l Air leakage
*Low fuel line pressure
TEP
INSPECTION
1
ts “00” dlsplayed on Se\-Diagnosis Checker
with ignition switch ON?
SYSTEM SELECT: 1 @ Air/Fuel mixture too rich
l Fuel injection control malfunctlon
(correction for coolant tem$eratuie)
@ Poor ignition
@ Low engine compresslon
ACTION
YES Go to next step
No Service
Code No. displayed
Check for cause (Refer to specified
check sequence)
w page F3-16
“88” flashes Check ECU terminal IF voltage w page F345
Voltage: Battery voltage
(ignition switch ON)
W: SELF TEST e !f UK, replace ECU
w page F3-3 c3 ff not OK, check wiring
(ECU - Self-Diagnosis Checker)
2 Are ECU termrnal voltages OK Yes Go to next step
(especially 20, 20, and 2Q)?
w page F3-45 No
Check for cause
3 Disconnect each high-tension lead at idle; does Yes Go to next step
engine speed decrease equally at each cylinder?
NO Go to Step 9
4 Is intake manifold vacuum correct at idle? Yes Go to next step
Vacuum: More than 450 mmHg f 17.7 InHg )
NO Check for air leakage of intake air sys-
tem components
5 Is air cleaner element clean? Yes Go to next step
No Replace air cleaner element
F3-3 1

F3 TROUBLESHOOTING GUIDE
3TEI ACTION
Is fuel line pressure correct at Idle?
*
Fuel line pressure: 265-314 kPa
12.7-3.2 kgf/cm’, 38-46 psi]
(Two vacuums hose to pressure regulator
disconnected)
304-392 kPa [ 3.1-4.0 kgf/cm’, 44-57 psi 1
(Upper vacuum hose to pressure regulator
disconnected)
INSTALL CLAMPS Yes Go to next step
No Low pressure
Check fuel line pressure while pinching
fuel return hose
4 If pressure quickly Increases,
check pressure regulator
e If pressure gradually Increases,
check for clogging between fuel
pump and pressure regulator
If hose is not clogged, check fuel
pump maxrmum pressure
Connect System Selector to diagnosis connector
and set Test Switch to SELF TEST; is ignition
tlmlng at idle correct after warm-up?
Ignition timing (BTDC): 10 f lo Yes Go to next step
No Adjust tgnrtkon system
8 Dtsconnect water thermosensor connector; does
engine condrtlon Improve? Yes Replace water thermosensor
No
Try known good ECU. does condltlon
Improve?
w page F3-13
Go to next step
Check if injector resistance is OK
w page F3-42 9 Is jqector operating sound heard at Idle?
Yes
No
Resistance: Approx. 2.11 Q
(at 20°C 168*F])
4 If it is, check wlnng
(ECU - Injector)
c3 If it Is not, replace injector
Go to next step IO
Yes Is engine compressron cprrect?
w Section G
No
Engine compression:
1059 kPa 110.8 kgf/cm2, 152 psi)-300 rDm
is strong blue spark vrslble at each disconnected
hrgh-tension lead?’ Check engine
3 Section B2
17
Yes Go to next step
No Check high-tension lead
w Section G
c3 If UK, check distrrbutor cap and
rotor
3 If not OK, replace htgh-tensron lead
Try known good ‘ECU: does condrtron
Improve7
w page F3-3 12 Are spark plugs.OK?
w Section G
l Wear and carbon butld up l Piug gap l Damage Yes
NO
Clean, adjust
13EOi3.334
F3-32.

TROUBLESHOOTING GUlbE F3 1
14 IDLE MOVES UP AND DOWN/IDLE HUNTS
IESCRLP-
l Engine speeds up and down periodically at idle
UON
TROUBLESHOOTING HINTS]
B Idle switch (En throttle sensor) OFF at idle
3 Air leakage
3 Fuel injection amount Inconstant
. Poor contact point inside airflow meter
9 Poor ignitron
rEP[ INSPECTION
I is “00” displayed on Self-Dragnosis Checker
with ignrtron swatch ON?
SYSTEM SELECT: i I ACTfON
Yes Go to next step
NO Service Code No. displayed
Check for cause (Refer to specified
check sequence) c=;r page F3-16
“86” flashes

Check ECU terminal IF vottage csr page F345
Voltage: Battery voltage
W: SELF TEST (ignition switch ON)
SELECT SW: A
.d P/ e If OK, replace ECU CT page F3-3
c3 If not OK, check wrrjng
(ECU - Self-Dlagnosls Checker)
2 Is intake manrfold vacuum correct at idle? Yes Go to next step
Intake manifold vacuum:
More than 450 mmHg { 17.7 inHg )
No Low vacuum
Check for air leakage at intake air
system
3 Is air cleaner element clean? Yes Go to next step
No Replace abr cleaner element
4 Disconnect each hrgh-tension lead at idie; does Yes Go to next step
engine speed decrease equally at each cylinder?
No Go to Step 8
5 Are ECU terminal voltages OK? Yes Go to next step
(especially 20, 2Q, 20) -
rI7 page F345 No
Check for cause
6 Connect System Selector to diagnosis connector Yes Go to next step
and set Test Switch to SELF TEST; is ignition
timing at idle correct after warm-up?
Ignition timing (BTDC): f 0 f la
No Adjust ignition timing
._
. F3-33

TROUBLESHOOTING GUIDE
(at 20% [SS*F])
If It is, check wiring
e If OK, check distributor cap and
rotor
e If not OK, replace high-tensjon lead
12 Are spark plugs UK? Yes Is engine compresston correct? w Section 82
w Section G
. Wear and carbon burld up Engine compression: l Plug gap 1059 kPa 110.8 kgf/cm*, 352 psi I-300 rpm l Damage
4 If OK, go to next step
4 If not OK, check for cause
w Section 82
c
NO Clean, adjust
13 Check for injector leakage Yes
Replace injector
No Go to next step
14 Try known good ECU: does condition improve?
w page F3-45
----- Am.*
F3-34
~ROlJ8L Engine so:
3 Idle-sp.
T> fuel-cL