fuel pressure MAZDA PROTEGE 1992 Owner's Manual

TROUBLESHOOTING GUIDE F
1TEP INSPECTION
ACTION
7 Connect diagnosis connector terminals F/P and Yes
Go to next step
GND with jumper wire and check for correct fuel
line pressure with ignition switch ON w page F-122
No Low pressure
Check fuel line pressure while pinching Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm*, 38-46 psi) 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 fuel line for clog-
ging between fuel pump and
pressure regulator
If not clogged, check fuel pump
maximum pressure High pressure w page F-126
Check if fuel return hose is clogged or
restricted
INSTALL CLAMPS c3 If OK, replace pressure regulator w page F-130 c3 If not OK, repair or replace hose
8
Try known good ECU and check if condition
Yes Replace ECU w page F-149
improves w page F-149 No
Change fuel to another brand
23UOFX-02
F-39

F TROUBLESHOOTING GUIDE
7 CRANKS NORMALLY BUT HARD TO START - AFTER WARM-UP
*Engine cranks at normal speed but requires excessive cranking time before starting after running and hot
DESCRIP- soaked
TION *Battery in normal condition
*Engine starts normally when cold
*Engine runs normally at idle [If idle condition not OK, refer to “Rough idle” (Nos. 8-12)] [TROUBLESHOOTING HINTS]
3 Air/Fuel mixture too rich
@ Vapor lock l Fuel injection control malfunction
*Fuel pressure not held in fuel line after engine stopped l Injector fuel leakage
*High RVP (winter) fuel used in warm weather
l Pressure regulator control system malfunction [BP] w page F-150
Specification: Battery voltage
(Ignition switch ON)
W: SELF TEST c3 If OK, replace ECU w page F-149 * If not OK, check wiring between CT- page F-134
Fuel line pressure: More than 147 kPa
(1.5 kg/cm*, 21 psi) for 5 min. w page F-130
+ If OK, replace pressure regulator CT- page F-130
c3 If not OK, check fuel pump hold w page F-125
If fuel pump is OK, check injectors
for fuel leakage (3 page F-132
F-40

F TROUBLESHOOTING GUIDE
8 ROUGH IDLE/ENGINE STALLS AT IDLE - ALWAYS
bESCRIP- l Engine starts normally but stalls or vibrates excessively at idle in every condition
‘ION TROUBLESHOOTING HINTS]
D Air/Fuel mixture too lean @ Incorrect idle speed
l Air leakage l Idle speed misadjustment l Fuel injection control malfunction l Idle speed control malfunction
*Low fuel line pressure @ One or more spark plugs not firing
3 One or more injectors clogged or not operating @ Low engine compression
3 Low intake air amount @ Airflow meter stuck INSPECTION
1
1
2
3
4
5
6
- Check if “00” is displayed on Self-Diagnosis
Checker with ignition switch ON w page F-82
SYSTEM2ELECT: 1
M v’SELECT SW: A TEST
Check if ECU terminal voltages are OK
MTX...Especially 2D, 20 and 2Q
ATX... Especially 2B, 2E and 3D CT page F-150
Disconnect high-tension lead at idle and check if
engine speed decreases equally at each cylinder
Check for injector operating sound at idle
Check if battery voltage exists at injector connec-
tor (W/R) wire
Check if strong blue spark is visible at discon-
nected high-tension lead
, Yes No Service Code No. displayed
Check for cause (Refer to specified
:heck sequence) “88” flashes
Check ECU terminal IF voltage CT page F-150
Specification: Battery voltage
(Ignition switch ON)
3 If OK, replace ECU w page F-149 3 If not OK, check wiring between
ECU and Self-Diaanosis Checker Yes
Go to next step No
Check for cause Yes
Go to Step 8 No
Go to next step
Go to Step 6
Go to Step 5 Yes
No
Yes
No
Yes
No I-
30 to next step w page F-83
0 page F-151
Check if injector resistance is OK c7 page F-131
Resistance: Approx. 12-l 852
c3 If OK, check wiring between ECU
and injector
c3 If not OK, replace injector w page F-131
Check wiring between ECU and injector
Go to next step
Check high-tension lead w page G-17
Q If OK, check distributor cap and
rotor w page G-22
c3 If not OK, replace high-tension lead
F-42

