DIESEL ALTITUDE ADJUSTMENT ADJ. TO IMPROVE PERFORMANCE

Subject: 1982 PONTIAC ALTITUDE PERFORMANCE ADJUSTMENTS - 5.7L V-8 DIESEL ENGINE

The 1982 Pontiac's equipped with 5.7L V-8 diesel engines will be manufactured with either high or low altitude diesel systems. A vehicle with a high altitude system will be invoiced with option NA6. This type of system can also be identified by the emission label attached to the fan shroud. The label will indicate that the vehicle was designed for principal use at either high or low altitude.

These adjustments are considered Altitude Performance Adjustments and apply only to in-use vehicles. They should not be used to modify vehicles prior to sale.

Dealers must not sell vehicles with low altitude systems for principal use at high altitude.

CONVERSION OF LOW ALTITUDE SYSTEM TO HIGH ALTITUDE

Dealers in high altitude areas should encourage owners who have moved to high altitude counties to purchase the service adjustment procedure outlined below, which is considered an owner maintenance expense. See map (Figure 1) and list of counties (Figure 2 shown on the reverse side) which the Environmental Protection Agency has designated as high altitude counties.

1. Replace the EGR vacuum control valve assembly (see Figure 3 on page 3) with the assembly shown in the Parts Information section of this bulletin.

2. Install magnetic tachometer probe, run engine until it is at operating temperature. Set idle speed to specifications, turn engine off.

3. Remove air cleaner and air crossover assemblies and install screen covers J-26996-2.

4. Install shop towel in the intake manifold valley area under the injection pump head to absorb any fuel leakage. Remove housing pressure tap plug and seal located on the rear of the pump (see Figure 4 on page 3).

5. Assemble locknut and new seal (0-ring) to metering valve stop screw.

6. Install assembly in injection pump until locknut contacts pump housing. Tighten locknut.

7. Place transmission in Park, turn A/C off and start engine.

8. Loosen locknut and slowly turn metering valve stop screw clockwise until idle speed drops approximately 10 rpm.

9. Turn metering valve stop screw counterclockwise 3 turns on wagons and 21/2 turns on all except wagons and tighten locknut.

10. Check installation for fuel leaks and remove shop towel from intake valley.

11. Turn engine off.

12. Remove magnetic tachometer probe and screened covers from intake manifold and reinstall parts removed.

13. Type or print with ballpoint pen the dealer code and date in the space provided on the supplemental emission control label (part number 14057201 or equivalent, see Figure 5 on page 3, part of kit). The label must be placed next to the existing underhood emission control information label to the extent possible. The label should not be affixed to any equipment that can be easily detached from the vehicle. Wash off the area with soap and water, dry thoroughly, and apply the new label.

DESIGNATED HIGH ALTITUDE COUNTIES* Requiring High Altitude Emission Control

ARIZONA Lake Butte NEVADA Sierra Tooele Apache La Plata Camas Carson City Socorro Uintah Navajo Larimer Caribou Douglas Taos Utah Las Animas Cassia Elko Torrance Wasatch COLORADO Lincoln Clark Esmeralda Union Wayne Adams Mesa Custer Eureka Valencia Weber Alamosa Mineral Franklin Humboldt Arapahoe Moffat Fremont Lander OREGON WYOMING Archulets Montezuma Jefferson Lyon Lake Albany Boulder Montrose Madison Mineral Carbon Chaffee Morgan Minidoka Storey UTAH Converse Clear Creek Ouray Oneida White Pine Beaver Fremont Conejos Park Power Box Elder Goshen Costilla Pitkin Teton NEW MEXICO Cache Hot Springs Crowley Pueblo Valley Bernalillo Carbon Johnson Custer Rio Blanco Catron Daggett Laramie Dolores Rio Grande MONTANA Colfax Davis Lincoln Delta Routt Beaverhead Curry Duchesne Natrona Denver Saguache Deer Lodge De Baca Emery Niobrara Douglas San Juan Gallatin Grant Grand Park Eagle San Miguel Jefferson Guadalupe Iron Platte Elbert Summit Madison Harding Juab Sublette El Paso Teller Meagher Lincoln Kane Sweetwater Fremont Washington Park Los Alamos Millard Teton Garfield Weld Silver Bow Luna Morgan Uinta Gilpin McKinley Puite Weston Grand IDAHO NEBRASKA Mora Rich Gunnison Bannock Banner Rio Arriba Salt Lake Hinsdale Bear Lake Kimball Sandoval San Juan Huerfano Bingham Sioux San Juan Sanpete Jackson Blaine San Miguel Sevier Jefferson Bonneville Santa Fe Summit

Counties which have substantially all of their area above 4000 ft. Ref. Federal Register, Vol. 42, No. 76, April 20, 1977, pg. 20464

Figure 2

PARTS INFORMATION

PART PART NUMBER ---------------------------- --------------------------- 1. EGR Vacuum Control Valve Assembly - High Altitude Application

All Models 22515542 or equivalent

Label 14057201 or equivalent

2. Altitude Adjustment Kit 22516487 or equivalent

KIT CONTENTS QUANTITY ---------------------------- -------- Locknut 1 Seal 1 Metering Valve Screw 1 Label (Part Number 14057201 1 Or Equivalent) - (Refer to Figure 5 below)

Suggested Time

The suggested time to perform High Altitude adjustment and part replacement procedure previously mentioned is 0.4 hour labor.

CONVERSION OF HIGH ALTITUDE VEHICLES TO LOW ALTITUDE

Dealers should advise owners moving to low altitude areas that they should purchase the service adjustment procedure outlined below which is considered an owner maintenance expense.

1. Replace the EGR vacuum control valve assembly (refer to Figure 3 shown on page 3) with the assembly shown in the Parts Information section of this bulletin.

2. Remove air cleaner.

3. Determine if the injection pump contains a pressure tap plug or a metering valve stop screw (refer to Figure 4 on page 3).

4. If equipped with a pressure tap plug go to Step 6.

5. If equipped with a metering valve stop screw, remove air crossover, loosen locknut, and turn stop screw out (counterclockwise) 4 to 5 turns. Tighten locknut and install crossover.

6. Install air cleaner.

7. Type or print will ballpoint pen the dealer code and date in the space provided on the supplemental emission control label (part number 14055121 or equivalent, see Figure 6 below). The label must be placed next to the existing underhood emission control information label to the extent possible. The label should not be affixed to any equipment that can be easily detached from the vehicle. Wash off the area with soap and water, dry thoroughly, and apply the new label.

PARTS INFORMATION

PART PART NUMBER ----------------------------- ------------------------ 1. EGR Vacuum Control Valve Assembly - Low Altitude Application All Models 22514746 or equivalent

2. Label - (Refer to Figure 6) 14055121 or equivalent

Suggested Time

The suggested time to perform the Low Altitude adjustment and part replacement procedure previously mentioned is 0.4 hour labor.

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.