MAZDA PROTEGE 1992 Workshop Manual

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

TROUBLESHOOTING GUIDE
27 MIL ALWAYS ON
DESCRIP- *Self-Diagnosis Checker does not indicate Malfunction Code No. but MIL always ON
TION
[TROUBLESHOOTING HINTS]
*Short circuit in wiring harness
l ECU malfunction
iTEF 1
1
-
s
Disconnect (Y/B) wire from ECU and check if
MIL goes off
‘YIB
ATX YIB
INSPECTION ACTION
Yes Replace ECU CT page F-149
No Check for short circuit in wiring be-
tween instrument cluster and ECU
23UOFX-042
28
MIL NEVER ON
IESCRIP- *Self-Diagnosis Checker indicates Malfunction Code No. of input device but MIL never ON
RON *Other indicator and warning lamps OK
:TROUBLESHOOTING HINTS]
b Bulb burned
‘Open circuit in wiring harness
m ECU malfunction
TEP INSPECTION
ACTION
1 Ground (Y/B) wire at ECU with jumper wire and
Yes Check connection of ECU connector
check if MIL comes on
MTX e If OK, replace ECU w page F-149
I- i -!~ !r--~r’:~;-‘;- --~_:- ,
1 i r 1 1 1 ;-.:,~;~$~& {-;&# ,$&]j 4 If not OK, repair ECU connector
! No
Check if bulb is OK
ATX 13 If OK, repair (Y/B) wire between
ECU and instrument cluster
e If not OK, replace bulb CT page T-83
23UOFX-043
29 A/C DOES NOT WORK
DESCRIP- *Blower fan operates but magnet clutch does not operate
TION
[TROUBLESHOOTING HINTS]
*Open or short circuit in wiring harness
*A/C relay, A/C switch, or magnetic clutch malfunction
l ECU malfunction
TEP/ INSPECTION ACTION
1 1 Check ECU
terminal 10 (MTX) 10 (ATX) voltage 1
Yes Check ECU terminal 1 J (MTX) 1 L (ATX)
OK
CT= page F-152
MTX
T7J++!;i”-
L
ATX
No voltage OK
CT page F-152
1-3 If OK, check A/C system
c3- page U-30
~3 If not OK, replace ECU CT page F-149
Check for cause w page F-153
F-77

F ENGINE TUNE-UP
ENGINE TUNE-UP
PREPARATlON
SST
I
I I
49 BO19 9AO
System Selector For
inspection of igni-
tion timing and
idle speed
hA ‘I
03UOFX-04
03UOFX-04
03UOFX-04
NG POINT
03UOFX-04 03UOFX-045
BASIC INSPECTION
Engine Oil
1. Remove the engine oil level gauge and check the engine
oil level and oil condition.
2. Add or change the oil as necessary.
Coolant
Warning
l Never remove the radiator cap while the engine is
hot.
l Wrap a thick cloth around the cap before carefully
removing it.
1. Remove the coolant level gauge from the coolant reservoir.
2. Check that the coolant level is between the L and F marks
of the gauge.
3. Add coolant if necessary.
Battery
1. Check for corrosion on the terminals and for loose cable
connections. If necessary, clean the clamps and tighten
them firmly.
2. Check that the electrolyte level is between the UPPER LEV-
EL and LOWER LEVEL marks.
3. Add distilled water if necessary.
4. Check the specific gravity with a hydrometer.
Gravity: 1.27-l .29 (at 20% [68OF] )

