13-I 04 FUEL SYSTEM
the vacuum hose from the fuel pressure
regulator, and then measure the fuel pressure while using a
finger to plug the end of the hose.
Standard value:
330-370 kPa (47-53 psi) at curb idle
speed
(11)Check to be sure that the fuel pressure during idling does
not decrease even after the engine is raced a few times.
(12)&e a finger to gently press the fuel return hose while
repeatedly racing the engine, and check to be sure that
there is fuel pressure in the return hose also.
NOTE
There will be no fuel pressure in the return hose if there is
insufficient fuel flow.
(13)lf the fuel pressure measured in steps (9) to (12) deviates
from the standard value range, check for the probable
cause by referring to the table below, and then make the
appropriate repair.
Condition Probable causeRemedy
. Fuel pressure IS too low. Fuel filter is clogged.Replace the fuel filter.
. Fuel pressure drops during racing.. No fuel pressure In fuel return hose. Malfunction of the valve seat with-Replace the fuel pressure regula-in the fuel pressure regulator, ortor.
fuel leakage to return side caused by spring deterioration.
Fuel pump low discharge pressure.Replace the fuel pump.
Fuel pressure is too
highThe valve within the fuel pressure Replace the fuel pressure regula-regulator is sticking.
tor.
Clogging of the fuel return hose Clean or replace the hose and/or
and/or the pipe.pipe.
No change of the fuel pressure when Damaged vacuum hose or nippleReplace the vacuum hose, or clean
vacuum hose IS connected and when not clogging.the nipple.connected.
(14)Stop the engine and check for a change of the value
indicated by the fuel pressure gauge. The condition is
normal if there is no decrease of the indicated value within
two minutes. If there is a decrease of the indicated value, monitor the
speed of the decrease, and, referring to the table below.
determine the cause of the problem and make the
appropriate repair.
Condition Probable cause
After the engine is stopped, the fuel Injector leakage
pressure drops graudally.
Remedy
Replace the injector.
Leakage at the fuel pressure reg-
Replace the fuel pressure regula-
ulator valve seat tor.
There IS a sudden sharp drop of the fuel The check valve
(within the fuel Replace the fuel pump.
pressure immediately after the engine is pump) is not closed.
stopped.
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13-106
FUEL SYSTEM
TERMINAL VOLTAGE CHECK CHART
Terminal arrangement of engine control module connector NflTF
01 LO838
. .- -B+: Battery positive voltage
Terminal
No.Check condition (Engine state)StandardvalueRemarksCheck item
103
Backup power supply lgnitron
switch: OFF
102Power supply ignition switch: ONB+
107
109
Fuel pump dnve signal
Engine: Cranking 8V or higher
Engine: Idling
B+I
Ignition switch: ON
Engine:
ldlrng
Ignition switch: ON
Engine: idling
Engine speed: 2,000 rpm
B+I
o-3v
4.5- 5.5v
2.2- 3.2V
56
23
10
Multiport fuel
injection relay
(Fuel pump)
Sensor
rmpressecvoltage
Volume air flow
sensor
Air intake
temperature sensor Ignition
Air intake temperature of
0°C (32°F)switch:ONAir Intake temperature of 20°C (68°F); ji/
Air Intake temperature of 40°C (104°F)1.5-2.1V
Air intake temperature of 80°C (176’F)0.4- 1 .OV
Barometric
pressure sensor
Ignition
Altitude of 0 m (0 ft.)3.7-4.3vswitch:ON Altitude
of 1,200 m (3,937 ft.)3.2-3.av
Engrne coolant lgnitron
Coolant temperature of 0°C (32°F)3.2-3.Wtemperature switch: -sensorONCoolant temperature of 20°C (68°F)2.3-2.9v
1 Coolant temperature of 40°C
(104°F) 1 1.3- 1.9V(
) Coolant temperature of 80°C
(176’F)
1 0.3-0.9V
Throttle posrtionsensor Ignition swatch: It
Set the throttle valve to the
is kept ON for 15
seconds or more
Closed throttle position switchII
I
I
-
Ignition Set the throttle valve to the idlingo-1vswitch:position.3NSlightly open the throttle valve. 4V
or higher
3
16
!O
9
1 TSB Revision1
FUEL SYSTEM
TerminalCheck ItemCheck condition
(Engine state)StandardNo.valueRemarks
22
Camshaft position Engine: Cranking0.2 - 3.ov
sensor
Engrne: ldllng
21Crankshaft position Engine: Crankingsensor
Engine: Idling0.2 - 3.ov
108
104
18
lgnrtron switch-ST Engine: Cranking 8V
or higher
Park/neutral Ignition
Set the selector lever to
P or N.o-3v
position switch switch
:
ONSet the selector lever to D, 2, L or R.8- 14V
Vehicle speed
l Ignition switch: ON
sensor l Slowly run the vehicle forwardkeFaF:hevariation.)
