1989 MITSUBISHI GALANT Service Repair Manual

FUEL SYSTEM -On-Vehicle Inspection of MFI Components
CRANKSHAFT POSITION SENSOR
[VI 1 Output characteristic
One rotation of crankshaft position sensor
01R0’03
Engine controlmqdule21
R5VJ7FUO499I

Multiport fuel
injection relay
@ Component sid
e
connector
MlBYhlABl
OPERATION
TROUBLESHOOTING HINTS
INSPECTION-Using Scan tool
INSPECTION-Using Oscilloscope
Refer to
P.13-281.
HARNESS INSPECTION
11 I
1’1
Measure the power supply voltage.
@Harness
side. Connector: Disconnected
connector Ignition switch: O
N
Voltage (VI
Battery positive voltage
-
7FUO496
Repair theharness.-+ (@a-Multi-port fuel in-jection relay)
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13-284FUEL SYSTEM - On-Vehicle Inspection of MFI Components
(
Check for continuity of the groundcircuit.
. Connector: Disconnected
7FUO497
Repair theharness.
* cm-Ground)
a Harness side connectorCheck the voltage of the output
cir- cut.
. Connector: Disconnected
. Ignition switch: ON
7FUOSOlL
IGNITION SWITCH-ST
Refer to P.13-77.
M13VNAAa
IGNITION SWITCH-ST AND PARK/NEUTRAL
POSITION SWITCHM13YOAc
Refer to P.13-78.
VEHICLE SPEED SENSOR
Refer to P.13-80.
M13YPAAa
POWER STEERING PRESSURE SWITCHM13VQAAa
Refer to P.13-81.
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FUEL SYSTEM -On-Vehicle Inspection of MFI Components13-285
AIR CONDITIONING SWITCH AND A/C COMPRESSOR CLUTCH RELAYmt3n7.4al
Jk: L 1 /J l-k~-~+ L!- Air conditioning switch
0
/’
’ ’ -~.i>
‘\ /,
(\ QeF --:
’ -q,,T
(‘a/ A-.,>*/ \
) !I/ ,+f---J;I’,,p
s- / :\,$jy W/’
\mc-- -; --
\\ \\$ &
IF -~1. bI /~-~ i E--z
\ \I i
!
L-,-1&L.- ~~~~.
6FUO845 I
Sub fusible link
‘7 IpI Z%37°GZressor
2 Dual pressure
switch
1
t
Air conditioning OFF
engif’Ie codant* temperatureON switc
h
T
2
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Engine control module
,(65 1\7
v v
Engine control module connector6FU1457
OlLo838
OPERATION
l
The air conditioning switch applies battery vol-
tage to the engine control module when the
air
conditioning is switched ON.
TROUBLESHOOTING HINTS
If the air conditioning compressor’s magnetic clutch
is not activated when the air conditioning switch
is switched ON during idling, it is probable that the
.When the air conditioning signals are input, the
engine control module activates the idle air con-
trol motor, and also switches ON the power
transistor. As a result, current flows to the A/C
compressor clutch relay coil and the relay
switch is switched ON, the air conditioning
compressor’s magnetic clutch is activated.
cause is a malfunction of the air conditioning control
system.

