ECU MAZDA PROTEGE 1992 Repair Manual

TROUBLESHOOTING GUIDE
TEP INSPECTION
ACTION
7 Check for correct fuel line pressure at idle Yes Check if fuel line pressure decreases w page F-129 when accelerating quickly Fuel line pressure:
c3 If decreases, check fuel line and fil- 265-314 kPa (2.7-3.2 kg/cm’, 38-46 psi) ter for clogging (Vacuum hose to pressure regulator dis- *
If no decrease, go to next step connected)
INSTALL CLAMPS No Low pressure
Check fuel line pressure while pinching
fuel return hose
+ If fuel line pressure quickly in-
creases, check pressure regulator w page F-129
+ If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
regulator
If not clogged, check fuel pump .*
maximum pressure w page F-126
8 Connect System Selector to diagnosis connector Yes Check if ignition timing advances when
and set Test Switch to “SELF TEST” and check accelerating
for correct ignition timing at idle after warm-up w page F-79
c3 If advances, go to next step
c3 If not advance, replace ECU w page F-149
Ignition timing (BTDC)
l BP DOHC : go-1 1 o l BP SOHC : 4’-8’
l B6 : 6O--8O No Adjust w page F-79
9
Check if air duct and air hoses are correctly Yes Go to next step
installed w page F-109
No
Repair
10 Check if exhaust system is restricted Yes Repair or replace w page F-136
No SOHC
Go to Step 12 DOHC
Go to next step
11 Check if variable inertia control system (VICS) is
Yes Go to next step
OK w page F-118
No
Repair or replace
12 Try known good ECU and check if condition
improves w page F-149
-’
F-58

TROUBLESHOOTING GUIDE
18 SURGES WHILE CRUISING
DESCRIP- *Unexpected change in engine speed which is usually repetitive
TION [TROUBLESHOOTING HINTS]
@ Air/Fuel mixture too lean
@ Misfire
3 Poor connection in wiring harness
SYSTEM SELECT:
1 “88” flashes
Check ECU terminal 1F voltage CT= page F-150
Specification: Battery voltage
(Ignition switch ON)
+ If OK, replace ECU w page F-149 4 If not OK, check wiring between
ECU and Self-Diagnosis Checker
check sequence) w page F-106
heck ECU terminal ID voltage CT page F-150
oxygen sensor
F-59

F TROUBLESHOOTING GUIDE
TEP INSPECTION ACTION
6 Check if throttle linkage is correctly installed and Yes Go to next step
operates freely
w page F-l 14
No Correct, clean, or replace as required
any binding or damaged linkage, and
adjust cable deflection at throttle body CT page F-l 12
7 Check for correct intake manifold vacuum at idle Yes Go to next step
Vacuum: More than 450 mmHg (17.7 intig) -
No
Check for air leakage of intake air sys-
tem components
8 Check if air cleaner element is clean Yes Go to next step
w page F-79
No Replace air cleaner element
9 Connect System Selector to diagnosis connector Yes Check if ignition timing advances when
and set Test Switch to “SELF TEST” and check accelerating
for correct ignition timing at idle after warm-up
w page F-79 c3 If advances, go to next step
c3 If not advance, replace ECU [II page F-149
Ignition timing (BTDC)
l BP DOHC : Q”-1 1 o l BP SOHC : 4O-6’
’ B6 : 6O-8O
No Adjust CT+ page F-79
10 Check for correct fuel line pressure at idle Yes Check if fuel line pressure decreases
w page F-129 when accelerating quickly
Fuel line pressure: c3 If decreases, check for fuel pump
265-314 kPa (2.7-3.2 kg/cm*, 38-46 psi) maximum pressure w page F-126
(Vacuum hose to pressure regulator dis- If OK, check fuel line and filter for
connected) clogging CI,’ page F-122
+ If no decrease, go to next step
-
No Low pressure
Check fuel line pressure by pinching
fuel return hose
cti If fuel line pressure quickly In-
creases, check pressure regulator CT page F-129
ti If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
regulator
If not clogged, check fuel pump
maximum pressure cr page F-126
-
High pressure
Check if fuel return line is clogged
Q If OK, replace pressure regulator C-Y- page F-130
+ If not OK, replace
--_I. 1”1-~~-~~
11 Check if exhaust system is restricted Yes Repair or replace
C-T- page F-136
No Go to next step
12 Try known good ECU and check if condition
improves
CT page F-149
23UOFX-034
F-60

TROUBLESHOOTING GUIDE F
9 LACK OF POWER
_-- --
L L -
ESCRIP- *Performance poor under load when throttle valve wide open
ION *Reduced maximum speed
* Idle condition normal
VtOUBLESHOOTlNG HINTS]
) Factors other than engine malfunction
*Clutch slipping
* ATX slipping
l Brake dragging l Low tire pressure
l Incorrect We size l Overloaded
‘, Low intake air amount @ Air/Fuel mixture too lean
l Fuel line pressure decreases l Fuel injection malfunction
@ Poor ignition
@ Low engine compression
@ Alcohol blended fuel used
l Throttle valve not open fully
*Clogged intake air system
l Low tire pressure CY Section H
CY Section K
cz7 Section P
c7 Section Q
w page F-l 14
CT= page F-l 12
Checker with ignition switch ON
w page F-83
rminal 1F voltage CT page F-150
Specification: Battery voltage
(Ignition switch ON)
* If OK, replace ECU w page F-149
c3 If not OK, check wiring between
ECU and Self-Diagnosis Checker
Ignition timing (BTDC)
l BP DOHC : 9*-l lo l BP SOHC
: 4O-8O 4 If advances, go to next step
* If not advance, check ECU terminal
w page F-150
F-61

