engine MITSUBISHI GALANT 1989 Service Repair Manual

13-156On-Vehicle Inspection of MFI
FUEL SYSTEM (SOHC-16 VALVE> - Components
OPERATION
TROUBLESHOOTING HINTS INSPECTION
Using Scan Tool
Refer to
P.13-55.
HARNESS INSPECTION
Harness side
connector
Check for continuity of the ground
circuit.
l Engine coolant temperature sensor connector: Drsconnected
9FUO112
01
OK+ /2/
Repair the
& harness.
i @lz -@i,
r
21t@ Harness sideconnector
2 1
7
Check for open circuit or short-circuit
to ground, between engine coolant
temperature and engine control mod-
!:I->,
OK+ 131
ule.
l Engine coolant temperature
connector: Disconnected
l Engine control module connec-
~ 1 h h L
~
tor: Disconnected$)#!& ” g$jnii
7 7
c
module harness
side connector
9FUO113
3
@ Harness side connectx
Measure the Impressed
voltage.
l Engine coolant temperature sensor
connector: Dlsconnected
l Engine control module connec- tor: Connected
l Ignition switch. ON Replace
& the engine
control ,
I
9FUO114
moaure.
SENSOR INSPECTION
Caution
J
Be careful not to touch the tool against the connector (resin
section) when removing and installing.
(1) Remove engine coolant temperature sensor from the ther- mostat housing.
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FUEL SYSTEM (SOHC-16 VALVE> - ::ii,,k%ti=pec*ion Of MF’13-157
9FUO156
9FUO157
THROTTLE POSITION SENSOR
MinimumMaxlmum
Throttle shaft turning angle162461
(21 With temperature sensing portion of engine coolant tem-
perature sensor immersed in hot water, check resistance
Temperature PC (“F)lResistance (k!S)
0 (32)5.8
I20 (68)~12.4I
I80 (I 76)I0.3I
Engine control module connector
(3) If the resistance deviates from the standard value greatly,
replace the sensor.
INSTALLATION
(1) Apply sealant to threaded portion. Specified sealant:
3M NUT locking Part No. 4171 or
equivalent
(2) Install engine coolant temperature sensor and tighten it to specified torque.
Sensor tightening torque:
20-40 Nm (15-29 ft.lbs.)
(3) Fasten harness connectors securely.
@ Equipment sideconnectorThrottle posltlon sensor
@ Harness srdeconnector
pJ$q]
1
5EL1400
I72-
E
6461
r 1
Engine control module
7FUO672
L
7FUO653
1 TSB Revision

On-Vehicle Inspection of MFI
13-158FUEL SYSTEM (SOHC-16 VALVE> - Components
OPERATION
aThe throttle position sensor converts the throttle position opening into a voltage and inputs it to the
engine control module, which
then controls
the
fuel injection, based on the input signal.
l The
5V power in the engine control module is
supplied to the throttle position sensor. It flows
through the resistor in the sensor and is then
grounded in the engine control module.
lAs the throttle valve shaft rotates from the idle position to wide open position, the resistancebetween the variable resistor terminal of the
throttle position sensor and the ground terminal increases. As a result, the voltage at the throttle
position sensor variable resistance terminal also
increases.
INSPECTION
Using Scan Tool TROUBLESHOOTING HINTS
Hint 1: The throttle position sensor signal is more important in the control of automatic trans-
axle than in the engine control. Shifting
shock and other troubles will be caused if
this sensor is faulty.
Hint 2: If the output voltage of the throttle position
sensor is out of specification, adjust the
sensor and check the voltage again.
If there is an evidence of disturbed fixed SAS
setting, adjust the fixed SAS.
Function item No.Data displayCheck conditionThrottle valve Standard value
Data14Sensor Ignition
switch: ON At idle position 300 - 1000 mV
readingvoltage
Open slowlyIncreases with valve
opening
Open widely 4,500
- 5,500 mV
HARNESS INSPECTION
-
i1
@ Harness sideconnector
Check for continuity of the ground
circuit.
l Throttle position sensor connector: Disconnected
Repair the
harness.
(ml-m
3 Harnessside connetor
P
ECMharness sidef connector
Check for an open-circuit, or a short-
circuit to ground between the engine
control module and the throttle posi-
tion sensor.
l Throttle position sensor connector:
Disconnected
l Engine control module connec-
tor: Disconnected Repair the
harness. @El

