Engine - High Altitude Modifications
86mitsubishi03
SUBJECT:
HIGH ALTITUDE MODIFICATIONS - 1987 TRUCKS AND MONTEROS
NO. STB-86-25-004 REVISION
DATE October, 1986
MODEL 1987 Truck, Montero
NOTE: This bulletin supersedes STB-86-25-004 dated September 1986 which is invalid and should be discarded. The modification procedure has been changed, and the time allowance has been increased.
PURPOSE
1987 Trucks and Monteros distributed to high-altitude market areas must be modified for high-altitude operation by the dealer before sale. Modifications consist of advancing the ignition timing and installing a High Altitude Compensator, distributor vacuum advance mechanism, and underhood label.
VEHICLES TO BE MODIFIED
1987-Model Trucks and Monteros, 2-wheel drive and 4-wheel drive models, 2.0 and 2.6L engines, GEOGRAPHIC APPLICATION
If a 1987 vehicle's ultimate intended use is in one of the following high altitude states and counties, it must be equipped with a high altitude kit.
HIGH-ALTITUDE STATES AND COUNTIES - 1987 MODELS
State of Arizona
Apache Navajo
Cochise Yavapai
Coconino
State of Colorado All counties
State of Idaho
Bannock Franklin
Bear Lake Fremont
Bingham Jefferson
Blaine Lemhi
Bonneville Madison
Buffe Minidoka
Camas Oneida
Caribou Power
Cassia Teton
Clark Valley
Custer
State of Montana
Beaverhead Madison
Deer Lodge Meagher
Gallatin Park
Jefferson Silver Bow
Judith Basin Wheatland Powell
State of Nebraska
Banner Kimball
Cheyenne Sioux
State of Nevada All counties
State of New Mexico All counties
State of Oregon
Harney Klamath
Lake
State of Texas
Jeff Davis Parmer
Hudspeth
State of Utah All counties
State of Wyoming
Albany Notrona
Campbell Niobrara
Carbon Park
Converse Plate
Fremont Sublete
Goshen Sweetwater
Hot Springs Teton
Johnson Uinto
Laramie Washakie
Lincoln Weston
WARRANTY INFORMATION
Labor Operation Code: 25 05 30 01
Time Allowance: 0.7 hr.
PARTS REQUIRED
Five kits are available:
MD114741 for 2.0L Manual-Transmission Trucks
MD114742 for 2.0L Automatic-Transmission Trucks
MD114743 for 2.6L Trucks w/o 2000 Lb payload
MD114744 for 2.6L 2000 Lb payload and 4WD Trucks
MD114745 for Monteros
Components of the above kits are listed in the table below:
1987 MODEL HIGH-ALTITUDE KIT NUMBERS AND COMPONENTS
MODIFICATION PROCEDURE
1. Replace the distributor vacuum assembly as described in the Service Manual.
2. Set ignition timing to specifications for the two engine with distribution vacuum hose disconnected and plugged as follows:
Engine
2.0L 8~ BTDC
2.6L 7~ BTDC
FIGURE 3 - INSTALLATION OF HAC & VACUUM HOSE ASSY (APPLICABLE TO TRUCK 2.0-LITER):
FIGURE 4 - INSTALLATION OF HAC & VACUUM HOSE ASSY (APPLICABLE TO TRUCK & TRUCK (4WD), 2.6-LITER):
FIGURE 5 - INSTALLATION OF HAC & VACUUM HOSE ASSY (APPLICABLE TO MONTERO, 2.6-LITER):
FIGURE 6 - VEHICLE EMISSION CONTROL INFORMATION UPDATE LEVEL:
3. Replace the distributor vacuum assembly as described in the Service Manual.
4. Install the High Altitude Compensator and hoses as follows:
a. Install the HAC bracket on the Device Box in the engine compartment. See Fig. 3, 4, and 5.
b. Remove the rubber caps from the carburetor and Device Box (Fig. 3, 4, and 5.)
c. Install the vacuum hoses as indicated in the appropriate illustration.
5. Apply the Vehicle Emissions Control Information Update Label (Fig. 6) on the underside of the hood In the location shown in Fig. 2.
PROCEDURE CLARIFICATION
Before checking ignition timing, remove the distributor vacuum hoses and plug them. Then set Ignition timing to the specifications given above. When the hoses are re-connected, the High Altitude Compensator (HAC) will automatically advance the timing approximately 5~ at high altitudes.
Legend: 1. High-Altitude Compensator (HAC)
2. HAC Bracket
3. Bolt/Washer Assembly
4. Vacuum Hose
5. Distributor Vacuum Assembly
6. Vehicle Emission Control Information Update Label