Mitsubishi Montero (1991+). Manual — part 35

D - ADJUSTMENTS

1991 Mitsubishi Montero

1991 ENGINE PERFORMANCE

On-Vehicle Adjustments

Chrysler Motors: Colt, Colt 200, Colt Vista,

Ram-50, Stealth, Summit

Mitsubishi: Eclipse, Galant, Mirage, Montero,

Pickup, 3000GT

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or

ignition system, ensure engine mechanical condition is okay.

VALVE CLEARANCE

NOTE: All engines except 1.5L use hydraulic valve lifters. Valve

adjustment is only required on 1.5L engines. To check

hydraulic valve lifter operation, see CHECKING HYDRAULIC

VALVE LIFTERS.

MECHANICAL VALVE LIFTERS

CAUTION: DO NOT rotate crankshaft in opposite direction of normal

engine rotation.

1.5L

1) Ensure engine is at normal operating temperature. Remove

all spark plugs and valve cover. Rotate crankshaft to position

cylinder No. 1 on TDC of compression stroke. Adjust intake valves on

cylinders No. 1 and No. 2, and exhaust valves on cylinders No. 1 and

No. 3. See VALVE CLEARANCE ADJUSTMENT table for specification.

2) Rotate crankshaft 360 degrees to position cylinder No. 4

on TDC of compression stroke. Adjust intake valves on cylinders No. 3

and No. 4, and exhaust valves on cylinders No. 2 and No. 4.

VALVE CLEARANCE ADJUSTMENT TABLE

Cold Hot

Application In. (mm) In. (mm)

Intake . . . .003 (.07) . . . .006 (.15)

Exhaust . . ... .007 (.17) . . . .010 (.25)

CHECKING HYDRAULIC VALVE LIFTERS

Except 1.5L

1) Remove valve cover. Push downward on end of rocker arm

above lash adjuster. If lash adjuster is normal, it will feel hard. If

lash adjuster moves downward easily when pushed, replace adjuster.

2) If lash adjuster feels soft or spongy, oil with air has

probably entered lash adjuster. If this occurs, check engine oil

level. If engine oil level is okay, check oil screen and oil screen

gasket for damage.

3) After repairing cause of air leak, warm engine to

operating temperature. Drive vehicle at low speed for approximately 5

minutes. Turn engine off for a few minutes.

4) Restart engine and drive at low speed for approximately 5

minutes. Repeat this step several times for about one hour. This helps

remove air from engine oil.

IGNITION TIMING

NOTE: Perform all adjustments with engine at normal operating

temperature, cooling fan and accessories off, transmission

in Park or Neutral, and front wheels in straight-ahead

position. Set curb idle speed to specification. See IDLE

SPEED SPECIFICATIONS table under IDLE SPEED & MIXTURE.

IGNITION TIMING

1) Locate ignition timing adjustment connector. See IGNITION

TIMING ADJUSTMENT CONNECTOR LOCATION table. Connect jumper wire

between ignition timing adjustment connector and ground. Check

ignition basic timing.

2) If ignition basic timing is not within specification,

loosen distributor (or crank angle sensor on engines with dual coil

assembly) and rotate to adjust timing if necessary. See IGNITION

TIMING SPECIFICATIONS table. Disconnect jumper wire from ignition

timing adjustment connector.

IGNITION TIMING SPECIFICATIONS TABLE (Degrees BTDC@RPM)

Application (1) Basic (1) (2) Actual

1.5L

Colt, Colt 200

Mirage & Summit . ... 5@650-850 . . 10@650-850

1.6L

Mirage . . . . . 5@650-850 . . . 8@650-850

1.8L

Eclipse . . . . 5@600-800 . . 10@600-800

2.0L

Colt Vista &

Galant (VIN V) . . 5@600-800 . . 10@600-800

Eclipse . . . . 5@650-850 . . . 8@650-850

Galant

(VIN R) . . . ... 5@650-850 . . . 8@650-850

(VIN U) . . . ... 5@650-850 . . 12@650-850

2.4L

Pickup & Ram-50 . . 5@650-850 . . . 8@650-850

3.0L

Montero, Pickup, Ram-50

Stealth & 3000GT . .. 5@600-800 . . 15@600-800

(1) - Transmission in Park or Neutral.

(2) - Actual timing may fluctuate.

IGNITION TIMING ADJUSTMENT CONNECTOR LOCATION TABLE

Application (1)(2) Wire Color Location

Colt, Colt Vista, Colt 200,

Mirage & Summit

1.5L, 1.6L & 2.0L . . . . Yellow/Red . . . . (3)

Eclipse

1.8L & 2.0L (Except Turbo) . . Yellow/Red . . . . (4)

2.0L Turbo . . . . . ... Yellow/Black . . . (4)

Galant

2.0L . . . . . . . .. Yellow/Red . . . . (5)

Montero

3.0L . . . . . . . . White/Yellow . . . (4)

Pickup & Ram-50

2.4L . . . . . . . .. Black/Blue . . . . (6)

3.0L . . . . . . . . White/Yellow . . . (6)

Stealth (SOHC)

3.0L . . . . . . . . White/Yellow . . . (4)

Stealth & 3000GT (DOHC)

3.0L (Non-Turbo) . . . . . Black/Green . . . . (4)

3.0L (Turbo) . . . . . . White/Yellow . . . (4)

(1) - Remove waterproof female connector (if equipped) for access to

wire.

