ALTITUDE REQUIREMENTS ADJUSTMENT INFORMATION
New Federal emissions regulations applicable to 1982 model year vehicles contain requirements for vehicles sold for principal use in designated high altitude areas. (See attached list of designated high altitude areas). These vehicles must conform to high altitude emissions requirements.
In addition, there are regulations which require manufacturers to provide recommended in-use adjustments to improve performance, when applicable, for vehicles that change principal use after sale from either low to high, or high to low, altitude.
This bulletin is intended as a guide for determining which vehicles may be legally sold for principal use at high altitude, which vehicles can and must be modified prior to sale if sold for principal use at high altitude, and which vehicles may be modified after sale for improved performance when principal use is changed from high to low, or low to high, altitude.
It is critical that vehicles be delivered to the customer with the proper emission system configuration to ensure compliance with applicable emissions regulations and to provide maximum customer satisfaction. Chevrolet offers two (2) Federal altitude emission packages as the following RPO'S:
NA5 = Designed for all altitude use when NA6 is not available or low altitude only when NA6 is available.
NA6 = Designed for high altitude use.
Some Chevrolet vehicles may be converted from one of these certified configurations to another using this bulletin as a guide. Gasoline engine configurations not shown on the attached list are not modifiable.
VEHICLE EMISSION CONTROL INFORMATION UPDATE LABELS
One of the labels identified by part number below must be affixed to the vehicle whenever a vehicle is adjusted and/or modified using this bulletin.
The label should be affixed in a readily visible position in the engine compartment and where possible beside the existing Emission Control Information (Tune-Up) Label and should not be affixed to any equipment that can be easily detached from the vehicle.
Prior to installation of this label the dealer code number and date of modification must be typed (with or without ribbon) or lettered with ball point pen in the space provided.
PART NUMBER 14042590
Low altitude vehicle converted for operation at high altitude prior to sale.
PART NUMBER 14057201
Low altitude in-use vehicle modified for improved performance at high altitude.
PART NUMBER 14055121
High altitude vehicle modified for improved performance at low altitude. (This label applies to in-use as well as prior to sale).
PRIOR-TO-SALE ADJUSTMENTS VS. IN-USE ADJUSTMENTS
Altitude adjustments on new vehicles prior to delivery to the customer for conformance to high altitutde emissions standards are referred to in this bulletin as Prior-To-Sale Adjustments. Altitud adjustments on in-use vehicles for improved performance when there is a change of principal use from high altitude to low altitude or from low altitude to high altitude are referred to as Altitude Performance Adjustments or in-use modifications.
VEHICLE IDENTIFICATION
The "altitude status" of a particular vehicle may be verified by the Vehicle Emission Control Information (Tune-Up) Label. See Figure 1 for label interpretation.
Use the following chart to determine what modifications, if any, are necessary to sell a specific vehicle.
HANDLING OF ALTITUDE ADJUSTMENT EXPENSE
PRIOR-TO-SALE
Any required altitude adjustments on new vehicles prior to delivery to the customer for conformance to emission requirements in the area of principal use are the responsibility of the dealer.
IN-USE
Owners who move to high altitude counties - Dealers in high altitude areas should encourage owners who have moved to high altitude counties to have the Altitude Performance Adjustments performed on their vehicles as outlined in this bulletin. These adjustments/modifications are considered an owner maintenance expense.
Owners who move from high altitude counties - Dealers should advise owners moving to low altitude areas that they should have the Altitude Performance Adjustments performed on their vehicles as outlined in this bulletin. These adjustments/modifications are considered an owner maintenance expense.
FIGURE 2
CERTIFIED FOR ALL ALTITUDES - Field Modification For High or Low Car Line Engine/RPO Trans Altitude J 1.8 L46 All None required All 2.5 LR8/LQ9 " " " All 2.8 LE2/LH7/LC1 " " " G 3.8 LC3 " " " G 4.4 L39 " " " B 4.4 L39 4 spd auto " " All 5.0 LG4/LU5 All " " All 5.7 LMl/L83 " " "
LOW ALTITUDE VEHICLES WHICH MUST BE ADJUSTED PRIOR TO SALE FOR CONFORMANCE TO HIGH ALTITUDE EMISSIONS STANDARDS Field Modification Car Line Engine/RPO Trans For High Altitude Use
B 4.4 L39 A-3 Install service PROM #1225501. AFL.