TROUBLESHOOTING GUIDE F
WEAR AND CA
DAMAGE AND
DETERIORATION
r;f> If OK, replace injector
=D If not OK, check for cause w page F-131
u page Bl-10
82-l 0
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm2, 38-48 psi) fuel line pressure while pinching
* If fuel line pressure quickly in-
creases, check pressure regulator L-Y page F-129
~3 If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
maximum pressure
CT page F-126
airflow meter moves smoot
_, .’
No Go to next step
I1
Check for correct engine compression
Yes Go to next step
CI page 81-10
82-l 0
Engine compression (Minimum):
l BP SOHC
834 kPa (8.5 kg/cm*, 121 psi)300 rpm
l BP DOHC
883 kPa (9.0 kg/cm*, 128 psi)-300 rpm
l B6 No Check for cause
CT page 81-10
82-l 0
932 kPa (9.5 kg/cm*, 135 psi)-300 rpm
I2 Connect System Selector to diagnosis connector
Yes Try known good ECU and check if con-
and set Test Switch to “SELF TEST” and check
dition improves
CT page F-149
for correct ignition timing at idle after warm-up
CT page F-79
Ignition timing (BTDC)
BP DOHC : Q”-ll”
BP SOHC : 4O-6O
B6
: 6”--8* No Adjust ignition timing
a- page F-79
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F-43

F TROUBLESHOOTING GUIDE
10
ROUGH IDLE/ENGINE STALLS AT IDLE - AFTER WARM-UP
DESCRIP-
rlON
*Engine runs normally at idle during warm-up but engine stalls or vibrates excessively after warm-up [TROUBLESHOOTING HINTS]
3 Idle speed control system malfunction @ Air/Fuel mixture too rich
3 Air/Fuel mixture too lean l Fuel injection control malfunction l Air leakage (Correction for coolant temperature)
*Low fuel line pressure @ Poor ignition
@ Low engine compression CT= page F-83
Check ECU terminal 1F voltage CT page F-150
Specification: Battery voltage
(Ignition switch ON)
* If OK, replace ECU w page F-149 * If not OK, check wiring between
ECU and Self-Diagnosis Checker
Check for cause LY page F-151
Vacuum: More than 450 mmHg (17.7 inHg)
I.:.F page F-109
F-46

TROUBLESHOOTING GUIDE F
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm’, 36-46 psi)
(Vacuum hose to pressure regulator Ine pressure while pinching
d If fuel line pressure quickly in-
creases, check pressure regulator w page F-129
* If fuel line pressure gradually in-
If not clogged, check fuel pump
maximum pressure w page F-126
Ignition timing (BTDC)
l BP DOHC : go-1 1 o l BP SOHC : 4”-6O
Resistance: 12-l 60
eck wiring between ECU
Engine compression (Minimum):
l BP SOHC :
634 kPa (6.5 kg/cm2, 121 psi)900 rpm
check distributor cap and
23UOFX-02
F-47

TROUBLESHOOTING GUIDE
17 HESITATES/STUMBLES ON ACCELERATION
bESCRIP-
*Flat spot occurs just after accelerator depressed or mild jerking occurs during acceleration
‘ION TROUBLESHOOTING HINTS]
0 Air/Fuel mixture becomes lean when depressing accelerator l Fuel injection control malfunction
(Correction for accelerating condition)
*Air leakage
l Fuel line pressure decreases l Spark advance control malfunction TEP INSPECTION ACTION
1 Check if “00” is displayed on Self-Diagnosis Yes Go to next step
Checker with ignition switch ON W page F-82 ’ No
Service Code No. displayed
SYSTEM SELECT: 1 Check for cause (Refer to specified
check sequence) w page F-83
“88” flashes
W: SELF TEST Check ECU terminal IF voltage CT= page F-150
Specification: Battery voltage
(Ignition switch ON) c3 If OK, replace ECU c? page F-149 * If not OK, check wiring between
ECU and Self-Diagnosis Checker Vacuum: More than 450 mmHg (17.7 InHg)
tern components
Replace air cleaner element 4
Check if ECU terminal voltages are OK
Yes Go to next step
MTX...Especiaily 2L
ATX... Especially lT, 2F, and 21 w page F-150
No Check for cause cp page F-151
5
Check if throttle linkage is correctly installed and
Yes Go to next step
operates freely w page F-l 14 ~~
Correct, clean, or replace as required
any binding or damaged linkage and
adjust cable deflection at throttle body w page F-l 14
6
Check continuity between throttle sensor termi- Yes Go to next step
nals IDL and E w page F-189
MTX
A-I-X 1
J E
IDL
Clearance between throttle
lever and stopper Continuity
MTX 0.1 mm (0.004 in) Yes
1 .Omm (0.039 in) No
ATX 0.1 mm (0.004 in)
Yes
0.6mm (0.024 in) No
No Adjust w page F-189
F-57

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

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