1989 MITSUBISHI GALANT Service Repair Manual

FUEL SYSTEM - On-Vehicule Inspection of MFI Components13-43
HARNESS INSPECTION
Harness sideconnector
Measure the power supply voltage of
the multiport fuel injection relay.
.
Multiport fuel injection relay con-
nector: Disconnected
. Ignition switch: ON
q2
Check for continuity of the groundIcircuit.
* Multiport fuel injection relay con-
nector: Disconnected
Repair the
harness.
VBEil-Ground)
J
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@Harness side
connector Repair the
harness.
l
(Ignition
switch-
@5)
OlA0361
Measure the power supply voltage of
the multiport fuel injection relay.
* Multiport fuel injection relay con-
nector: Disconnected
El4
Repair the
harness
FE&
-
@Harness
side connector Check for open-circuit or short-circuit
to ground between the engine con-
trol module and the
multiport fuel in-
jection relay.
. Engine control module connec-
tor: Disconnected
.
Multiport fuel injection relay con-
nectar:
Disconnected Repair the
harness
llEW&Bl)
llIEl-@5)

‘13-44 FUEL SYSTEM - On-Vehicule Inspection of MFI Components6FUO751
EC1163
When applying battery voltage directly, make sure that it
is applied to correct terminal. Otherwise, the relay could
be damaged.
(1) Check continuity of the multiport fuel injection relay coil.
IMeasuring terminals Continuity
MULTIPORT FUEL INJECTION RELAY INSPECTION
Caution
111 Conductive (approx. 9551)
Conductive (approx. 35 52)
@-@IConductive in one
direction only
(2) Check the continuity of the multiport fuel injection relay contacts between terminals
@-@.
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Relay coil
(between terminals @>-a)Continuity
I
Gienergized1 Non-conductive (=S2)
Energized Conductive (OQ)
(3) Check the continuity of the multiport fuel injection relay
contacts between terminals
0-O.
(4) If not as specified, replace the multiport fuel injection relay.

FUEL .SYSTEM -On-Vehicule
Inspection of MFI Components13-45
ENGINE CONTROL MODULE POWER GROUND MlJYDAA
control module Engine control module
p7 v
101
F
106
Engine control module connector
01A0191
OlL0838
1
OPERATION
Grounding of the engine control module.
TROUBLESHOOTING HINTS
If there is incorrect or incomplete contact of the en-
aine control module’s ground line, the engine con-
?rol module will not function correctly.
HARNESS INSPECTION
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IJ
Engine control module
harness side connector Check for continuity of the ground
circuit wiring.
* Engine control module connector: Disconnected
harness
--* !!%nd
Rind)

13-46 FUEL SYSTEM VALVE>- On-Vehicule Inspection of MFI Components
FUEL PUMP
MlBYEAB
@ Component side connector
-
\
1Fuel pump M
$
1
I

-
Multiportfuel
injection
relay
Component side
7/-/
L2 :<
\
6’
_!
4,
@connector,
I-~ i1SlLl”’-------.,\OFF I OIL
,’e-
\/ \/1\/ \/5 1 2
’
-
I
IT-----