- El)
(@III-ElII
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FUEL SYSTEM - ~:~t%~t~pection Of MF’13-159
@ Harness sideconnector
Measure the impressed voltage of the
throttle position sensor.
l Throttle position sensor connector:
Disconnected
l Engine control module connec-
tor: Connected
76FU1241
7FlJO485
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7FUa673
SENSOR INSPECTION
(1) Disconnect the throttle position sensor connector.
(2)Measure the resistance between the throttle position sensor
side connector terminal @ and terminal @.
Standard value: 3.5
- 6.5 kQ
(3)Measure the resistance between the throttle position sensor side connector terminal
@ and terminal @.
Throttle valve slowly opensChanges smoothly in propor-
until fully open from the idletion to the opening angle of the
positionthrottle valve
(4)If the resistance is outside the standard value, or if it doesn’t
change smoothly,
replace the throttle position sensor.
NOTE
For the throttle position sensor adjustment procedure, refer
to
P.13-136.

On-Vehicle Inspection of MFI13-160FUEL SYSTEM (SOHC-16 VALVE> - Components
CLOSED THROTTLE POSITION SWITCH
za,
L
% ;; ----,-p
&
Throttle shaft turning angle 0,z092
@ Harness sideconnector
Engine control module
5v
‘il
67 72
II’1
1 -00, Closed
1/ 1
throttleposition
@ Equipment srdeswitch34
connector
ITT-l
7‘F:UO674
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OPERATION
l The closed throttle position switch senses whether the accelerator pedal is depressed or
not, converts it into high/low voltage and inputs
the voltage to the engine control module, which
then controls the idle air control motor based on
the input signal.
l A voltage is applied to the closed throttle posi-
tion switch from the engine control module.
When the accelerator pedal is released, the closed throttle position switch is turned on to
conduct the voltage to ground. This causes the closed throttle position switch terminal voltage
to go low from high.
INSPECTION
Using Scan Tool
Refer to
P.13-62.
TROUBLESHOOTING HINTS If the closed throttle position switch harness and in-
dividual check results are normal but the closed
throttle position switch output is abnormal, the fol-
lowing troubles are suspected.
(1) Poorly adjusted accelerator cable
(2) Poorly adjusted fixed SAS

FUEL SYSTEM - :::;k%l;nspection Of MF’13-161
HARNESS INSPECTION
Check for open-circuit, or short-circuit
to ground, between closed throttle position switch and engine control
module.
l Engine control module connec- tor: Disconnected
l Closed throttle position switch
connector: Disconnected
@ Harness side^^^^^^ *^-
Check for continuitv of the groundt.
l Llosed
throttle position switch
connector: Disconnected
1
! Repair
the
4 harness.
6FU1242 /
connector
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Measure the impressed voltage of
the closed throttle position switch.
l Connector: Disconnected
l Engine control module connec-
tor: Connected
l Ignition switch: ON
Voltage
(VI
I
I Replace
I the engine
7 control
14 or more1 module.
7FUO676
SENSOR INSPECTION
(I) Disconnect the throttle position sensor connector.
(2) Check the continuity between the throttle position sensor connector side terminal
@I and terminal @.
(3) If out of specification, replace the throttle position sensor.
NOTE
After replacement, the throttle position sensor and closed
throttle position switch should be adjusted. (Refer to
P.13-
136.)

