ECU MAZDA 232 1990 Suplement Owner's Guide

F2 TROUBLESHOUTING GUIDE
I 22 KNOCKtNG [8P TURBO] I
IESCW-
l Abnormal combustron accompanied by audible “pinging” noise rim
TROUBLESHOOTING HtNTS]
3 incorrect ignition timing (Too advanced) @ Low octan fuel used
2
Knock control system malfunction @ Air/Fuel mixture lean
3 Carbon deposits in cylinder l Fuel injection amount not correct
3 Overheating l Fuel line pressure decreases while accelerating
TEP INSPECTION ACTlON
1
Connect System Selector to diagnosis connector Yes Go to next step
and set Test Switch to “SELF TEST” and check
for correct ignition timing at idle after warm-up’
ignition timing: BTDC 10 f lo
No Adjust
2 Check if “00” is displayed on Self-Diagnosis Yes Go to next step
Checker with igmtlon switch UN*
No Matf unction Code No. displayed
Check for cause (Refer to specified
check sequence) *
“88” flashes
Check ECU terminal 1 F voltage
Vottage: Approx. 12V
(Ignition switch ON) 0 page FZ-60
4 If OK, replace ECU
W: SELF TEST
4 If not OK, check wiring between
ECU and Self-Diagnosis Checker
3 Check for correct fuel line pressure at idle* Yes Check if fuel Iine pressure decreases
when accelerating quickly
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm2, 38-46 psi)
(vacuum hose to pressure regulator dis-
connected) 4 If decreases, check for clogging
between fuel pump and pressure
regulator
e If no decrease, go to next step
No tow pressure Check
fuel line pressure while pinching
fuel return hose
3 If fuel line pressure quickly in-
creases, check pressure
regulator*
4 If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and
pressure
regutator
If not clogged, check fuel pump
maximum pressure*
- -
.-
Refer to 323 Workshop Manual [1203-IO-89f (Europe} or t204-IO-89f (Australia)]. F2-40

I
F2
fNSPECTlON ACTION
I Check if cootrng system IS OK’
YES Go to next step
No Repair or reptace
l Thermostat l
l Electric cooling fan * l Radiator*
5 Try known good ECU and check if condltlon Yes Replace ECU * rnproves
NO Change fuel to another brand or use
higher octane fuel
l Refer to 323 Workshop Manual [1203-l O-89F (Europe) or It 204-I O-89F (Australia)]. %%‘3OF2-748 -
F2-4 I

F2 FUEL SYSTEM
FUEL
SYSTEM
PREPARATlON
SST
49 LO18 901
Injector checker For
lnsgectlon of
injector
93GOF2.770
9MUOF2-722
03UOFX-7 27
F2-50
PRECAUTION
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 fife,
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 stalts, turn off the ignition switch.
5. Recpnnect the fuel pump connector and install the rear
seat cushion.
b) Use a rag as protection from fuel spray when disconnect-
ing the 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 fuel pressure
gauge to the fuel filter and the fuel main hose to pre-
vent fuet leakage.
Priming Fuel System
After releasing the fuel pressure for repairs or inspection, the
system must be primed to avoid excessive cranking when first
starting the engine. Follow the steps
below.
1. Connect the diagnosis connector terminals F/P and GND
with a jumper wire.
2. Turn the ignition switch
ON for approx. 10 set, and check
for fuel leaks.
3. Turn the ignition switch OFF and remove the jumper wire.

F2 FUEL SYSTEM
93GOF2-775
1 93GOF2-78(
93GOF2-78:
1
93GOF2-78;
-
93GOF2-783
FUEL PUMP RESISTOR/RELAY
System Operation
I. Remove the rear seat cushion.
2,
Measure the voltage at the fuel pump connector terminal
A {G/O).
Voltage
r Crankinq Approx. 12V
I
I- Others t ACKXOX. I OV i
3. If not within specification, perform the following inspection,
and repair or replace if necessary.
l Fuel pump resistor/relay resistance. (Refer to below.)
l ECU II terminal voltage. (Refer to page F2-60.)
l Wiring harness and connector.
inspection
1.. Disconnect the connector.
2. Ground the fuel pump resister relay terminal D.
3. Apply 12V to terminal C and check for continuity between
terminals A and B.
Terminal C
12 applied
ov Continutty between A and B
NO
Yes
4. Measure the resistance between terminals E and F.
Resistance : 0.62-0.66Q [at 20% (68OF)l
INJECTOR
Volume Test
1. Remove the injectors with the delivery pipe.
2. Affix the injectors to the delivery pipe with wire.
Caution
l Affix the injectors firmly to the delivery pipe so that
no movement of the-injectors is possible.
Warning
l Be extremely careful when working with fuel.
Always work away from sparks or open flames.
3. Connect the SST to the battery and injector.
4. Check the injection volume with a graduated container.
Injection volume:
BP SUHC....44-47 cc (2.68-2.87 cu in)/15 sec.
BP Turbo
. ...87-105 cc (5.31 -6.41 cu in)/15 sec.
Caution
l When using the SST, make sure of the SST num-
ber and use correct one.
5. If nut correct, replace the injector(s).