B 3.8 LC3 Auto Install service PROM #1225505. ANC.
T 1.6 L17 M-5 Install service PROM #1225530. AFX.
T 1.6 L17 All Install jumper wire Except from circuit #450E at M-5 ALDL connector to pin #18 on ECM connector. (Refer to Figure 3 for details).
*The above modifications which must be made prior to sale for conformance to high altitude emissions standards are the same as the in-use modifications which are recommended for improved performance for vehicles that after sale change principal use from low altitude to high altitude.
HIGH ALTITUDE VEHICLES WHICH MAY BE ADJUSTED FOR IMPROVED LOW ALTITUDE PERFORMANCE Field Modification Car Line Engine/RPO Trans For Low Altitude Use
B 3.8 LC3 Auto Install service PROM #1225498. AOK.
B 4.4 L39 A-3 Install service PROM #1225491. SU.
T 1.6 L17 M-5 Install service PROM #1225531. RR.
T 1.6 L17 All Remove circuit #450E from pin #18 on the ECM connector.
PROM identification can be made from the last four (4) digits of the part number and the alpha code which appears on the PROM.
FIGURE 3
PROCEDURE FOR FABRICATING AND INSTALLING JUMPER WIRE
1. Attach a terminal P/N 14004610 to each end of a 3 foot length of 16 or 18 gage wire.
2. Connect to pin #18 of the ECM.
3. Route wire along and in front of the dash panel. Tape to panel.
4. Connect to ground terminal of the Assembly Line Diagnostic Link (ALDL).
COUNTIES WHICH ARE DESIGNATED HIGH-ALTITUDE AREAS
ARIZONA MONTANA UTAH
Apache Navajo Beaverhead Madison Beaver Cochise Yavapai Deer Lodge Meagher Box Elder Coconino Gallatin Park Cache Jefferson Silver Bow Carbon COLORADO Judith Basin Wheatland Daggett Powell Davis Adams Kit Carson Duschesne Alamosa Lake NEBRASKA Emery Arapahoe LaPlata Garfield Archuleta Larimer Banner Kimball Grand Boulder Las Animas Cheyenne Sioux Iron Chaffee Lincoln Juab Cheyenne Mesa NEVADA Kane Clear Creek Mineral Millard Conejos Moffat Carson City Lyon Morgan Costilla Montezuma Douglas Mineral Piute Crowley Montrose Elko Nye Rich Custer Morgan Esmeralda Pershing Salt Lake Delta Otero Eureka Storey San Juan Denver Ouray Humboldt Washoe San Pete Dolores Park Lander White Pine Sevier Douglas Pitkin Lincoln Summit Eagle Pueblo Tooele Elbert Rio Grande NEW MEXICO Unitah El Paso Routt Utah Fremont Saguache Bernalillo Mora Wasatch Garfield San Juan Catron Rio Arriba Wayne Gilpin San Miguel Colfax Roosevelt Weber Grand Summit Curry Sandoval Gunnison Teller DeBaca San Juan WYOMING Hinsdale Washington Grand Sans Miguel Huerfano Weld Guadalupe Santa Fe Albany Jackson Rio Blanco Harding Sierra Campbell Jefferson Hidalgo Socorro Carbon Lincoln Taos Converse IDAHO Los Alamos Torrance Fremont Luna Union Goshen Bannock Franklin McKinley Valencia Hot Springs Bear Lake Fremont Otero Johnson Bingham Jefferson Laramie Blaine Lemhi OREGON Lincoln Booneville Madison Natrona Butte Minidoka Harney Lake Niobrara Camas Oneida Klamath Park Caribou Power Platte Cassia Teton TEXAS Sublette Clark Valley Sweetwater Custer Jeff Davis Hudspeth Teton Parmer Vinta Washakie Weston
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
