1998 MITSUBISHI LANCER EVOLUTION IV fuel

MPI – Troubleshooting13-23
Terminal
No.Normal condition Check condition (Engine condition) Check item
21Fan motor relay (LOW)Fan not operating (coolant temperature: 90C or
below)Battery voltage
Fan at low speed (coolant temperature: 90 – 100C)0 – 3 V
22A/C relayEngine: Idling
A/C switch: OFF to ON (Compressor is being
driven.)Battery voltage, or 6 V
or more instanta-
neously to 0 – 3 V
33Alternator G terminalEngine: Warm, idle (radiator fan: OFF)
Headlamp: OFF to ON
Brake lamp: OFF to ON
Rear defogger switch: OFF to ONVoltage rises by 0.2 –
3.5 V.
36Engine warning lampIgnition switch: OFF → ON0 – 3 V → Battery
voltage (After several
seconds have
elapsed)
37Power steering fluid
pressure switchEngine: Idling after
warming upWhen steering wheel is
stationaryBattery voltage
When steering wheel is
turned0 – 3 V
38Control relayIgnition switch: OFFBattery voltage
Ignition switch: ON0 – 3 V
39Fuel pump relay No.2While engine is idling, suddenly depress the
accelerator pedal.Momentarily rises
slightly from 0 to 3 V.
40Exhaust temperature
warning lampIgnition switch: OFF to ON0 – 3 V to battery
voltage (After several
seconds have
elapsed)
41Alternator FR terminalEngine: Warm, idle (radiator fan: OFF)
Headlamp: OFF to ON
Brake lamp: OFF to ON
Rear defogger switch: OFF to ONVoltage drops by 0.2 –
3.5 V.
45A/C switchEngine: Idle speedTurn the A/C switch OFF0 – 3 V
Turn the A/C switch ON
(A/C compressor is oper-
ating)Battery voltage
60Oxygen sensor heater
(Evolution V only)
Engine: Idling0 – 3 V
(Evolution-V only)
Engine speed: 5,000 r/minBattery voltage
71Ignition switch-STEngine: Cranking8 V or more

MPI – Troubleshooting13-25
6-2 RESISTANCE AND CONTINUITY BETWEEN HARNESS SIDE CONNECTORS AND
TERMINALS
Engine-ECU Harness Side Connector Terminal Arrangement
Terminal No.Inspection itemNormal condition (Check condition)
1 – 12No.1 injector2 – 3 Ω (At 20C)
14 – 12No.2 injector
2 – 12No.3 injector
15 – 12No.4 injector
3 – 12Fuel pressure control valve28 – 36 Ω (At 20C)
4 – 12Stepper motor coil (A1)28 – 33 Ω (At 20C)
17 – 12Stepper motor coil (A2)
5 – 12Stepper motor coil (B1)
18 – 12Stepper motor coil (B2)
6 – 12Secondary air control solenoid valve28 – 36 Ω (At 20C)
11 – 12Wastegate solenoid valve62 – 74 Ω (At 20C)
13 – Body earthEngine-ECU earthContinuity established (0 Ω)
26 – Body earth
60 – 12Oxygen sensor heater (EVOLUTION-V
only)11 – 18 Ω (at 20C)
72 – 92Intake air temperature sensor5.3 – 6.7 kΩ (When intake air temperature is 0C)
2.3 – 3.0 kΩ (When intake air temperature is 20C)
1.0 – 1.5 kΩ (When intake air temperature is 40C)
0.30 – 0.42 kΩ (When intake air temperature is 80C)
74 – 77High temperature sensor3 Ω or less
83 – 92Engine coolant temperature sensor5.1 – 6.5 kΩ (When coolant temperature is 0C)
2.1 – 2.7 kΩ (When coolant temperature is 20C)
0.9 – 1.3 kΩ (When coolant temperature is 40C)
0.26 – 0.36 kΩ (When coolant temperature is 80C)
87 – 92Idle position switchContinuity established (when throttle valve is at idle
position)
No continuity (when throttle valve is slightly open)
91 – Body earth–Continuity established

MPI – Troubleshooting13-27

Observation conditions
Probe selector switch× 10
AC-GND-DCDC
VOLTS/DIV.1 V
TIME/DIV.0.5 ms
Misc.–
Engine speedIdle

The power supply voltage is being normally applied and, when a signal is received from the engine
ECU, the voltage drops to around 0 V for the period of time equivalent to its drive signal.
When the signal from the engine ECU turns OFF, the counter emf of the coil causes a voltage peak
to develop, thus resuming the power supply voltage.
Injector drive time:
The fuel injection time as determined by the engine ECU according to the output values of sensors
including AFS. Injector drive time = effective injection time + invalid injection time (Invalid injection
time: corrects operation time lag caused by a power supply voltage drop)
Solenoid coil counter emf:
When the signal from the engine ECU turns OFF, counter emf occurs in the injector coil (approx.
65 to 75 V).
Power supply voltage:
The power supply voltage is being applied in the absence of a signal from the engine ECU. If this
voltage is low, it extends the invalid injection time and, thus, the drive time.

