Mitsubishi Lancer Evolution 8. Manual — part 178
MPI – TROUBLESHOOTING
13A-98
<Abnormal waveform>
• Example 1
Waveform characteristics
Motor turning induced electromotive force is absent.
Cause of fault
Motor malfunction (motor is not turning)s
• Example 2
Waveform characteristics
Current is not supplied to the motor coil on the open circuit side. (Voltage
does not drop to 0V).
Furthermore, the induced electromotive waveform on the normal side is
slightly different to the standard waveform.
Cause of fault
Circuit is broken between the motor and engine ECU.
10-5 Ignition coil (power transistor control signal)
<Measurement Method>
(1) Undo ignition coil connector, then connect special harness
(MBB991658). (All terminals should be connected)
(2) Connect oscilloscope probe to ignition coil connector terminal No.3.
Note
When doing engine ECU connector measurement, connect the
oscilloscope probe to terminal No.11 (Ignition coil Nos.1 and 4), terminal
No.12 (Ignition coil Nos.2 and 3).
(3) To check ignition advance condition, simultaneously observe crank
angle sensor output signal.
<Standard waveform>
Observation conditions
Open
circuit
side
Normal
side
Oscilloscope
Power transistor control signal
Crank angle sensor
Probe switch
x1
x1
AC-GND-DC
DC
DC
VOLTS/DIV.
2V
2V
TIME/DIV.
10ms
10ms
Other
-
-
Engine speed
About 1,200 rpm
MPI – TROUBLESHOOTING
13A-99
Standard waveform
<Explanation of waveform>
• When spark angle is advanced by, for example, engine speed increasing, conditions such as those illustrated above arise.
Ignition advance angle
θ
= 75° - T1 / T x 180°
• Power transistor ON
Condition where the power transistor is turned ON, and ignition coil primary side is powered (Dwell Section). The time it is
powered will be shorter when the battery voltage is high, and it will be controlled so that the primary current at the time of
ignition stabilises (about 6A). (The waveform for this section will be rising to the right)
• Power transistor OFF
With the power transistor OFF, the power transistor drive signal is not output from the engine ECU.
<Waveform Observation Points>
• Waveform starting point condition and maximum voltage (ref. Abnormal waveform Examples 1, 2)
<Abnormal waveform>
• Example 1
Waveform when engine cranking
Waveform characteristics
At start up point, wave does not move upwards to the right, and the voltage
is low at about 2V.
Cause of fault
Ignition primary circuit open
• Example 2
Waveform during engine cranking
Waveform characteristics
There is a power supply voltage when the power transistor is ON.
Cause of fault
Power transistor fault.
Crank angle sensor
Output waveform
Power transistor
control signal
waveform
Top Dead Centre
Ignition timing
T: Crank angle
T1: Time calculated by engine
ECU
θ
: Ignition advance angle
Dwell section
Normal waveform
Normal waveform
Waveform starting point condition and maximum voltage
Possible causes
Rises, upwards and to the right, up to about 4.5V from about 2V Normal
Rectangular wave about 2V
Ignition primary circuit open
Power supply voltage rectangular wave
Power transistor fault
MPI <4G6> - INJECTORS
13A-100
INJECTORS
Disassembly and reassembly
Work that needs to be done before disassembly and after assembly
• Measures to prevent fuel escaping (only prior to removal)
• Removal and fitting of strut tower bar
• Removal and fitting of air hose E, air by-pass hose, and air pipe C (ref. Chapter 15 Intercooler)
• Check for any fuel leaks (only after fitting)
Engine oil
MPI <4G6> - FUEL INJECTORS
13A-101
Disassembly procedure
1. Vacuum hose connection
2. PCV hose connection
3. Control harness clamp connection
4. Throttle cable connection
(throttle body side)
5. Injector harness connector
6. Fuel return hose connection
7. Fuel high pressure hose connection
8. O-ring
9. Vacuum hose connection
10. Fuel return hose
11. Fuel pressure regulator
12. O-ring
13. Fuel return pipe
14. Delivery pipe
15. Insulator
16. Insulator
17. Injector
18. O-ring
19. Grommet
Disassembly service points
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Delivery pipe/injector removal
Remove the delivery pipe with the injector attached.
Assembly service points
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Assembling injectors/fuel pressure regulator/fuel high pressure
hose
1. Apply a small quantity of new engine oil to O-ring
2. Being careful not to damage it, fit O-ring to delivery pipe whilst rotating fuel
pressure regulator, and fuel high pressure hose, to left and right, making sure
that you rotate them smoothly.
3. If they are not rotated smoothly, the O-ring could be pinched, so remove the
part and check the O-ring for any damage, then re-insert into delivery pipe
and check.
4. Tighten fuel pressure regulator to specified torque.
Tightening torque: 8.9 ± 1.9 N·m
5. Tighten fuel high pressure hose to specified torque.
Tightening torque: 5.0 ± 1.0 N·m
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