MITSUBISHI GALANT 1989 Service Repair Manual

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
TSB Revision
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
TSB Revision 7FUO653
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
TSB Revision1
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.
TSB Revision

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
TSB Revision
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
TSB RevisionI
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.

13-166
On-Vehicle Inspection of MFI
FUEL SYSTEM
- Components
INSPECTION
Using Oscilloscope Refer

to P.13-69.
HARNESS INSPECTION
c
IIlFUO633j switch
1218 Harness -.-..-Aside
connectorCheck for continuity of the ground
circuit.
l Crankshaft
position sensor connec-
tor: Disconnected
Ground) lFUO634
I
3:
@ Harnessside connectorfF
68
Engine control
module harness
side connector
J 9P-
l Crankshaft position sensor connec-
tor: Disconnected
9FUOO29 II
Check for open circuit or short circuit
to ground, between camshaft position
sensor and engine control module.
l Engine control module connec- tor: Disconnected
Measure the impressed voltage.
l Crankshaft position sensor connec- tor: Disconnected
l Engine control module connec-
tor: Connected
l ignition switch: ON
Voltage
(V)
4.8 - 5.2 module
TSB Revision

FUEL SYSTEM VALVE> - ::ii,,:::ti=pection Of MF’13-167
CRANKSHAFT POSITION SENSOR
@ Equipment
side connector
Output characteristic (V)
::
L*Time
One rotation of distributor
01R0103
Engine control module connector
@ Harness sideconnector
Enginecontrol
module
Ignition switch (IG,)
IDistributor
Crankshaft position
sensorI/\2
B
/\
TSB RevisionI
Oscillo
1 I”69 ,.68
I
IL hh5V5v 7FUO653
9FUOO27

13-168FUEL SYSTEM - ::ii$%%spection Of MF’
OPERATION
l The crankshaft position sensor detects thecrank angle (piston position) of each cylinder,
converts it to a pulse signal and inputs it to the
engine control module. The engine control mod- ule computes the engine speed and the intake
air amount for one stroke and outputs the injec-
tor drive signal and injection command signal
based on this signal.
0Power to the crankshaft 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 crankshaft position sensor output
terminal, and the crankshaft position sensor generates 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 unexpected shocks are felt during driving or the engine stalls suddenly during idling,
shake the crankshaft position sensor har- ness. if this causes the engine to stall, poor
contact of the sensor connector is sus-
pected.
Hint 2: If the crankshaft position sensor outputs a
pulse signal when the ignition switch is
turned to ON, (without starting the engine),
the crankshaft position sensor or engine control module is probably defective.
Hint 3: If the tachometer reads 0 rpm when the en- gine that has failed to start is cranked, faulty
crankshaft position sensor or broken timing
belt is suspected.
Hint 4: If the tachometer reads 0 rpm when the en- gine that has failed to start is cranked, theprimary current of the ignition coil is not
turned on and off. Therefore, troubles in the ignition circuit and ignition coil or faulty igni-
tion power transistor is suspected.
Hint 5: If the engine can be run at idle even though
the crankshaft position sensor reading is out
of specification, troubles are often in other
than the crankshaft position sensor. [Examples]
(1) Faulty water temperature sensor
(2) Faulty idle air control motor
(3) Poorly adjusted basic idle speed
TSB Revision