1992 MAZDA PROTEGE fuel pressure

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

22 KNOCKING
DESCRIP- *Abnormal combustion accompanied by audible “pinging” noise
I-ION
[TROUBLESHOOTING HINTS]
3 Incorrect ignition timing (Too advanced)
@ Air/Fuel mixture too lean
3 Carbon deposits in cylinder
*Fuel injection amount not correct
3 Overheating
l Fuel line pressure decreases while accelerating
TEP INSPECTION
ACTION
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
CT page F-79
Ignition timing (BTDC)
l BP DOHC : go-1 1 o l BP SOHC : 4”-6O
’ B6 No
Adjust a page F-79
2 Check if “00” is displayed on Self-Diagnosis
Yes Go to next step
Checker with ignition switch ON
W page F-62
No
Service Code No. displayed
Check for cause (Refer to specified
check sequence) w page F-63
“88” flashes
Check ECU terminal 1F voltage CT page F-150
Specification: Battery voltage
(Ignition switch ON)
c3 If OK, replace ECU w page F-149
W: SELF TEST c3 If not OK, check wiring between
ECU and Self-Diagnosis Checker
3 Check for correct intake manifold vacuum at idle
Yes Go to next step
VaCUUm: More than 450 mmHg (17.7 inHg) No
Check for air leakage of intake air sys-
tem components
4
Check for correct engine compression
Yes Go to next step
w page Bl-10
B2-10
Engine compression (Minimum):
l BP DOHC
883 kPa (9.0 kg/cm’, 128 psi)-300 rpm
l BP SOHC
834 kPa (8.5 kg/cm*, 121 psi)300 rpm
l B6
932 kPa (9.5 kg/cm’, 135 psi)300 rpm No High compression
Check engine condition CI page 81-10
62-l 0 l Carbon deposits
F-71

F TROUBLESHOOTING GUIDE
STEP INSPECTION ACTION
5 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: + If it decreases, check for clogging
265-314 kPa (2.7-3.2 kg/cm’, 36-46 psi) between fuel pump and pressure
(Vacuum hose to pressure regulator dis- regulator
connected) * If not decrease, go to next step
INSTALL CLAMPS No Low pressure
Check fuel line pressure while pinching
fuel return hose
c3 If fuel line pressure quickly in-
creases, check pressure regulator w page F-129
c3 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
6 Check if cooling system is OK Yes Go to next step
w page E-13
No Repair or replace
l Thermostat w page E-9
l Electric cooling fan w page E-16 l Radiator w page E-6
7 Try known good ECU and check if condition Yes Replace ECU CT page F-149
improves
CT= page F-149 No
Change fuel to another brand or use
higher octane fuel
23lJOFX.0: .-._ ,
F-72

F TROUBLESHOOTING GUIDE
I 24 I EXHAUST SULFUR SMELL I
DESCRIP-
l Exhaust gas smells abnormally
TION
[TROUBLESHOOTING HINTS]
High sulfur content fuel used
STEP INSPECTION
1
Change fuel to another brand ACTION
03UOFX-039
25 HIGH OIL CONSUMPTION
DESCRIP-
l Oil consumption excessive
TION
[TROUBLESHOOTING HINTS]
@ PCV system malfunction
@ Engine malfunction (Oil working up, working down, or leakage)
iTEP
INSPECTION
1 Check if PCV hose, ventilation hose or their at- Yes Repair or replace
taching nipples are separated, damaged,
clogged, or restricted
w page F-138 No Go to next step
2 Check if air pressure or oil is present at ventila- Yes Go to next step
tion hose ACTION
No Check engine condition w page 81-3
82-3
l Oil leakage
*Worn valve seal
*Worn valve stem
*Worn valve guide
3 Check if vacuum is felt at PCV valve at idle Yes Check engine condition w page 91-3
w page F-138 82-3
*Worn piston ring groove
*Stuck piston rings l
Worn piston or cylinder
No Replace PCV valve
23UOFX-040 /-.
F-74

