1998 MITSUBISHI LANCER EVOLUTION IV sensor

MPI – General Information13-2
MULTIPOINT INJECTION (MPI)
GENERAL INFORMATION
OMPI System Diagram

1 Injector

2 ISC servo

3 Fuel pressure control valve

4 Waste gate solenoid valve

5 Secondary air control solenoid valve
Control relay
Fuel pump relay
A/C relay
Ignition coil
Exhaust temperature warning lamp
Engine warning lamp
Diagnosis output
Alternator G terminal
Fan motor relay
Tachometer
Fuel pump relay No.2 1 Oxygen sensor
2 Air flow sensor
3 Intake air temperature sensor
4 Throttle position sensor
5 Idle switch
6 Camshaft position sensor
7 Crank angle sensor
8 Barometric pressure sensor
9 High temperature sensor
10 Engine coolant temperature sensor
11 Detonation sensor
Power supply voltage
Ignition switch-IG
Ignition switch-ST
Vehicle speed sensor
A/C switch
Power steering fluid pressure switch
Alternator FR signalEngine ECU
1 Oxygen sensor
2 Air flow sensor3
Intake air tem-
perature sensor
4,
5
6 Camshaft position
sensor
7 Crank angle sensor 8 Barometric
pressure sensor
9 High temperature
sensor 10 Coolant temperature sensor
11 Detonation sensor
1 Injector
2 ISC servo

3 Fuel pressure
control valve

4 Waste gate
solenoid valve
5 Secondary air
control solenoid
valveCanister
Check valveFrom
fuel
tank
Throttle position
sensor (with a
built-in
idle
switch)
Secondary
air valve
AirTo fuel
tankFuel
pressure
regulatorFrom
fuel
pump
Waste gate
actuator
Catalytic converter
Given above is the MPI system diagram for EVOLUTION-IV. The MPI system for EVOLUTION-V is different
from this in the following point;
Oxygen sensor with a heater is adopted.
The diagnosis connector power supply circuit is different.
The high temperature sensor is no longer used.

MPI – Service Specifications / Sealant13-3
SERVICE SPECIFICATIONS
ItemsSpecifications
Basic ignition timing BTDC5 ± 3
Basic idle speed rpm850 ± 50
Throttle position sensor adjusting voltage mV400 – 1,000
Throttle position sensor resistance kΩ3.5 – 6.5
ISC servo coil resistance (at 20C) Ω28 – 33
Intake air temperature sensor resistance kΩAt 20C2.3 – 3.0
At 80C0.30 – 0.42
Coolant temperature sensor resistance kΩAt 20C2.1 – 2.7
At 80C0.26 – 0.36
Fuel pressure
kPa {kgf/cm2}
When vacuum hose is connected230 {2.35}
kPa {kgf/cm2}
When vacuum hose is disconnected289 – 309 {2.95 – 3.15}
Injector coil resistance Ω2 – 3
Amount of injector fuel leak drop/min1 or less
Oxygen sensor output voltage0.6 – 1.0
Fuel pressure control valve coil resistance (at 20C) Ω28 – 36
SEALANT
ItemSpecified sealant
Coolant temperature sensorDrying sealant: HELMESEAL H-1M [0110513]
NOTE:
Given in [ ] are MITSUBISHI GENUINE PART numbers.

MPI – Special Tools13-4
SPECIAL TOOLS
ToolNumberNameUse
MB991348Test harness setMeasurement of voltage during trouble-
shooting
Inspection using an oscilloscope
MB991519Alternator harness
connectorMeasurement of voltage during
troubleshooting
MB991536TPS check
harnessAdjustment of idle switch and throttle position
sensor (TPS)
MD998464Test harness
(4-pin, square)Inspection of oxygen sensor
MD998463Test harness
(6-pin, square)Inspection of idle speed control servo
Inspection using an oscilloscope
MD998478Test harness
(3-pin, triangle)Measurement of voltage during trouble-
shooting
Inspection using an oscilloscope
MD998706Injector test setChecking the spray condition of injectors
MD998741Injector test
adaptor
MB991607Injector test
harness