On-Vehicle Inspection of MFI13-162FUEL SYSTEM (SOHC-16 VALVE> - Components
IAC VALVE POSITION SENSOR
@
Equipment side
connector 7FlJO653
Enginecontrol
module
IAC valve position sensor
h61 A\5
A72 Al8
% 5v
I
9FUOO26
OPERATION
l The
IAC valve position sensor converts the
changes (increase or decrease) in the valve
position of the idle air control motor into pulse
signals and inputs these signals to the engine
control module. The engine control module de-
termines the valve position from these signals and also controls the idle air control motor.
l
5V power is supplied to the IAC valve position
sensor from the engine control module, and the
ground connection is positioned in the engine
control module.
l
5V power is applied to the two IAC valve posi-
tion sensor output terminals from the engine control module. When the
IAC valve position is
changed (increased or decreased) by the DC motor inside the idle air control motor, the
IAC
valve position sensor generates a pulse signal
from the opening and closing between the out-
put terminal and the ground. TROUBLESHOOTING HINTS
Hint 1: The
IAC valve position sensor is the most
important sensor for controlling the idle
speed. If a malfunction develops when the
engine is idling and the engine load is varied
by turning the air conditioning switch to ON
and OFF, etc., this sensor is probably defec-
tive.
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FUEL SYSTEM - :::,:k:t?=tiion Of MF’13-163
INSPECTION
Using Scan Tool
Function
( Item No.
Data reading
/ 5
5
l-
+
L
Data display
IAC valve
position step
TCheck condition
l Engine coolant tem- perature: 85 to
95°C
(185 to 203’F)l Lights, electric cool- ing fan, accesso-
ries: OFF
l Transaxle: Neutral
(P range for A/T)
l Closed throttle posi-
tion switch: ON
l Engine: At idle
(Compressor clutch
to be operating in case air conditioning
switch is ON) Load state
Air conditioning switch:
OFF
Air conditioning switch:
Turn from OFF to ON l Air conditioning switch: OFF
l Selector lever: Shift to
D range
,,,,,,,,,I
Increase from 3-40 I
step
NfOTE
In a new vehicle [driven approximately 500 km (300 miles) or less], th\
e IAC valve position sometimes exceeds the
standard value by approximately 20 steps.
Caution
When shifting the selector lever to the
D range, apply brake to prevent the vehicle from moving forward.
HARNESS INSPECTION
IIL\-11 r@Harm ” ’ -conna
tA Engine control
-tmodule harnessside rnnnnctor
Check for open circuit, or short-circuit
to ground, between engine control module and
IAC valve position sensor.
l Engine control module connec- tor: Disconnected
l
IAC valve position sensor connec-
tor. Disconnected
21
@Harness sideconnector
0,OK-& 121
i Repair the
--L
harness
(@lcl- El)
/ ml-~) (@pJ
- @I)
Check for continuity of the ground
circuit.
l
IAC valve position sensor connec-
tor: Disconnected

13-164
On-Vehicle Inspection of MFI
FUEL SYSTEM
(SOHC-16 VALVE> - Components
Measure the impressed voltage.
lIAC valve position sensor connec-
tor: Disconnected
l Engine control module connec-
tor: Connected
*6FU1724
$Harness side
connector
Measure the impressed voltage.
l
IAC valve position sensor connec-
tor: Disconnected
*
Engine control module connec-
tor: Connected
l Ignition switch: ON 6FU1723
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1

FUEL SYSTEM (SOHC-16 VALVE> - %$k%lnspectio” Of MF’13-165
CAMSHAFT POSITION SENSOR
@ Equipment side
connector
Output
characteristic PJ)
‘One rotation of distributor
@ Harness stdeconnector
lgnltion switch (IG,)
Distributor pistributor& 2 ,
I
z
Camshaft
position
Engine
control
module
Engine control module connector
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7FUO6539FuOO27
OPERATION
l The camshaft position sensor detects the top dead
center

on the
compression
stroke
of
the
No.1 cylinder, converts it into a pulse signal and
inputs it to the engine control module. The en-
gine control module determines the fuel injec-
tion sequence based on this signal.
l Power to the camshaft position sensor is sup-
plied from the ignition switch (IG), and the
ground is located in the engine control module.
A
5V voltage is applied from the engine control
module to the camshaft position sensor output
terminal, and the camshaft position sensor gen-
erates a pulse signal as it switches from OPEN
to SHORT (power transistor inside the sensor
switches ON/OFF) between the output terminal
and the ground. TROUBLESHOOTING HINTS
Hint 1: If the camshaft position sensor is defective, proper sequential injection will not occur, so
the engine will stall, or unstable idling and poor acceleration will occur.
Hint 2: When the camshaft position sensor outputs a pulse signal when the ignition switch is
turned to ON (without starting the engine),
the camshaft position sensor or engine con-
trol module is probably defective.