Mitsubishi Lancer (4A9 engine). Manual — part 25

ON-VEHICLE SERVICE

ENGINE MECHANICAL <4A9>

11A-14

IDLE MIXTURE CHECK

M1111002102068

AC608435

MB991827

MB991824

MB991910

AB

Diagnosis connector

<LH drive vehicles>

AC700191

MB991827

MB991824

AB

Diagnosis connector

<RH drive vehicles>

MB991910

1. Before inspection, set the vehicle to the pre-

inspection condition.

2. Turn the ignition switch to "LOCK" (OFF) position.
3. Connect the M.U.T.-III to the diagnosis connector.

AK802816

3

2

1

No.1 Ignition coil

AB

Power supply line
(terminal No. 3)

Equipment side
connector

4. Set the timing light to the power supply line

(terminal No. 3) of the ignition coil No. 1.
NOTE: The power supply line is looped and also
longer than the other ones.

5. Start the engine and let it run at idle.
6. Check that ignition timing is at the standard value.

Standard value: approximately 10

° BTDC

NOTE:

.

•

The ignition timing may fluctuate within

±

7

°

. This

is normal.

•

In higher altitude, the ignition timing is more
advanced than the standard value by approxi-
mately 5

°

.

•

Wait till approximately 1 minute passes after the
engine started, and check the ignition timing
when the engine stabilized.

7. Run the engine at 2,000

− 3,000 r/min for 2

minutes.

8. Set the CO, HC tester.
9. Check the CO contents and the HC contents at

idle.

Standard value

CO contents: 0.3 % or less
HC contents: 200 ppm or less

10.If there is a deviation from the standard value,

inspect the MPI system (Refer to GROUP 13A

−

Troubleshooting

− Inspection Chart for Trouble

Symptoms )

11.Remove the timing light and CO, HC tester.
12.Turn the ignition switch to "LOCK" (OFF) position

and then disconnect the M.U.T.-III.

VALVE CLEARANCE CHECK AND
ADJUSTMENT

M1111001501930

NOTE: Perform the valve clearance check and
adjustment at the engine cold state.
1. Remove all ignition coils.
2. Remove the cylinder head cover.

ON-VEHICLE SERVICE

ENGINE MECHANICAL <4A9>

11A-15

CAUTION

Turn the crankshaft always clockwise.

AK306138AB

Timing mark

3. Turn the crankshaft clockwise, and align the

timing mark on the exhaust camshaft sprocket
against the upper face of the cylinder head as
shown in Figure. Therefore, No.1 cylinder goes to
the compression top dead centre.

AK305589

Exhaust valve side

No. 1

No. 1

No. 3

No. 2

Intake valve side

AB

4. Using a thickness gauge, measure the valve

clearance with the arrow shown in Figure. If
deviated from the standard value, make note for
the valve clearance.

Standard value:

Intake valve 0.22

± 0.04 mm

Exhaust valve 0.30

± 0.04 mm

AK306139AB

Timing mark

5. Turn the crankshaft clockwise 360 degrees, and

put the timing mark on the exhaust camshaft
sprocket in position shown in Figure. Therefore,
No.4 cylinder goes to the compression top dead
centre.

AK305589

Exhaust valve side

No. 2

No. 3

No. 4

No. 4

Intake valve side

AC

6. Check the valve clearance with the arrow shown

in Figure. In the same procedure as 4.

7. If the valve clearance is deviated from the

standard value, remove the camshaft and the
valve tappet. For the camshaft removal, refer to
Camshaft Removal and Installation .

AK304938

AB

Wall
thickness

8. Using a micrometer, measure the thickness of the

removed valve tappet.