Point A: Strength of solenoid coil counter emf
Solenoid coil counter emf is low or zero.Injector solenoid shorting
Point B: Injector drive time
When the engine is suddenly raced, the drive time temporarily
extends by a wide margin and soon returns to the normal
drive time corresponding to the engine speed.
Point A
Point B
Injector
drive timeSolenoid counter emf
(approx. 7 × 10 V)
Power supply voltage
At idle
During racing

MPI – Troubleshooting13-28
Injector Power Supply Voltage (Oscilloscope 2)

(1) Disconnect the resistor connector and connect the special
tool (Harness Connector: MD998463) to the circuit.
(2) Connect the oscilloscope probe to resistor connector
terminal (1) (special tool red clip) when the waveform
is observed with no. 1 cylinder, to terminal (4) (black
clip) when the waveform is observed with no. 2 cylinder,
to terminal (5) (green clip) when the waveform is observed
with no. 3 cylinder, and to terminal (6) (yellow clip) when
the waveform is observed with no. 4 cylinder.
(3) For the power supply voltage, observe the waveform of
the injector control signal at the same time. (Refer to
P.13-26 for the injector control signal measurement
procedure.)

Observation conditions
Injector power supply voltage waveformInjector control signal
Probe selector switch× 1× 10
AC-GND-DCACDC
VOLTS/DIV.5 V1 V
TIME/DIV.0.5 ms
Misc.To be timed with injector control signal
Engine speedIdle (850 rpm)
Injector power supply
voltage waveform
(oscilloscope 2)
Injector control signal
waveform
(oscilloscope 1)Plunger in fully
opened position
Point B
Point A
Fuel injection time
Time

MPI – Troubleshooting13-29

The injector power supply voltage waveform shows a voltage drop caused by resistance of the resistor.
As the amount of current increases, voltage gradually decreases and a spike occurs at the plunger fully
opened position due to counter emf.

Point A: Voltage drop during fuel injection time (Refer to abnormal waveform example 1.)
Difference from standard waveformPossible cause
Voltage drop during fuel injection time is small (there
should normally be a voltage drop of about 10 V).Resistance of resistor is too small. Resistance of injector
is too large.
Point B: Spike when plunger is fully open (Refer to abnormal waveform example 2.)
Difference from standard waveformPossible cause
No spike when plunger is fully openPlunger inoperative

Example 1
[Cause of problem]
Resistance of the resistor is too small.
[Waveform characteristics]
Small voltage drop
Example 2
[Cause of problem]
Plunger is inoperative.
[Waveform characteristics]
No spike when plunger is fully open.
7-4 IGNITION COIL
Perform the same steps as with the conventional 4G9 engine
for the inspection.
Abnormal waveform
Normal waveform

MPI – On-vehicle Service13-30
ON-VEHICLE SERVICE
1. IDLE POSITION SWITCH AND THROTTLE
POSITION SENSOR (TPS) ADJUSTMENT
The thickness of the feeler gauge inserted between the fixed
SAS and throttle lever should be 0.45 mm.
2. FIXED SAS ADJUSTMENT

Turn down one turn after the fixed SAS has touched the
throttle lever.

Turn down 1-1/4 turns after the fixed SAS has touched the
throttle lever.
3. BASIC IDLE SPEED ADJUSTMENT
The basic idle speed should be 850 ± 50 rpm.
4. FUEL PRESSURE MEASUREMENT
The fuel pressure gauge should be installed at the location
shown on the left.

MPI – On-vehicle Service13-31
5. MPI SYSTEM COMPONENTS LAYOUT
NameSymbolNameSymbol
A/C switchQExhaust temperature warning lampS
A/C relayHFuel pressure control valveA
Air flow sensor (with a built-in intake air temperaturesensor and barometric pressure sensor)FIgnition coil and power transistor unitLsensor and barometric pressure sensor)InjectorB
Camshaft position sensorMISC servoD
Control relay and fuel pump relayPOxygen sensorK
Coolant temperature sensorEPower steering fluid pressure switchI
Crank angle sensorJSecondary air control solenoid valveN
Detonation sensorCThrottle position sensor (with a built-in idle switch)D
Diagnosis connectorR
Engine ECUOVehicle speed sensorT
Engine warning lampSWastegate solenoid valveG

MPI – On-vehicle Service13-33
(2) Check that there is continuity (11 to 18 Ω at 20C) across
terminal no. 1 (special tool red clip) and terminal no. 3
(special tool blue clip) of the oxygen sensor connector.
(3) If there is no continuity, replace the oxygen sensor.
(4) Run the engine until the engine coolant temperature
exceeds 80C.
(5) Using jumper wires, connect oxygen sensor terminal no.
1 (special tool red clip) and terminal no. 3 (special tool
blue clip) to battery (+) and (–) terminal, respectively.
Caution
Make sure of the correct connections: if a wrong
connection is made, a broken oxygen sensor results.
(6) Connect a digital voltmeter between terminal no. 2 (special
tool black clip) and terminal no. 4 (special tool white clip).
(7) Race the engine repeatedly to measure the oxygen sensor
output voltage.
Standard value:
EngineOxygen sensor
output voltageNOTE
When
engine is
raced0.6 – 1.0 VWhen engine racing is
repeated to enrich air-fuel
ratio, an operational oxygen
sensor should output a volt-
age of 0.6 to 1.0 V.
NOTE
Use the same procedures to remove and install the oxygen
sensor.
Red clip
Blue clip
MD998464
Red clip
Blue clip
MD998464 Black clip
White clip