ENGINE TUNE-UP F
03UOFX.051
03UOFX-051
- w4TEN I
Air Cleaner Element
Inspection
1. Check the air cleaner element for excessive dirt, damage,
or oil.
Caution
l Do not use compression air to clean the element.
2. Replace the element if necessary.
ADJUSTMENT
Preparation
1. Warm up the engine to normal operating temperature.
2. Turn all electric loads OFF.
3. Connect the
SST to the diagnosis connector.
4. Connect a timing light.
5. Connect a tachometer to the diagnosis connector
IG- ter-
minal as shown.
6. Set switch @to position 1.
7. Set TEST SW to SELF-TEST.
Note
l If the SST is not used, jump across the TEN termi-
nal and the GND terminal of the diagnosis con-
nector.
Ignition Timing
1. Perform “Preparation”. (Refer to above.)
2. Check if the timing mark (yellow) on the crankshaft pulley
and the mark on the timing belt cover are aligned.
Specification:
Engine
Ignition Timing BTDC B6 BP SOHC BP DOHC
6O-8* 4O--6O go-110
SOHC DOHC
I 03UOFX-054
3. If the marks are not aligned, loosen the distributor lock bolts,
and turn the distributor to make the adjustment.
4. Tighten the distributor lock bolts to the specified torque.
Tightening torque:
19-25 N#m (1.9-2.6 m-kg, 14-19 ft-lb)
5. Disconnect the SST.
F-79

F ENGINE TUNE-UP
23UOFX-046 Note
l When the parking brake is not applied, the idle
speed for ATX model (Canada) is approx. 800 rpm. Idle Speed
1. Perform “Preparation”. (Refer to page F-79.)
2. Apply parking brake.
3. Check that the idle speed is within specification.
Idle speed (Neutral or P range): 700-800 rpm
Caution
l Check the idle speed without the electric cooling
fan operating.
4. If not within the specification, adjust the idle by turning the
air adjusting screw.
5. Disconnect the SST.
F-80

ENGINE TUNE-UP F
MEMO
F-81

F SELF-DIAGNOSIS FUNCTION
SELF-DIAGNOSIS FUNCTION
DESCRIPTION
The engine control unit (integrated with the EC-AT control unit) has built-in Self-Diagnosis function the same
as for the previous models. When trouble occurs in the main input devices or output devices, they are indi-
cated and retrieved from the engine control unit (ECU) as service code numbers.
When inspecting for service code(s) memorized in the ECU use the Self-Diagnosis checker and system selector
(SST).
Note
l The ECU constantly checks for malfunction of the in put devices. But, the ECU checks for
malfunction of output devices only in a three second period after the ignition switch is turned
ON and the TEN terminal of the diagnosis connector is grounded.
-
-
INPUT =
SIGNALS-
-
-
- SELF-
DIAGNOSTIC
L!
I-
FUNCTION ENGINE CONTROL
UNIT
j FAIL-SAFE
FUNCTION
I
SYSTEM SELF-DIAGNOSIS
SELECTOR
CHECKER
MIL
(MALFUNCTION
INDICATOR LAMP)

SELF-DIAGNOSIS FUNCTION F
PREPARATION
SST
49 6019 9AO
System Selector For
diagnosis 49 HO18 9Al
Self-Diagnosis
Checker For
diagnosis
SERVICE CODE NUMBER
Inspection Procedure
1. Connect the SST to the diagnosis connector.
2. Set switch @to position 1.
3. Set TEST SW to SELF-TEST position.
23UOFX-048
03UOFX.059
I
4. Connect the SST to the System Selector and a ground
5. Set the select switch to position A.
6. Turn the ignition switch to ON.
7. Verify that 88 flashes on the digital display and the buzzer
sounds for 3 sec. after turning the ignition switch ON.
8. If 88 does not flash, check the main relay (FUEL INJ relay)
(Refer to page F-172) power supply circuit, and diagno-
sis connector wiring.
9. If 88 flashes and the buzzer sounds continuously for more
than 20 sec., check for a short circuit between the engine
control unit terminal 1 F and the diagnosis connector. Re-
place the engine control unit if necessary and perform Steps
3 and 7 again.
23UOFX-049 IO. Note any code numbers and check for the causes by refer-
ring to the check sequences shown on pages F-88
through F-103. Repair as necessary.
Note
l Cancel the code numbers by performing the after-
repair procedure following repairs.
(Refer to page F-104.)
I 23UOFX-050
F--83

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