TROUBLESHOOTING GUIDE
ISTEP 1 INSPECTION
15 Check if variable inertia charging system (WCS)
is OK (BPD) CT page F-l 18
16 Try known good ECU and check if condition
improves w page F-149
1
23UOFX-035
F-64

TROUBLESHOOTING GUIDE F
20 POOR ACCELERATION
DESCRIP- l Performance poor while accelerating
TION l idle condition normal [TROUBLESHOOTING HINTS)
3 Factors other than engine malfunction @ Air/Fuel mixture too lean
*Clutch slipping l Fuel line pressure decreases l ATX slipping l Fuel injection malfunction
l Brake dragging @ Poor ignition l Low tire pressure
@ Low engine compression
l Incorrect tire size @ Alcohol blended fuel used l Over-loaded
3 Low intake arr amount
*Throttle valve not open fully
*Clogging in intake air system
Check factors other than engine CT Section H
c7 Section
P
ing accelerator fully w page F-l 14
w page F-l 12
Checker with ignition switch ON w page F-83
rminal 1 F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
W: SELF TEST c3 If OK, replace ECU w page F-149 r;3 If not OK, check wiring between
ECU and Self-Diagnosis Checker
Clearance between throttle
lever and stopper
0.1 mm (0.004 in)
l.Omm (0.039 in)
O.lmm (0.004 in)
0.6mm (0.024 in)

iTEP INSPECTION ACTION
5 Connect System Selector to diagnosis connector Yes
and set Test Switch to “SELF TEST” and check Check if ignition timing advances when
for correct ignition timing at idle after warm-up accelerating w page F-79
* If advances, go to next step
r3 If not advance, check ECU terminal Ignition timing (BTDC)
voltages l BP DOHC : go--ll” w page F-150 l BP SOHC : 4O-6O
. B6 : 6O-6O
No
Adjust w page F-79
6
Check if ECU terminal voltages are OK
Yes Go to next step w page F-150
No
Check for cause ~7 page F-151
7
Check for correct intake manifold vacuum at idle
Yes Go to next step Intake manifold vacuum:
More than 450 mmHg (17.7 inHg) No
Check for air leakage of intake air sys-
tem components
8 Check for correct fuel line pressure at idle
Yes Check if fuel line pressure decreases w page F-129
when accelerating quickly Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm’, 39-46 psi)
(Vacuum hose to pressure regulator dls-
connected)
d If decreases, check fuel pump
maximum pressure (3‘ page F-126
If OK, check fuel line and filter for
clogging
* If not decrease, go to next step
No Low pressure
Check for fuel line pressure while pinch-
ing fuel return hose
c3 If fuel line pressure quickly in-
creases, check pressure regulator w page F-129
+ If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
regulator
If not clogged, check fuel pump
maximum pressure w page F-126
High pressure
Check if fuel line is clogged
* If OK, replace pressure regulator w page F-130
c3 If not OK, replace
F-66

F TROUBLESHOOTING GUIDE
iTEF
___
13
14
-
15
__
16 INSPECTION
Change fuel and check if acceleration improves
Check if A/C cut-off control system is OK
Check if variable inertia charging system (WCS)
is OK (BPD)
w page F-l 18
Try known good ECU and check if condition
improves
w page F-149 ACTION
Yes Change fuel to another brand
No Go to next step
Yes SOHC
Go to Step 16
DOHC
Go to next step
No Repair or replace
Yes Go to next step
I
No 1 Repair or replace /
F-68

TROUBLESHOOTING GUIDE F
21 RUNS ROUGH ON DECELERATION/BACKFIRE
IESCRIP.
*Engine runs rough while decelerating and abnormal combustion occurs in exhaust system
MON l Transaxle in normal condition TROUBLESHOOTING HINTS]
1) Arr/Fuel mixture too rich
l Arr cleaner element clogged
l Fuel injection control malfunctron
(Fuel cut control)
l Injector fuel leakage
*Throttle sensor (IDL terminal) malfunction
l Dashpot malfunctron
er with ignition switch ON
Check ECU terminal 1F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
+ If OK, replace ECU w page F-149 6 If not OK, check wiring between
ECU and Self-Diagnosis Checker
----~
Check for cause (Refer to specified
check sequence) w page F-106
SELECT SW: A Vacuum: More than 450 mmHg (17.7 inHg)
tern components
4 Check if air cleaner element is clean Yes
Go to next step w page F-79
No
Replace air cleaner element
5 Check if ECU terminal voltages are OK
Yes Go to next step
MTX...Especially lN, 2A, 2U and 2V
ATX... Especially lT, 3A, 3U and 3V CT page F-150
No Check for cause c=i‘ page F-151
F-69

F TROUBLESHOOTING GUIDE
r TEP INSPECTION
ACTION
6 Check if fuel cut operation is OK
Yes Go to next step
CT page F-143
No Try known good ECU and check if con-
dition improves
w page F-149
7 Check if airflow meter is OK
Yes Go to next step
w page F-166
I. Check if measuring plate moves smoothly
II. Check resistance No Repair or replace
8 Check if throttle sensor IDL terminal is OK
Yes Go to next step
w page F-169
No Adjust CT page F-169
9 Check if dashpot is correctly adjusted
Yes Check if throttle valve is contaminated
w page F-142
+ If contaminated, clean throttle body
Dashpot set speed: * If not contaminated, replace throttle
E”P . . . . . . . ..*.*....................
Approx. 3,000 rpm body
SOHC . . . . . . . . . . . . . . . . . . . . . .
Approx. 2,700 rpm
BP DOHC . . . . . . . . . . . . . . . . . . . . . . Approx. 3,600 rpm
No Adjust w page F-142
IO Check injector for fuel leakage
Yes Replace
w page F-132
No Go to next step
11 Try known good ECU and check if condition
improves
w page F-149
23UOFX-037
F-70