MPI – Troubleshooting13-6
TROUBLESHOOTING
1. DIAGNOSIS FUNCTION
1-1 ENGINE WARNING LAMP (CHECK ENGINE LAMP)
If an abnormality occurs in any of the following items related
to the Multipoint Fuel Injection (MPI) system, the engine
warning lamp will illuminate.
If the lamp remains illuminated or if the lamp illuminates while
the engine is running, check the diagnosis code output.
Engine warning lamp inspection items
Engine-ECU
Air flow sensor (AFS)
Intake air temperature sensor
Throttle position sensor (TPS)
Engine coolant temperature sensor
Crank angle sensor
Camshaft position sensor
Barometric pressure sensor
Detonation sensor
Injector
Ignition coil, power transister
Misfire
1-2 METHOD OF READING AND ERASING DIAGNOSIS
CODES
(1) Use the special tool to earth No.1 terminal (diagnosis
control terminal) of the diagnosis connector.
(2) To check ABS system, remove the valve relay.
NOTE
That is because the valve relay is off and the warning
lamp remains illuminated if there is a fault in the ABS
system.
(3) Turn off the ignition switch.
(4) Read out a diagnosis code by observing how the warning
lamp flashes.
Indication of diagnosis code by warning lamp
When the diagnosis code No.24 is outputWhen no diagnosis code is output*
On
Off
1.5 secs.0.5 sec.
0.5 sec.
Pause
time 3
secs.Tens signalPlace
division
2 secs.Units signal
A03X0113
On
Off
0.5 sec.
0.25 sec.
NOTE
*: Even if the ABS system is normal, removing the valve relay causes the diagnosis code No.52 to
be output.
Engine warning lamp
(check engine lamp)

MPI – Troubleshooting13-7
1-3 ERASING DIAGNOSIS CODES
(1) Turn the ignition switch to OFF.
(2) After disconnecting the battery cable from the battery (–) terminal for 10 seconds or more, reconnect
the cable.
(3) After the engine has warmed up, run it at idle for about 15 minutes.
1-4 FAIL-SAFE FUNCTION REFERENCE TABLE
When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled
by means of the pre-set control logic to maintain safe conditions for driving.
Malfunctioning itemControl contents during malfunction
Air flow sensor (AFS)(1) Uses the throttle position sensor signal and engine speed signal (crank angle sensor
signal) to take reading of the basic injector drive time and basic ignition timing from
the pre-set mapping.
(2) Fixes the ISC servo in the appointed position so idle control is not performed.
Intake air temperature
sensorControls as if the intake air temperature is 25C.
Throttle position
sensor (TPS)No increase in fuel injection amount during acceleration due to the throttle position sensor
signal.
Engine coolant
temperature sensorControls as if the engine coolant temperature is 80C.
(This condition is maintained until the ignition switch is turned off even when the sensor signal
returns normal.)
Camshaft position
sensor(1) Injects fuel to all cylinders simultaneously for 4 seconds.
(However, after the ignition switch is turned to ON, the No. 1 cylinder top dead centre
is not detected at all.)
(2) Lets the fan motor (radiator and condensor) run at high speed.
Barometric pressure
sensorControls as if the barometric pressure is 101 kPa {760 mmHg}.
Detonation sensorSwitches the ignition timing from ignition timing for super petrol to ignition timing for standard
petrol.
Ignition coil, power
transistorCuts off the fuel supply to cylinders with an abnormal ignition.
Alternator FR terminalDoes not control the output of the alternator according to an electrical load. (works as a
normal alternator)
Misfire
(Evolution-V only)Cuts off the fuel to the misfiring cylinder if a misfire that could damage the catalyst is detected.

MPI – Troubleshooting13-8
2. INSPECTION CHART FOR DIAGNOSIS CODES
Code No.Diagnosis itemReference page
12Air flow sensor (AFS) system13-8
13Intake air temperature sensor system13-9
14Throttle position sensor (TPS) system13-9
21Engine coolant temperature sensor system13-10
22Crank angle sensor system13-11
23Camshaft position sensor system13-11
24Vehicle speed sensor system13-12
25Barometric pressure sensor system13-13
31Detonation sensor system13-14
41Injector system13-14
44Ignition coil and power transistor unit system13-15
64Alternator FR terminal system13-16
3. INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Code No. 12 Air flow sensor (AFS) systemProbable cause
Range of Check
Engine speed is 500 r/min or more.
Set conditions
Sensor output frequency is 3 Hz or less for 4 seconds.Malfunction of the air flow sensor
Improper connector contact, open circuit or
short-circuited harness wire of the air flow sensor
Malfunction of the engine-ECU
Measure at the air flow sensor con-
nector A-25.
Connect the connector. (Use
the test harness: MB991709)
1. Voltage between 3 and earth
(Engine: Idling)
OK:2.2–3.2 V
2. Voltage between 7 and earth
OK:0–1 V (Engine: idling)
6–9 V (2,000 r/min)
OK
Replace the engine-ECU.1. NG
Check the air flow sensor circuit.
2. NG
Measure at the engine-ECU con-
nector B-59.
Connect the connector.
Voltage between 19 and earth
(Ignition switch: ON)
OK:6–9 V
OK
Check the following connector:
B-59
OK
Check trouble symptom.
NG
Replace the engine-ECU.NG
Check the following connector:
A-25NG
Repair
OK
Check trouble symptom.
NG
NG
Repair
Replace the air flow sensor.

