1992 MAZDA 323 engine

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

TROUBLESHOOTING GUiDE F3
15 ENGINE STALLS ON DECELERATION
IESCRIP-
l Engrne unexpectedly stops running dunng or after deceleration
[iON l Idle condition normal.
TROUBLESHOOT1NG HtNTS]
ingrne speed drops too much when releasrng accelerator
3 Idle-speed misadjustment @I Loose connector disconnected by force of deceleration
3 Fuel-cut contrd malfunction
TEP lNSPECTlON ACTION
1 1s idle condition normal? Yes Go to next step
tdle speed: 800 f 50 rpm (in neutral)
NO Adjust or perform Troubleshooting, Nos.
8-I 1 “ROUGH IDLE”
(Refer to Workshop Manual
(1203-I o-89F))
2 Is “00” displayed on Self-Diagnosis Checker Yes Go to next step
with ignition switch ON?
SYSTEM SELECT: 1 NO Service Code No. displayed
Check for cause (Refer to specified
check sequence) ET page F3-16
“88” flashes
Check ECU termrnal 1 F voltage
Voltage: Battery voltage
(ignition switch ON) r;r page F346
W:SELFTEST
e If OK, replace ECU CI page F3-3
4 If not OK, check wirtng
(ECU - Self-Diagnosis Checker)
3 Does Self-Diagnosis Checker Monitor Lamp with Yes Go to next step
lgnttlon switch UN show that switches operate
correctly?
NO Lamp not ON or OFF with specified
switch
Check for cause (Refer to specified
check sequence)
W: SEtF TEST Lamp slways ON
Check wiring between
(ECU terminal 1 D - Self-Diagnosis
Checker)
4 Are ECU ?erminal voltages OK? Yes Go to next step
(especially IV, 20, 20, ZU, 2V.
and 20) v page F346 No
Check for cause
5 Check for poor connection of foltowing parts YC?S Repair or replace
l ignrtion coil l Igniter l Olstribdor l High-tension lead
NO Go to next step l Injector. l Injector resistor l Ctrcuit-opening relay . l ECU
F3-35

F3 TROUBLESHOOTING GUIDE
STEP INSPECTION ACTlON
6 Is dashpot correctly adjusted? Yes Go to next step
c
Dashpot set speed: Approx. 3,500 rpm
No Adjust dashpot
7
Try known good ECU; does condition
Improve?
w page F3-3
13EOF3-336
16 ENGINE STALLS SUDDENLY (INTERMITTENT)
DESCRIP.
l Engine intermittently stops running
TION l Before stalling, engine conditron is OK
TROUBLESHOOTING HINTS]
@ intermittently no spark or no fuel injection caused by ve-
hlcle vibratron, acceleratton, or deceleration
l Poor connectlon in wiring harness
iTEP INSPECTION ACTfON
1 Is “00” displayed on Self-Oiagnoss Checker Yes Go to next step
with lgnltlon swrtch ON?
NO Service Code No. displayed
Check for cause (Refer to speclfled
check sequence).
Note CT page F3-16
l When checking wiring harness and
connectors, tap, move, and wiggle
suspect sensor and/or harness to
recreate problem
“88” flashes ’
Check ECU terminal IF voltage
Voltage: Battery voltage
{ignition swttch ON) w page F3-45
4 If OK, replace ECU
4 If not OK, check wiring
(ECU - Self-Diagnosis Checker)
2 Check for poor connection of foliowrng parts
Yes Reparr or replace
l lgnltfon coil l Igniter l Distributor l t-flgh-tensron lead
No Go to next step l Injector l Injector reststor l Circutt-opening relay l ECU
3 Are ECU terminal voltages OK? Yes Go to Troubleshbotrng No. 2
(especially 16, 2A, 2B, and 2C) .“CRANKS NORMALLY BUT WILL NOT
w page F3-45 START (NO COMBUSTION)”
w page F3-20
Note
. No Check for cause
l When. checking voltages, tap, move, and
wiggle harness and connector to recreate
problem
* lrlrl m-7
F3-36
7.8-l