Power steering
pressure switch
;;ir;z;ditioning
Engine:Steering wheel idle state
Idling opera-
tion after
warming-up During steering wheel operation
Engrne:Turn OFF the air conditioning switch.
Idling
Turn ON the air conditioning switch.(The air conditioning compressor is in
the drive state.)
B+
o-3v
o-3v
B+
35
1
51
52
50
51
54
Air conditioning
compressor
clutch relay
Oxygen sensor
No.
1 Injector
No. 2 Injector
No. 3 Injector
No. 4 Injector Ignition power
transistor unit l Engine: Idling
B+ or
l Air conditioning switch: OFF-ON temporarily
(The air conditioning compressor is in the 6V or
higher
drive state.)o’- 3v
Engine: Keep the engine speed at 2,000 rpm
after warming up. kQatot8h2:
(For checking, use a digital voltmeter.) variation.)
Engine: After warming up, rapidly press the
Voltage
accelerator pedal from the idling state. temporarily
drops slightly
from
14V to1 IV.
Engine speed: 3.000 rpm0.3- 3v
Evaporative
emission purge
solenoid ignition switch: ON
Keep the engine speed at 3,000 rpm after the
warmed-up engine is started.B+
o-3v
12Ignition timing
adjustment terminal
ignition
Ground the ignition timing adjustment o- 1vswitch:
terminal.ONRelease the ground of the ignition4.0- 5.W timing
adjustment terminal.
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Specifications/Special Tools/FUEL SYSTEM
SERVICE SPECIFICATIONS
13-119 MlOCB-
Items
Specifications
Basic ignition timing
5”f 2”BTDC at curb idle
Curb idle speed rpm
700-C 100
Idle speed when air conditioning is onvm
850 at neutral position
650 at
D range
Basic idle speed rpm
700+50
Throttle position sensor adjusting voltagemV 400-I ,00
0
Throttle position sensor resistance
kQ 3.5-6.
5
Intake air temperature sensor resistance
kQ2.7 [at 20°C (68”F)]
Engine coolant temperature sensor resistancekQ
20°C (68°F)2.4
80°C (176°F) 0.3
Oxygen sensor output voltageV 0.6-1.0
Fuel pressurekPa (psi)
Vacuum hose disconnection
330-350 (47-50) at curb idle
Vacuum hose connection Approx. 270 (38) at curb idle
Injector coil resistance
5213-16 [at 20°C (68”F)]
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TORQUE SPECIFICATIONS
Refer to P.13-6.
SEALANT
Refer to
P.13-7.
SPECIAL TOOLS
Refer to
P.13-7.
MlBDA-B
TROUBLESHOOTING
EXPLANATION OF TROUBLESHOOTING
PROCEDURES
MllEBCC
Refer to P.13-8.
EXPLANATION AND PRECAUTION RELATED
TO HARNESS CHECKING
Refer to P.13-9.
FUEL SYSTEM
ON-BOARD DIAGNOSTIC
The engine control module monitors the input/out- put signals (some signals at all times and the others
under specified conditions) of the engine control
module.
When it is noticed that an irregularity has continued
for a specified time or longer from when the irregu- lar signal is initially monitored, passing a certain
number, the engine control module judges that an irregularity has occurred, memorizes the diagnostic
trouble code, and outputs the signal to the on-board
diagnostic output terminal.
There are 15 on-board diagnostic items including
the normal state, and the diagnostic results can be read out with a voltmeter or scan tool.
Moreover, since memorization of the diagnostic
trouble codes is backed up directly by the battery,
the diagnostic results are memorized even if the ig- nition key is turned off. The diagnostic trouble
codes will, however, be erased when the battery
terminal or the engine control module connector is
disconnected. In addition, beginning with the engine
control module of
1990 and later models, the diag-
nostic trouble codes are erased by turning on the
ignition switch and sending the diagnostic trouble
code erase signal from the scan tool to the engine
DIAGNOSTIC CHART (FAULT TREE) control module.
Caution
If the sensor connector is disconnected with
the ignition switch turned on, the diagnostic
trouble code is memorized. In this case, send
the diagnostic trouble code erase signal from
the scan tool to the engine control module or
disconnect the battery terminal
(-) for 10 sec-
onds or more, and the diagnostic memory will
be erased.
The 15 on-board diagnostic items are provided as
follows, and if plural items are activated, they are all indicated sequentially from the smallest code num-
ber.
Caution
The diagnostic trouble code of ignition timing
adjustment signal is outputted when terminal
for ignition timing adjustment is short-cir- cuited. Therefore, it is not abnormal that the
code is outputted even when terminal for igni-
tion timing adjustment is short-circuited at the
time of ignition timing adjustment.
r
No.Output signal pattern
:i1zA0104
11
12
I3
:-J-l-J-12Ao104
Diagnostic trouble code-I
-
On-boarddiagnosticitem
Engine
control moduleCheck item (Remedy)IMemory
(Replace engine control module)-
Oxygensensorl Harness and connectorRetainedl Oxygen sensorl Fuel pressurel Injectors (Replace if defective.)l Intake air leaks
Volume air
l Harness and connectorRetainedflow sensor(If harness and connector are
normal, replace volume air flow
sensor assembly.)