-
1!
check terminal -5EL1200j
Engine
control module @ Harness side
connector
@ Harness side
connector
I
6FU1236
Engine control module connector OlLO838
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FUEL SYSTEM - On-Vehicule Inspection of MFI Components 13-47
OPERATION
l
Activates the fuel pump during engine cranking
and while the engine is running.
l When the ignition switch is set to the START
position, current flows, by way of the
multiport
fuel injection relay coil, from the ignition switch
to ground. As a result, the
multiport fuel injec-
tion relay switch is switched ON, and the power
for activation of the fuel pump is supplied, by
way of the
multiport fuel injection relay switch,
from the battery to the fuel pump.
INSPECTION
Using Scan tool
l While the engine is running, the engine control
module switches ON the power transistor, after
which current flows to the
multiport fuel injec-
tion relay coil, and the power for activation of
the fuel pump is supplied to the fuel pump.
l When the
multiport fuel injection relay switch is
switched ON, battery voltage is also applied to
the engine control module, and so the engine
control module detects the fact that the power
for activation of the fuel pump is being supplied
to the fuel pump.
Function Item
No.
Actuation Inspection conditions DescriptionNormal condition
Actuator test 07 Actuates fuel
. Engine cranking Hold the return hosePulsation can be felt.
pump, clrcu-
. Fuel pump forced between two fingers
lating fuel. activation
so as to feel the
The inspection pulsation of the
flow-should be conducteding of fuel.
for both of the above conditions. Listen to the pump
Pump sound can besound at a place nearheard.the fuel tank.
Check for continuity of the ground
circuit.
I
. ;E;;,, pumpconnector: Discon-
2
1
Y-
!
Repair theharness.
@El- @ HarnessGround)connector
O~AOZOl3
I
Check for continuity between the fuel
pump and the checking terminal.
connector: Discon-
1
@uide 1
B
0. ;;;;,,
pump
L
Check the fuel pump.
. Apply battery voltage to the check-
ing terminal and operate the pump.
!I:7
OK
connector :1 = 6FUl238
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13-48 FUEL SYSTEM - On-Vehicule Inspection of MFI Components
Check for continuity between the
checking terminal and the engine
control module, and between the
multiport fuel Injection relay termi-nals.
connector
01 A0579
.
Multiport fuel injection relay con-
nector: Disconnected
. Engine control module connec-
tor: Disconnected
. Fuel pump connector: Discon-
netted
Repair the
harness.
Measure the power supply voltage of
the
multiport fuel injection relay.
.
Multiport fuel injection relay con-
Harness sideconnector
Engine control
module harnessCheck for an open-circuit, or a short-
side connectorcircuit to ground, between the multi-port fuel injection relay and the en-
gine control module.
. Multiport fuel injection relay con-
nectar:
Disconnected
. Engine control module connec-
tor: Disconnected Repair
the-+ harness.
(@a-8)
Harness side
connector
@
Check for continuity, of the ground
circuit.
- Multiport fuel injection relay con-
nectar:
Disconnected.
Repair
theharness.
a vmil-Ground)
@ Harness sideconnector
Check for an open-circuit, or a short-circuit to ground, between the multi-port fuel injection relay and the fuel
w-we Multiport fuel injection relay con-
nector: Disconnected
. Fuel pump connector: Discon-
nettedRepair the-+ harness.
GilIl-@El)T
OlA0401
MULTIPORT FUEL INJECTION RELAY INSPECTION
Refer to P.13-44.
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FUEL SYSTEM -On-Vehicule Inspection of MFI Components13-49
VOLUME AIR FLOW SENSOR
@ ;;vonent
connector
Intake air amount
(Wsec)162451
Multipoh fuel
injection relay
Volume air flow sensor
/\2/\N
Harness side
connector
IHjhcillo)
1.10
f-i5V
Engine
control
module
MlOYFAA
J 6FU1394
OPERATION
l The volume air flow sensor is incorporated
within the air cleaner; it functions to convert the
amount of engine air intake to pulse signals of a
frequency proportional to the amount of engine air intake, and to input those/signals to the en-
gine control module. The engine control module
then, based upon those signals, calculates the amount to fuel injection, etc.
TROUBLESHOOTING HINTS
Hint 1:
If the engine sometimes stalls, try starting the en-
gine and shaking the volume air flow sensor har-
ness.
If the engine then stalls, incorrect or improper con-
tact of the volume air flow sensor connector is the probable cause.
Hint 2:
If, when the ignition switch is switched ON (but the
engine is not started), the volume air flow sensor
output frequency is any value other than zero, a
malfunction of the volume air flow sensor or of the
engine control module is the probable cause. Hint 3:
If idling is possible even though the volume air flow
sensor output frequency is deviated from the stand-
ard value, the cause is usually a malfunction other
than of the volume air flow sensor. l The power for the volume air flow sensor is
supplied from the multiport fuel injection relay
to the volume air flow sensor, and is grounded at the engine control module. The volume air
flow sensor, by intermitting the flow of the
5V
voltage applied from the engine control module,
produces pulse signals.
Examples:
(1) The flow of air within the volume air flow sensor is disturbed. (Air duct disconnection or clogged
air cleaner element)
(2) Incomplete combustion within a cylinder. (Malfunction of spark plugs, ignition coil, injec-
tors, compression pressure, etc.)
(3) Air is taken into the intake manifold through a leaking gasket, etc.
(4) Incomplete close contact of the EGR valve seat.
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13-50 FUEL SYSTEM - On-Vehicule Inspection of MFI Components
INSPECTION
Using Scan Tool
Item No. Data display Inspection conditions
12Sensor de-
tection air
volume (fre-
quency) . Engine coolant
temperature: 85-95°C(185-205°F). Lights, cooling fan, elec-
trical accessories: OFF
. Transaxle: neutral (iVT
models: “P” range)
RacingFrequency in-
creases as racing
rpm increases.
NOTEThe volume air flow sensor output frequency may be about 10% higher than\
indicated above when the vehicle is new [driven approximately 500 km (300 miles) or less].
Regular waveform 03A0203
HARNESS INSPECTION
@
Harness sideconnector
6
0-0
~
0
=
Using Oscilloscope
(1) Run the engine at idle speed.
(2) Connect the probe to the
osilloscope pick-up point a
s
shown in the circuit diagram, and check the wave form.
Measure the power supply voltage.
. Connector: Disconnected
. Ignition switch: ON
--P
IRepair the
Harness sideconnector
Measure the terminal voltage.
. Connector: Disconnected
. Ignition switch: ON ~

0
OK’ 30
Repair the
harness
.
cm-an)
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