CONTROL SYSTEM F2
CONTROLSYSTEM
PREPARATION
SST
49 HOt8 9A3
Self-dragnosls
checker
Engrne signal
IT-iOFlllO~ 49 GO18 904
Sheet System selector
I 93GUF2-786
For inspection of ECU
93GOF2-787
93GOF2-801
TERMNALS 1
--I”- -
03UOFX
ENGINE CONTROL UNIT (ECU)
Inspection
1. Disconnect the ECU connectors.
2. Connect the SSTs (Engine Signal Monitor and Adapt-
er) to the ECU as shown.
3. Place
the SST (Sheet) 011 the Engine Signal Monitor.
4. Measure the voltage at each terminal.
(Refer to pages FZ-60 to F2-67.)
5. If any ECU terminal voltage is incorrect, check the related
input or output devices and wiring. If no problem is found,
reptace the ECU. (Refer to above.)
Caution l
Never apply voltage to SST terminals A and B.
F2-59

CONTROL SYSTEM F2
Incorrect voltage Possible cause
Always OV
l ROOM 10A fuse burned l Open circuit in wiring from ROOM 10A fuse to ECU termrnal IA
Always OV
I l Main relay maifunctlon l Open or short crrcu~t in wirrng from main relay to ECU termrnal 1 B
Always OV (Srarrer turns)
l Open or short circuit in wiring from ignition switch to ECU terminal 1C
Always UV
l Main relay (FUEL INJ relay} malfunctron l Open circuit in wiring from main relay to diagnosis connector terminal + B l Open or short circuit in wiring from dragnosls connector terminal MEN to
ECU terminal 1D
Always approx. 12V
I . Poor connection at ECU connector
l ECU matfunction
Always approx. 5V
l ECU malfunction
-
I -
Always below No disptay on Self- . Main relay (FUEL INJ retay) malfunction (Refer to page F3-142)
2.5V Diagnosis Checker l Open circuit in wiring from main relay to diagnosis connector termjnal + B
“88” displayed and
l Open or short circuit in wiring from diagnosis connector terminal FEN to
buzzer sounds con- ECU terminal 1 F
tinuously
Always approx. 12V
l Poor connection at ECU connector l ECU malfunction
Always OV
l Short circuit in wiring from igniter to ECU terminal tG
Atways OV or approx. 12V
l Refer to Code No.42 Troubleshooting (Refer to page F2-30)
Always approx. 12V
l Fuel pump resistor/relay malfunction
Always OV
l Open or short circuit in wiring from ECU terminal 1 I to resistor/retay
Always below
A/C does not operate
l AJC relay malfunction
23 l Open circuit in wiring from ignition switch to NC relay l Open circuit in wiring from A/C relay to ECU terminal IJ
A/C switch OFF but
l Short circuit in wiring from A/C relay to ECU terminal IJ
AIC operates
l ECU matfunction
Always approx. t2V
Always below 1 .OV
l Poor connection at ECU connector l ECU malfunction
l Short circurt in wiring from diagnosis connector terminal TEN to ECU termi-
nal 1K
Always approx. 12V
l Open circutt in wiring from diagnosis connector terminal TEN to ECU termi-
nal lK
l Open c~rcud in wiring from diagnosis connector terminal GND to ground
Always above 1 .OV
I
l Open circuit in wiring from ECU terminal 1 M to ground
F2-61