13-286FUEL SYSTEM - On-Vehicle Inspection of MFI Components
INSPECTION Using Scan tool
Air conditioning switch
Function Item No.
Data reading 28
Data displayCheck conditionsAir conditioning switchNormal
display
Switch status
. Engine idlingOFF OFF
(The air conditioning
compressor should beONONactivated when the air
conditioning switch is
switched ON.)
Air conditioning compressor clutch relay
Function
Item No.
Data reading 49
Data display
Check conditionsAir conditioning switchNormal display
Air condition-
. Engine: idling afterOFFOFF (Compressor
ing compres-warm up clutch non-
sor clutch
activation)
relay status ON
ONKompressorclutch activation)
HARNESS INSPECTION________ --- -__-. -- ~~-
Measure the power supply voltage of
the air conditioning circuit.
. Engine control module connec-tor: Disconnected- Ignition switch: ON+ Air conditioning switch: ON
side connector
AIR CONDITIONING INSPECTION
Refer to GROUP 55-Air Conditioning.
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FUEL SYSTEM -On-Vehicle Inspection of MFI Components 13-287
KNOCK SENSOR
M13zAAA
Engine control module
1 @ Component side
Oscillo
connector
I it’
ti hoc: !A!’ A2 II Isensor ! T1II
ISEL12081
@ Harness side
connector
OPERATION
The knock sensor converts cylinder block vibrations
due to knocking into voltage according to the
strength of the vibrations and inputs it to the engine
TROUBLESHOOTING HINTS When knocking occurs when driving at maximum load, the following troubles, other than the knock
control module.
The engine control module controls the delay in
spark timing according to this signal.
sensor, can be inferred. (1) Incorrect spark plug heat rating
(2) Incorrect gasoline
(3) Mis-adjustment of standard spark timing
Normal waveform 03A0205INSPECTION
Using Oscilloscope
(1) Connect the probe to the oscilloscope pick-up point as shown in the circuit diagram.
(2) Rev up the engine to 5,000 rpm, and check the waveform.
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12,7QQFI IFI GVSXFM - On-Vehicle lnmection
of MFI ComponentsId-LuvI “Lh V.V. h.1. .--..v-_.. .- .
connector Measure the terminal voltage.
. Connector: Disconnected
pf?q f$!?;
1 FU0513
Check for continuity of the ground
circuit.
. Connector: Disconnected
@p/LA
Repair the
harness.
KBB-Ground)
76FU1302
EGR TEMPERATURE SENSOR hn3m1
fiFU1424
Component side EGR temperature sensor
connectorI
1
. /
r
t-lA 17 A24 J
I
;
t
\15
Engine
control module
lrn5v
6FU1269
Harness side @
connector
!?ll
@lfiii
t?rl2 1 KL1202
ITemperature1521005
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FUEL SYSTEM -On-Vehicle Inspection of MFI Components13-289
OPERATION
l The EGR temperature sensor functions to con-
vert the data regarding the temperature of the
EGR gas downstream from the EGR valve to
voltage, and to input that voltage (as signals) to
the engine control module.
lThe 5V power supply within the engine control
module is supplied, by way of the resistance
within the unit, to the EGR temperature sensor;
it passes through the EGR temperature sensor,
which is a type of resistor, and is grounded at the engine control module.
Note that the resistance of the EGR tempera-
ture sensor decreases when the EGR gas vol-
ume increases and the temperature of the EGR
gas increases.
l The EGR temperature sensor terminal voltage
becomes higher when the resistance of the EGR
temperature sensor increases, and becomes lower when the resistance decreases.
Consequently, the EGR temperature sensor
terminal voltage varies in accordance with the
temperature of the EGR gas, becoming lower when the temperature of the EGR gas
in-
creases.
INSPECTION Using Scan tool
Function Item No.
Data reading
43
Data display 1 Inspection conditions1 Engine condition1 Standard valueI
Sensor. Engine: warm upIdling100°C (212°F) or lower
temoerature* Enaine is maintained in Ia &nstant state for 2
minutes or more
. Remove the vacuum
11 7J$lfifiF~ nr lower 1
hose (green stripes) fromthe EGR solenoid and3,500 rpm150°C (302°F) or higher/hlnn-Turbo>plug both the removed
vacuum hose end and
solenoid valve nipple.
HARNESS INSPECTION
Harness side
connector Measure the power supply voltage.
. Connector: Disconnected
. Ignition switch: ON
Voltage
(V)Repair the
Harness side
connector Check for continuity of the ground
circuit.
. Connector: Disconnected
SENSOR INSPECTION Refer to GROUP
l7-Exhaust Gas Recirculation (EGR) System.
Repair theharness.
@El-IIll. q l)
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13-290FUEL SYSTEM - On-Vehicle Inspection of MFI Components
HEATED OXYGEN SENSOR
M13YSAAa
sensor connector
2Theoretical A/F
8.5
P.-
5
E
Pt;2Lw1415 16
AJFEC1007
Component side
Heated oxygen
. sensor
y3y4 $1y2
nri rlT” IIMultiport fuel
injection relayd; II
TII :‘aII Il. 7
Engine control module x4H106@ Harness side
connector
OlLoB38
OPERATION
l The heated oxygen sensor functions to detect
the concentration of oxygen in the exhaust gas;
it converts those data to voltage, and inputs the
resulting signals to the engine control module.
l If the air/fuel mixture ratio is richer than the
theoretical air/fuel mixture ratio (i.e., if the con-
centration of oxygen in the exhaust gas is
sparse), a voltage of approximately IV is output;
if the air/fuel mixture ratio in leaner than the
theoretical air/fuel mixture ratio (i.e., if the con-centration is dense), a voltage of approximately
ov is output.
TROUBLESHOOTING HINTS
HINT 1:
The exhaust gas purification performance will wor-
sen if there is a malfunction of the heated oxygen
sensor.
Hint 2:
If the heated oxygen sensor output voltage deviates
from the standard value even though the results of
the checking of the heated oxygen sensor are nor-
mal, the cause is probably a malfunction of a com-
ponent related to mixture control.
l The engine control module, based upon those
signals, regulates the amount of fuel injection so
that the air/fuel mixture ratio becomes the
theoretical air/fuel mixture ratio.
lBattery power supply is applied, by way of the
multiport fuel injection relay, to the oxygen sen-
sor heater. As a result, the sensor element is
heated by the heater, so that the heated oxygen
sensor shows excellent response even if the
temperature of the exhaust gas is low.
Examples:
(1) Malfunction of an injector.
(2) Air leakage into the intake manifold from a leak-
ing gasket.
(3) Malfunction of the volume air flow sensor, the intake air temperature sensor, the
barometric-
pressure sensor, or the engine coolant tempera-
ture sensor.
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