CAMPAIGN: INJECTOR PUMP TIMING INCORRECT ADVANCED TIMING

MODELS: 1982 C,K,P LIGHT DUTY TRUCKS EQUIPPED WITH 6.2L DIESEL ENGINE

General Motors has determined that certain 1982 C, K and P25-35 Series Light Duty Trucks equipped with RPO LL4 (6.2L diesel engine), NB2 (California Emissions) and a GVW rating of 8,600 through 10,000 lbs. sold for use in the State of California may have incorrect injection pump timing. This over advanced timing may result in failure to comply with the California heavy duty emission standards.

To bring these vehicles into compliance with applicable California emission requirements, GMC Truck Dealers will retime the injection pump in accordance with the instructions outlined in this bulletin.

VEHICLES INVOLVED

Involved are certain 1982 C, K and P25-35 Series Light Duty Trucks equipped with RPO LL4 (6.2L diesel engine) and sold for use in the State of California within the following vehicle break-points:

Plant From Through ----- ---- ------- Flint Line #1 CF701766 CF706879 Flint Line #2 CF501469 CF513248 St. Louis CS504741 CS512300 Pontiac CV556777 CV576459 Fremont CZ500155 CZ501114

The specific vehicles involved in this campaign have been identified by Vehicle Identification Number Computer Listings. These listings are furnished to all involved dealers with the campaign bulletin.

DEALER CAMPAIGN RESPONSIBILITY

Dealers are to service all vehicles subject to this campaign regardless of mileage, age of vehicle, or ownership from this time forward.

Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or it is in your dealership for service in the future, you should take the steps necessary to be sure the campaign correction has been made before reselling or releasing the vehicle.

Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer, and arrangements made to make the required modification according to instructions contained in this bulletin.

If no owner's name and address were available to GMC Truck at the time of campaign initiation, the dealer will determine the owner's name and address from the dealership sales records. Please provide this information directly on the second copy of the listing next to the applicable VIN, so that our records may be updated and the appropriate notification mailed to the owner. This second copy should then be submitted to the address listed below in the previously supplied yellow campaign envelopes.

GMC Truck General Motors Corporation 101 Union Street Plymouth, Michigan 48170

OWNER NOTIFICATION

Owners will be notified of this campaign on their vehicles by GMC Truck (see copy of Owner Letter included with this bulletin). A listing of owner names and addresses has been furnished to the involved dealers to enable dealers to follow up with owners involved in this campaign. This listing may contain owner names and addresses obtained from state motor vehicle registration records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to this campaign.

SERVICE PROCEDURE

A. 1. Verify that the vehicle is 8,600 through 10,000 lb. GVWR.

2. Verify the build date of the engine. This date is stamped on the left side of the engine block on a boss just behind the water crossover. A typical stamp will be - TXD 11 13. (TXD is the engine suffix, 1 is November and 13 the day). The stamped build date must be prior to 02 18.

B. 1. Observe the injection pump timing mark area. The injection pump/front housing cover flanges should have a yellow alignment tape attached with the two lines lined up.

2. Remove the yellow tape.

3. Observe the stamped marks under the tape. The marks stamped into the pump and front housing should be offset 4mm. Consider the mark in the front housing as the zero point. The pump timing mark was set 4mm toward the left side (driver's side) from the zero point. (This is the advance direction).

4. Loosen the three pump attaching nuts.

5. Rotate the pump in the retard direction 1-1/2mm so that the timing marks will be offset by 2-1/2mm or.098 inches.

6. Retighten the three pump attaching nuts to a torque of 25-37 lb. ft.

7. Reinspect the timing marks. The mark on the pump should be 2-1/2mm (.098 inch) in the advance direction from the mark in the front housing.

8. Inscribe a mark onto the pump flange in line with the zero point mark in the front housing.

9. Put a dab of paint over the old mark on the pump.

10. The pump and housing marks should now show only two marks which are lined up.

11. DO NOT MAKE TIMING ADJUSTMENT WITH THE ENGINE RUNNING. DO NOT START ENGINE UNTIL PUMP ATTACHING NUTS ARE TORQUED SECURELY.

WARRANTY INFORMATION

Dealers should submit an accurately filled out Warranty Repair Order on each vehicle completed under this campaign.

Labor *Time Operation Allow- Trouble Number Description ance Code ------ ----------- ---- ----- V1880 Inspect engine .2 HR 96 number according to step (1) of the service procedure. If engine number is not within the engine parameters, no further action required.

V1881 Inspect engine .4 HR 96 number according to step (1) of the service procedure. If engine number is within the engine parameters, adjust timing as outlined in the service procedure of this bulletin.

For dealer to receive Administration Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.

CAMPAIGN IDENTIFICATION LABEL

Each vehicle modified in accordance with the instructions outlined in this product campaign bulletin will require a "Campaign Identification Label". Each label provides a space to include the five (5) digit Dealer Code of the dealer performing the campaign service. This information may be inserted with a typewriter or ballpoint pen.

Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner.

Apply "Campaign Identification Label" only on a clean dry surface.

ADMINSTRATIVE PROCEDURE

Procedures covering this campaign are outlined in Section V of your dealership's "GMC Truck Claims Processing Manual" issued April, 1983.

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.