9. Calculate the thickness of the newly installed

valve tappet through the following equation.
A: thickness of newly installed valve tappet
B: thickness of removed valve tappet
C: measured valve clearance

Equation

Intake valve: A = B + (C

− 0.22 mm)

Exhaust valve: A = B + (C

− 0.30 mm)

ON-VEHICLE SERVICE

ENGINE MECHANICAL <4A9>

11A-16

NOTE:

AK305693

Identification mark

AB

The valve tappet ranges 5.10

−

5.70 mm and has

31 types per 0.02 mm. The thickness below a
decimal point is stamped on the reverse side of
the valve tappet.
Example: In case of 5.40 mm, "40" is stamped.

10.Install the valve tappet selected through the

procedure 10, and put the camshaft in position.
For the camshaft installation, refer to Camshaft
Removal and Installation .

11.Remove any liquid gasket remaining on the

cylinder head cover, the timing chain case and the
cylinder head.

AK304933AB

CAUTION

The cylinder head cover should be installed
within 3 minutes of applying liquid gasket.
12.Apply a 4 mm bead of liquid gasket as illustrated.

Specified sealant:

Three bond 1217G or exact equivalent

AK401050

AB

4

8

5

10

2

6

9

1

7

3

Timing chain side

13. Install the cylinder head cover and tighten the

tightening bolts using the following procedures.
(1) Temporarily tighten to the following torque in

order shown in the illustration.

Tightening torque: 3.0

± 1.0 N⋅m

(2) Tighten to the specified torque in order shown

in the illustration.

Specified torque: 5.5

± 0.5 N⋅m

14.Install the ignition coils.

COMPRESSION PRESSURE CHECK

M1111002603754

1. Before inspection, set the vehicle to the pre-

inspection condition.

2. Remove all of the ignition coils and spark plugs.

AK305808AB

Injector connectors

3. Disconnect the all of the injector connectors.

CAUTION

• Keep away from the spark plug hole when

cranking.

• If compression is measured with water, oil,

fuel, etc., that has come from cracks inside
the cylinder, these materials will become
heated and will gush out from the spark plug
hole, which is dangerous.

4. Cover the spark plug hole with a shop towel etc.,

and after the engine has been cranked, check that
no foreign material is adhering to the shop towel.

AK305516AB

Compression gauge

5. Set compression gauge to one of the spark plug

holes.

ON-VEHICLE SERVICE

ENGINE MECHANICAL <4A9>

11A-17

6. Cranking the engine with the accelerator pedal

fully depressed, measure the compression
pressure.

<4A91>

Standard value (at engine speed of 300 r/min):

1,550 kPa

Limit (at engine speed of 300 r/min): Minimum

1,050 kPa
<4A92>

Standard value (at engine speed of 250 r/min):

1,550 kPa

Limit (at engine speed of 250 r/min): Minimum

1,050 kPa

7. Measure the compression pressure for all the

cylinders, and check that the pressure differences
of the cylinders are below the limit.

Limit: Maximum 98 kPa

8. If there is a cylinder with compression or a

compression difference that is outside the limit,
pour a small amount of engine oil through the
spark plug hole, and repeat the operations in
steps from 5 to 7.
(1) If the compression increases after oil is added,

the cause of the malfunction is a worn or
damaged piston ring and/or cylinder inner
surface.

(2) If the compression dose not rise after oil is

added, the cause is a burnt or defective valve
seat, or pressure is leaking from the gasket.

9. Connect the crank angle sensor connector.
10.Install the spark plugs and spark plug cables.
11.Use the M.U.T.-III to erase the diagnosis codes.

NOTE: This will erase the diagnosis code result-
ing from the injector connectors being discon-
nected.

MANIFOLD VACUUM CHECK

M1111002702457

AC608435

MB991827

MB991824

MB991910

AB

Diagnosis connector

<LH drive vehicles>

AC700191

MB991827

MB991824

AB

Diagnosis connector

<RH drive vehicles>

MB991910

1. Before inspection, set the vehicle to the pre-

inspection condition.

2. Turn the ignition switch to "LOCK" (OFF) position.
3. Connect the M.U.T.-III to the diagnosis connector.