CONTROL SYSTEM F2
Incorrect voltage
Always below 1 .OV Possible cause
l Throttle sensor misadjustment l Short circuit in wiring from throttle sensor to ECU terminal IN l ECU malfunction
Always approx. f 2V
Atways below 1 .OV (Stopfights OK)
Always below 1 .OV
l Throttle sensor misadjustment l Open circuit in wiring from throttle sensor to ECU terminal IN l Open ctrcuit in wiring from throttle sensor to ECU terminal 20
l Open crrcurt in wiring from stoplight switch to ECU terminal 10
l P/S pressure switch malfunction l Short circuit in wirrng from P/S pressure switch to ECU termrnai 1 P
l ECU malfunction
Always approx. 12V
Atways below 2.5V (Btower fan OK) . P/S pressure switch malfunction
l Open circuit in wiring from P/S pressure switch to ECU terminal I P l Open circuit in wiring from P/S pressure switch to ground
l A/C switch malfunction l Short circuit in wiring from A/C switch to ECU terminal 1 Q l Poor connection at ECU connector l ECU malfunction
Always approx. 12V (Blower fan OK)
l ’ A/C switch malfunction l Open c~rcurt in wiring from NC switch to ECU terminal 1Q l ken circuit H-I winnu from A/C switch to blower control switch
Always below 1.W
l Open or short circuit in wiring from fan relay to ECU terminal IR
(Electrkal cooling fan UK} l ECU malfunctron
Always below 1 .OV (Blower fan OK)
l Short crrcutt in wiring from blower control swrfch to ECU terminal IS l Poor connection at ECU connector l ECU malfunction
Always approx. 12V (Blower fan OK)
Always below Illumination lamp
1.w ON when rear
window defroster
switch ON 1
l Open circurt in wrring from blower control switch to ECU terminat IS
I
l Open or short circuit rn wiring from rear window defroster switch to ECU
terminal 1 T
ftlumination lamp
never ON
l Open circuit in wiring from ignition switch to rear window defroster switch
l Rear window defroster switch malfunction I
Always below 1 .OV (Headlights OK)
l Open or short circurt in wiring from headlight relay to ECU termtnal 1 U
Always below 1 .OV
Always approx. l2V
l Neutral switch malfunction l Clutch switch malfunction l Short circuit in wiring from ECU terminal IV to neutral or clutch switch
l Neutral switch maifunctton l Clutch switch malfunction l Open circuit in wiring from ECU terminal IV to neutral or clutch swttch
l Poor connection at ECU connector
93GOFZ789
F2-63

CUNTRUL SYSTEM F2
Incorrect voltage Possible cause
I
Above Ok’ l Poor contact at ground terminal l Open crrcurt in wiring from ECU to ground
Always approx. OV or approx. 2V
l Refer to Code No.02 Troubleshooting -
Always approx. OV or approx. ISV - l Refer to Code No.03 Troubleshooting
Always OV
Always OV -
- -
-
l Refer to Code No.05 Troubleshooting
l . Short circutt in wiring from ECU termrnal 2K to throttle sensor, or airflow
meter
l Poor connection at ECU connector l ECU malfunctron
Below 4-W or above 5.5V
Always OV
l ECU malfunction
l Throttle sensor malfunction l Short circurt in wiring from ECU terminal 2L to throttle sensor l Poor connection at ECU connector
l ECU malfunction
Always approx. 5V
Always constant
Always above f V
OV after warm-up
Always approx. IV after warm-up . Throttle sensor m&adjustment
l Open circuit in wiring from ECU terminal 2L to throttle sensor l Open circuit in wiring from ECU terminal 2t to ECU terminal 20
l Open circuit in wiring from ECU terminal 2M to throttle sensor l Open circuit in wiring from ECU terminal 2K to throttle sensor l Open circuit in wiring from ECU terminal 2D to throttle sensor
l Throttle sensor m&adjustment
l Refer to Code No.15 Troubleshooting
l Refer to Code No.1 7 TroubleshootIng
Always OV or approx. 5V l Refer to Code No.08 Troubleshooting
-
Always OV or approx. 5V
Always OV or approx. 5V
l Refer to Code No.1 0 Troubleshootrng
1
l Refer to Code No.09 Troubfeshooting
Always OV . Indicator broken
l Open or short circuit rn wirinq from ECU 2R to rgnition swatch
F2-65

CONTROLSYSTEM F2
I
7
Incorrect voltage Possible cause
Always OV l Open or short circuit in wjring from ECU terminal 2s to buzzer
Always OV or approx. 12V
1 l Refer to Code No.25 Troubieshootlng
Always OV
1
l Marn relav (FUEL INJ relay) malfunction
/ l Open or shbrt circuit in wi&g from injector to ECU terminal 2U or 2V
Always approx. 12V
l ECU malfunctron
Always OV or approx. t2V
l Refer to Code No.34 TroubleshootIng
Always OV or approx. 12V
l Refer to Code No.26 Troubleshooting
Always OV
l Open or short circuit KI wiring from ECU terminal 2Y to relay
f2-67