TROUBLESHOOTING GUIDE F
26 POOR FUEL ECONOMY
DESCRIP-
l Fuel economy unsatisfactory TION
[TROUBLESHOOTING HINTS]
While fuel consumption is drastically increased by city driving, short-run operation, stop and go driving, extended winter
warm-up periods, etc., as opposed to “trip” mileage, an attempt should be made to determine these factors when con-
fronted with “poor mileage” conditions. However, since the operator is not always at fault, the following is offered.
@II Operator depressing accelerator more than usual due to
@ Air/Fuel mixture too rich
low engine power
l Poor ignition *High fuel line pressure
@ Alcohol blended fuel used
*Low intake air amount
l Electronic spark advance control system malfunction @ High vehicle load l Low tire pressure
*Clutch slipping/ATX slipping l Incorrect tire size l Exhaust component restricted l Brake dragging ;TEP
INSPECTION ACTION
1
Check factors other than engine Yes
Go to next step
l Low tire pressure = Section Q 9 Unrecommended tire srze v Section Q l Clutch slipping w Section H l Brake dragging No
0 Section P Repair
l Exhaust component restricted cz= page F-136
2
Check if air hoses are connected correctly - Yes
Go to next step CI page F-109
No
Repair 3
Check if “00” IS displayed on Self-Diagnosis
Yes
Checker with ignition switch ON Go to next step W page F-82 No
SYSTEM SELECT: 1 Service Code No. displayed Check for cause (Refer to specified
check sequence) w page F-63
“88” flashes
Check ECU terminal 1F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
* If OK, replace ECU CT= page F-149 e If not OK, check wiring between
ECU and Self-Diagnosis Checker 4
Check for correct intake manifold vacuum at idle
Yes Go to next step Vacuum: More than 450 mmHg (17.7 inHg) No
Check for air leakage at intake air sys-
tem components 5
Check if air cleaner element is clean Yes
Go to next step CT= page F-79
No
Replace air cleaner element
F-75

F TROUBLESHOOTING GUIDE
s
-
Ignition timing (BTDC) l BP DOHC : Q”-11 o l BP SOHC : 4O-6“
Fuel line pressure:
216-265 kPa (2.2-2.7 kg/cm*, 31-36 psi)
INSTALL CLAMPS
hose to pressure
ged or poorly con-
c3 If OK, replace pressure regulator w page F-130
c3 If not OK, repair or replace hose
Fuel line pressure: More than 147 kPa
(1.5 kg/cm*, 21 psi) for 5 min.
INSTALL CLAMPS
23UOFX-041
F-76

F SELF-DIAGNOSIS FUNCTION
Troubleshooting
If a service code number is shown on the SST, check for the cause by using the chart related to the code
number shown.
Service code number
CODE LOCATION OF
NO.
MALFUNCTION OUTPUT SIGNAL PATTERN
SELF-DIAGNOSIS FAIL-SAFE
02
Ne-signal
:E nl-u No Ne-signal
-
03 G-signal
(DOHC) No G-signal Cancels 2-group
injection
06* Vehicle speed
sensor ON
OFF No input signal from Shifting performed
vehicle speed normally
sensor
08 Airflow meter ON
OFF Open or short circuit Basic fuel injection
amount fixed as for two
driving modes
(1) Idle switch ON
(2) Idle switch OFF
09 Water
thermosensor ON
OFF Maintains constant 20%
(68OF) command
10 Intake air
thermosensor Maintains constant 20°C
(68OF) command
12
Throttle sensor
“,E l--uL-l Throttle opening judged
as full stroke lockup not
provided
Atmospheric ON Maintains constant
14 pressure sensor command of sea level
(in ECU)
OFF pressure
15 Oxygen sensor
(inactivation) ON
OFF Sensor output
continues less than
0.55V 95 sec. after
engine starts
(1500 rpm) Cancels engine feedback
operation
Oxygen sensor ON Sensor output Cancels engine feedback
17
(Inversion) continues uncharged operatron
OFF 50 sec. after engine
exceeds 1500 rpm
Solenoid valve ON
25 (pressure
regulator)
OFF u 1 nnluln Open or short crrcurt
“If the marked code numbers appeor, refer to Section K
F-84

SELF-DIAGNOSIS FUNCTION
:ODE No. 17 (Oxygen sensor-lnvarsion)
r t
INSPECTION
Check if same Code No. is present after per-
forming after-repair procedure CT- page F-704
Check monitor lamp of Self-Diagnosis Checker il-
luminate at idle after warming-up engine and
running it at 2,500-3,000 rpm
for 3 minutes
Check for correct fuel line pressure at idle CT page F-129
Fuel line pressure;
265-314 kPa (2.7-3.2 kg/cm2, 38-46 psi)
{Vacuum hose to pressure regulator
disconnected)
4 Check injectors for fuel teakage c3 page F-132
5
Disconnect each high-tension lead at idle and
check if engine speed decreases equally at each
cylinder
Circuit Oiagram
MTX
I ACTION
Yes 1 Go to next step NO
Check oxygen sensor circuit for poor
connection
r3 If OK, perform troubleshooting
Code No.15
a
If not OK, repair or replace con-
nector u page F-98
Yes Go to next step Note
l A/F mixture rich
No
I Go to Step 5 Note
l A/F mixture is lean or misfire
occurring
Yes
I Go to next step No High pressure
Check if fuel return hose is ciogged or
restricted
+ If OK, replace pressure regulator CT page F-130
c3 If not OK, repair or replace
Yes Replace injector
No Check if water thermosensor is OK
ti if OK, Go to Step 11
c3 If not OK, replace water thermo-
sensor c7 page F-168
CT page F-168
Yes
Go to next step No
Go to Step 8
23UOFX-07
OXYGEN SENSOR
I
R/L
ECU
----------h--M
23UOFX-074
F-l 00