MPI – Troubleshooting13-9
Code No. 13 Intake air temperature sensor systemProbable cause
Range of Check
Ignition switch: ON
Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.
Set conditions
Sensor output voltage is 4.6 V or more (corresponding to an intake air temperature
of –45C or less) for 4 seconds.
or
Sensor output voltage is 0.2V or less (corresponding to an intake air temperature
of 125C or more) for 4 seconds.Malfunction of the intake air temperature sensor
Improper connector contact, open circuit or
short-circuited harness wire of the intake air
temperature sensor circuit
Malfunction of the engine-ECU
OK
Check trouble symptom.
Check the intake air temperature sen-
sor. (Refer to P.13-32.)NGReplace air flow sensor.
OK
Measure at the air flow sensor connec-
tor A-25.
Disconnect the connector, and
measure at the harness side.
Voltage between 6 and earth
(Ignition switch: ON)
OK:4.5–4.9 V
Continuity between 5 and earth
OK:ContinuityNGCheck the following connector:
C-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the
engine-ECU and the intake air temper-
ature sensor connector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector:
A-25NG
Repair
NG
Code No. 14 Throttle position sensor (TPS) systemProbable cause
Range of Check
Ignition switch: ON
Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.
Set conditions
The sensor output voltage is 0.2 V or less for 4 seconds.Malfunction of the throttle position sensor
Improper connector contact, open circuit or
short-circuited harness wire of the throttle position
sensor circuit
Improper “ON” state of idle position switch
Short circuit of the idle position switch signal line
Malfunction of the engine-ECU
Check the throttle position sensor.NG
Replace
OK
Measure at the throttle position sensor
connector A-16.
Disconnect the connector, and
measure at the harness side.
Voltage between 1 and earth
(Ignition switch: ON)
OK:4.8–5.2 V
Continuity between 4 and earth
OK:ContinuityNGCheck the following connector:
B-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the
engine-ECU and the throttle position
sensor connector.NG
Repair
OK
Replace the engine-ECU. OK
Check the throttle position sensor out-
put circuit.

MPI – Troubleshooting13-10
Code No. 21 Engine coolant temperature sensor systemProbable cause
Range of Check
Ignition switch: ON
Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.
Set conditions
Sensor output voltage is 4.6 V or more (corresponding to an engine coolant
temperature of –45C or less) for 4 seconds.
or
Sensor output voltage is 0.1 V or less (corresponding to an engine coolant
temperature of 140C or more) for 4 seconds.Malfunction of the engine coolant temperature sensor
Improper connector contact, open circuit or
short-circuited harness wire of the engine coolant
temperature sensor circuit
Malfunction of the engine-ECU
Range of Check
Ignition switch: ON
Engine speed is approx. 50 r/min or more
Set conditions
The sensor output voltage increases from 1.6 V or less (corresponding to an
engine coolant temperature of 40C or more) to 1.6 V or more (corresponding
to an engine coolant temperature of 40C or less).
After this, the sensor output voltage is 1.6 V or more for 5 minutes.
OK
Check trouble symptom.
Check the engine coolant temperature
sensor. (Refer to P.13-32.)NG
Replace
OK
Measure at the engine coolant temper-
ature sensor connector A-38.
Disconnect the connector, and
measure at the harness side.
Voltage between 1 and earth
(Ignition switch: ON)
OK:4.5–4.9 V
Continuity between 2 and earth
OK:ContinuityNGCheck the following connector:
B-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the
engine-ECU and the engine coolant
temperature sensor connector.NG
Repair
OK
Replace the engine-ECU.
Check the following connector:
A-38NG OK
Repair
NG