Intake airl Harness and connector Retained
temperaturel Intake air temperature sensorsensor
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13-126FUEL SYSTEM
FAILSAFE/BACK-UP FUNCTIONS LIST
If trouble with any major sensor is detected by the on-board diagnostic,\
the vehicle will be kept in the safe
driving conditions according to the preset control logic.
Trouble item Control content for trouble
Volume air flow(1)Fuel injection timing and ignition timing are determined according to th\
e throttle positionsensorsensor (TPS) and engine revolution speed signal (crankshaft position \
sensor signal).(2)The IAC motor is fixed in the appointed position so idle air control is not per\
formed.
Intake air temperature The control is executed with the suction air temperature regarded as
25°C (77°F).sensor
Throttle position The fuel injection rate is not increased for acceleration according to t\
he throttle position
sensor (TPS)sensor signal.
Engine coolantThe control is executed with the coolant temperature regarded as 80°C (176’F).temperature sensor
Camshaft positionSimultaneous injection of fuel is executed for all cylinders. (In this \
case, the
No.1 cylinder top
jenS0r
dead center is not detected at all after the ignition key is turned
on.)3arometric
pressure The control is executed with the pressure regarded as 760 mmHg
(30 in. Hg.).
sensor
AC valve position Idle air control motor is not performed.;ensor
Ixygen sensor
Closed loop control of the air/fuel mixture ratio is not executed.
READ OUT OF DIAGNOSTIC TROUBLE CODE
Refer to P.13-16.
EbW&R MEMORY OF DIAGNOSTIC TROUBLE
Refer to
P.13-17.
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FUEL SYSTEM
CHECK CHART CLASSIFIED BY PROBLEM SYMPTOMS
ProblemsymptomsStartingIdling stability Drivingr”
.-
%scn
E5
$4.a,o_
5;i
cz
iP.13-143
-
Ea,Ll2a
F.- s
G-
DE-
c-
Elc
-
-
>El
)El-
)I3-
)@I
I-
-
i
-
5‘32a,$%ba”
D&l DEI
i>El
-0%,a>+y -2.gPE.-50 z.E r2?p9 6=& g-
-
-Sheck items
‘ower
supply
%ginecontrol module power groundI
1 P.13-146
:uel pump
Jolume air flow sensor
B
f
E3
DELI @El
cP.13-162
P.13-165III P.13-167I
1/ P.l3-171 1
P.l3-172
P.l3-173
P.l3-175
P.13-176
P.l3-179
ntake air temperature sensor
BIB
DEI
0
DEl
3El
3
-I
iarometric
pressure sensor
ingine coolant temperature
sensor
‘hrottle position sensor
Iosed throttlepositionswitch
K valve oosition sensor
lamshaft position sensor
i-:rankshaft positionsensorIIlnition
switch-ST
-I---0lnition switch-ST and park/neutralosition switch
chicle
speed sensor
ower steering pressure switch
ir conditioning switch and/C compressor clutch relayI/I- IIlxygen sensor
@El@ P.l3-181
@ElP.13-184
@[email protected]
Ile air control motor (DC motor)
inition coil and ignition powerOFI@piJOEIansistor
tiaporative emission purge solenoid01 P.13-189
1 Id
kl
c
tr
t
EGR solenoid
Fuel pressureOIlI @El8E.l @El @El @[email protected]
0 : Warm engine (number inside indicates check order)
0 : Cold engine (number inside indicates check order)
PROBLEM SYMPTOMS TABLE (FOR YOUR INFOMATION)
Refer to P.13-19.
TSB Revision
13-134FUEL SYSTEM (SOHC-16 VALVE> -Service Adjustment Procedures
BASIC IDLE SPEED ADJUSTMENTMlIFHBX
NOTE
1. The standard idling speed has been adjusted, by the en-
gine speed adjusting screw, by the manufacturer, and
there should usually be no need for readjustment.
2. Use the following procedure to adjust when the idling speed drops due to an incorrect adjustment, high idling
speed, or when a load such as the air conditioning is ap-
plied on the engine.
3. The adjustment, if made, should be made after first con- firming that the spark plugs, the injectors, the idle air con-
trol motor, the compression pressure, etc. are all normal.
(I ) The vehicle should be prepared as follows before the inspec- tion and adjustment.
l Engine coolant temperature:
85-95°C (185-203°F)
l Lights, cooling fan and accessories: OFF
l Transaxle: neutral (A/T for
P range)
l Steering wheel: neutral position
(2) Connect the scan tool to the data link connector (white).
NOTE
When the scan tool is connected, the diagnostic test mode control terminal should be grounded.
(3) If the scan tool is not used, follow the steps below.
@I Insert a paper clip into the l-pin connector (blue) shown in the figure at the left.
0 Connect a primary-voltage-detection type of tacho-meter to the paper clip.
1 TSB RevisionI