(2) - Ground connector at wire end for basic timing adjustment.

(3) - On main wiring harness, near center of firewall.

(4) - On main wiring harness, near wiper motor on firewall.

(5) - On main wiring harness, near master cylinder on firewall.

(6) - Between right shock tower and firewall.

(7) - Near front of right shock tower.

IDLE SPEED & MIXTURE

NOTE: Perform adjustments with engine at normal operating

temperature, cooling fan and accessories off, transmission

in Park or Neutral, and front wheels in straight-ahead

position.

CURB (SLOW) IDLE SPEED

NOTE: Curb idle speed is controlled by Idle Speed Control (ISC)

motor. Adjustment is usually not necessary. For curb idle

speed specifications, see IDLE SPEED SPECIFICATIONS table

under BASIC IDLE SPEED.

1) Check ignition timing and adjust if necessary. Run engine

at 2000-3000 RPM for more than 5 seconds. Allow engine to idle for 2

minutes. Check curb idle speed.

2) If curb idle speed is not within specification, check ISC

system. If ISC system is okay, adjust basic idle speed. See BASIC IDLE

SPEED.

BASIC IDLE SPEED

NOTE: ALWAYS check TPS adjustment after adjusting basic idle

speed. See THROTTLE POSITION SENSOR (TPS).

BASIC IDLE SPEED TEST APPLICATION TABLE

Application Test

1.5L

Colt, Colt 200,

Mirage & Summit . . . . TEST NO. 1

1.6L

Mirage . . . . . ... TEST NO. 2

1.8L

Eclipse . . . . . .. TEST NO. 1

2.0L (VIN V)

Colt Vista & Galant . . .. TEST NO. 1

2.0L (VIN R & U)

Eclipse & Galant . . . . TEST NO. 2

2.4L

Pickup & Ram-50 . . . .. TEST NO. 1

3.0L

Montero, Pickup, Ram-50,

Stealth & 3000GT . . . TEST NO. 2

Test No. 1

1) Loosen throttle cable. Turn ignition on for more than 15

seconds. DO NOT start engine. Turn ignition off. This should fully

retract ISC motor plunger.

2) On 2.0L Galant (VIN V), connect jumper wire between

ignition timing adjustment connector and ground. See IGNITION TIMING

ADJUSTMENT CONNECTOR LOCATION table under IGNITION TIMING.

3) On all models, disconnect harness connector(s) from Idle

Speed Control (ISC) motor. Ensure ISC plunger is in fully retracted

position. Unscrew fixed Speed Adjusting Screw (SAS) until throttle

valve is fully closed. See Fig. 1.

CAUTION: When cleaning throttle body, plug air by-pass hole in

throttle body to prevent solvent from entering passage.

4) Start engine. Check basic idle speed. See IDLE SPEED

SPECIFICATIONS table. If basic idle speed is within specification, go

to step 7). If basic idle speed is not within specification, remove

air intake hose and clean throttle body. Reconnect air intake hose.

Recheck basic idle speed.

5) If basic idle speed is still not within specification

after cleaning throttle body, adjust basic idle speed by turning idle

speed adjusting screw. See Fig. 1. After adjusting basic idle speed,

turn fixed SAS screw clockwise until engine speed begins to increase.

6) Turn fixed SAS screw counterclockwise until engine speed

decreases. Turn fixed SAS screw counterclockwise an additional 1/2

turn from point at which engine speed no longer decreases. Turn off

engine.

7) Adjust throttle cable. Reconnect harness connector(s) at

ISC motor. Start engine. Operate engine for about 5 minutes. Ensure

engine idles within curb idle speed specification. See IDLE SPEED

SPECIFICATIONS table.

8) Turn ignition off. Disconnect negative battery cable for

at least 10 seconds to clear diagnostic trouble code. Reconnect

negative battery cable. Operate engine at idle for about 5 minutes to

ensure engine idles smoothly.

Test No. 2

1) Locate ignition timing adjustment connector. See IGNITION

TIMING ADJUSTMENT CONNECTOR LOCATION table under IGNITION TIMING.

Connect jumper wire between ignition timing adjustment connector and

ground.

2) Locate diagnostic connector under instrument panel.

Connect jumper wire between diagnostic connector terminal No. 10

(White wire) and ground. See Fig. 3. Start engine. Check basic idle

speed. See IDLE SPEED SPECIFICATIONS table. If basic idle speed is

within specification, go to step 9). If basic idle speed is not within

specification, go to step 3).

3) Remove air intake hose. Check throttle body. If throttle

body contains deposits, go to next step. If throttle body is clean,

disconnect jumper wires connected in steps 1) and 2). On all models

except Eclipse, Galant and Mirage, go to step 6). On Eclipse, Galant

and Mirage, go to step 5).

CAUTION: When cleaning throttle body, plug air by-pass hole in