Mitsubishi Montero (2004+). Manual - part 101

ON-VEHICLE SERVICE

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ENGINE MECHANICAL

11A-9

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
2. Connect scan tool MB991958 to the data link connector.
3. Check the basic ignition timing.

Standard value: 5

° BTDC ± 3°

4. Start the engine.
5. Run the engine at idle for 2 minutes.
6. Check the idle speed. Select item number 22 and take a

reading of the idle speed.

Curb idle speed: 700

± 100 r/min

NOTE: The idle speed is controlled automatically by the idle
air control system.

7. If the idle speed is outside the standard value, refer to

GROUP 13A, Multiport Fuel Injection (MFI)

− Multiport Fuel

Injection (MFI) Diagnosis

− Symptom Chart

P.13A-30

IDLE MIXTURE CHECK

M1111002100352

Required Special Tool:
MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

1. Before checks, set the vehicle in the following condition:

• Engine coolant temperature: 80 − 95°C (176 − 203°F)

• Lights and all accessories: OFF

• Transmission: P range

NOTE: Vehicles for Canada, the headlight, taillight, etc.
remain lit even when the lighting switch is in "OFF" position
but this is no problem for checks.

AK302970

MB991911

MB991824

MB991827

ON-VEHICLE SERVICE

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ENGINE MECHANICAL

11A-10

CAUTION

value.

Standard value: 5

° BTDC ± 3°

4. Start the engine and increase the engine speed to 2,500

r/min for 2 minutes.

5. Set the CO, HC tester.
6. Check the CO contents and the HC contents at idle.

Standard value:

CO contents: 0.5% or less
HC contents: 100 ppm or less

7. If the CO and HC contents do not remain inside the standard

value, check the following items:
NOTE: Replace the catalytic converter when the CO and HC
contents do not remain inside the standard value, even
though the result of the inspection is normal for all items.

• Diagnostic output

• Closed-loop control (When the closed-loop control is carried

out normally, the output signal of the heated oxygen sensor
changes between 0

− 400 mV and 600 − 1,000 mV at idle.)

• Fuel pressures

• Injector

• Ignition coil, spark plug cable, spark plug

• Exhaust gas recirculation system and EGR valve leak

• Evaporative emission system

• Compression pressure

COMPRESSION PRESSURE CHECK

M1111002600540

1. Before checks, check that the engine oil, starter and battery

are normal. Also, set the vehicle in the following condition:

• Engine coolant temperature: 80 − 95°C (176 − 203°F)

• Lights and all accessories: OFF

• Transmission: P range

NOTE: Vehicles for Canada, the headlight, taillight, etc.
remain lit even when the lighting switch is in "OFF" position
but this is no problem for checks.

2. Disconnect the spark plug cables.
3. Remove all of the spark plugs.

AK302970

MB991911

MB991824

MB991827

ON-VEHICLE SERVICE

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ENGINE MECHANICAL

11A-11

4. Disconnect the crankshaft position sensor connector.

NOTE: Doing this will prevent the engine control module
from carrying out ignition and fuel injection.

WARNING

Keep your distance from the spark plug hole when
cranking. Oil, fuel, etc., may spray out from the spark
plug hole and may cause serious injury.

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

cranking. After the engine has been cranked, check for
foreign material adhering to the shop towel.

6. Set compression gauge to one of the spark plug holes.
7. Crank the engine with the throttle valve fully open and

measure the compression pressure.

Standard value (at engine speed of 250

− 400 r/min):

1,548 kPa (225 psi)
Minimum limit (at engine speed of 250

− 400 r/min):

1,117 kPa (162 psi)

8. Measure the compression pressure for all the cylinders, and

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

Limit: 98 kPa (14 psi)

9. 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 6 to 8.

(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 does not rise after oil is added, the

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

10.Connect the crankshaft position sensor connector.
11.Install the spark plugs and spark plug cables.
12.Use the scan tool to erase the diagnostic trouble codes.

NOTE: This will erase the diagnostic trouble code resulting
from the crankshaft position sensor connector being discon-
nected.

MANIFOLD VACUUM CHECK

M1111002700495

1. Start the engine and allow it to warm up until the

temperature of the engine coolant reaches 80

− 95°C (176 −

203

°F).

2. Connect an engine tachometer.

AK200795 AB

CRANKSHAFT
POSITION
SENSOR
CONNECTOR

AKX00436

COMPRESSION
GAUGE

ON-VEHICLE SERVICE

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ENGINE MECHANICAL

11A-12

3. Attach a tee-fitting union to the vacuum hose between the

fuel pressure regulator and the intake manifold plenum, and
connect a vacuum gauge.

4. Start the engine and check that idle speed is within

specification. Then check the vacuum gauge reading.

Idle speed: 700

± 100 r/min

Minimum limit: 60 kPa (18 in Hg)

LASH ADJUSTER CHECK

M1111002900411

If an abnormal noise (chattering noise) suspected to be caused
by malfunction of the lash adjuster is produced immediately
after starting the engine and does not disappear, perform the
following check.
NOTE: An abnormal noise due to malfunction of the lash
adjuster is produced immediately after starting the engine and
changes with the engine speed, irrespective of the engine load.
If, the abnormal noise is not produced immediately after start-
ing the engine or does not change with the engine speed, or it
changes with the engine load, the lash adjuster is not the cause
for the abnormal noise.
NOTE: When the lash adjuster is malfunctioning, the abnormal
noise is rarely eliminated by continuing the warming-up of the
engine at idle speed.
However, the abnormal noise may disappear only when seizure
is caused by oil sludge in the engine whose oil is not main-
tained properly.
1. Start the engine.
2. Check if the abnormal noise produced immediately after

starting the engine, changes with the change in the engine
speed.
If the abnormal noise is not produced immediately after
starting the engine or it does not change with the engine
speed, the lash adjuster is not the cause for the noise.
Therefore, investigate other causes. The abnormal noise is
probably caused by some other parts than the engine proper
if it does not change with the engine speed. (In this case, the
lash adjuster is in good condition.)

3. With the engine idling, change the engine load (shift from N

to D range, for example) to make sure that there is no
change in the level of abnormal noise.
If there is a change in the level of abnormal noise, suspect a
tapping noise due to worn crankshaft bearing or connecting
rod bearing (In this case, the lash adjuster is in good
condition.).

4. After completion of warm-up, run the engine at idle to check

for abnormal noise.

AK200796

VACUUM GAUGE

AK200796AB

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