CAMPAIGN:DIESEL FUEL FILTER SENSOR-NEG.VOLT. TRANSIENTS

General Motors has determined that some 1984 Chevrolet CK10-30 Series Light Duty Model Trucks equipped with 6.2L diesel engines (RPO LH6 and LL4) may have a condition which can cause grounding of the Stanadyne fuel filter water-in-fuel (WIF) sensor.

This grounding can damage the WIF sensor module and other electrical components. The condition is caused by negative voltage transients, during engine shut off, damaging an unprotected semi-conductor in the WIF sensor module.

An inoperative WIF sensor can allow excessive amounts of water in the fuel to go undetected resulting in extensive damage to the fuel injection pump.

To prevent the possibility of this condition occurring, it will be necessary to replace the WIF sensor harness assembly.

VEHICLES INVOLVED

Involved are certain 1984 Chevrolet CK10-30 Series Light Duty Model Trucks equipped with 6.2L diesel engines (RPO LH6 and LL4). The following is a list of the vehicles involved.

VIN VIN

2GCEC14CXE1100996 2GCDC14CXE1101206 2GCGK24J1E1101051 2GCDC14C8E1101222 2GCDC14C8E1101057 2GCDC14C9E1101231 2GCFC24C6E1101069 2GCEC14C3E1101262 2GCGK24JXE1101078 2GCEK14C1E1101330 2GCDC14C2E1101085 2GCEC14C2E1101351 2GCGC24J5E1101096 2GCEC14C6E1101367 2GCGC24JOE1101118 2GCDC14C7E1101390 2GCDC14C8E1101138 2GCDC14C3E1101404 2GCDC14C7E1101146 2GCDC14C9E1101410

2GCEC14C6E1101420 2GCGC24JOE1102074 2GCGK24J6E1101434 2GCGK24JOE1102126 2GCGC24J4E1101445 2GCFC24COE1102198 2GCEC14C8E1101452 2GCGK24JXE1102229 2GCDC14C1E1101479 2GCDC14C3E1102262 2GCDC14COE1101487 2GCGC24J7E1102279 2GDCD14C4E1101508 2GCGC24J8E1102288 2GCDC14C8E1101530 2GCGK24J7E1102317 2GCDC14COE1101540 2GCGC24J9E1102350 2GCDC14COE1101554 2GCEK24C8E1102447 2GCEC14C7E1101605 2GCGC24J3E1110718 2GCDC14C6E1101610 2GCEK14C4E1110734 2GCEC14C7E1101636 2GCGK24JOE1110744 2GCEC14C3E1101665 2GCFC24C6E1110760 2GCEC14C7E1101670 2GCGC24J2E1110791 2GCDC14C5E1101677 2GCEK14C7E1110808 2GCDC14COE1101683 2GCFC24C7E1110833 2GCDC14C4E1101699 2GCGC24J9E1110853 2GCDC14ClE1101708 2GBGC24J2E1110911 2GCDC14C6E1101719 2GCEK14C3E1110949 2GCEC14C3E1101729 2GCGC24JlE1110958 2GCEC14C8E1101757 2GCFC24C8E1110985 2GCGC24J5E1101762 2GCGC24J2E1111066 2GCFC24C8E1101820 2GCGK24J9E1111083 2GCEC14C3E1101827 2GCGC24J7E1111225 2GCGC24J2E1101847 2GCEC14C5E1111243 2GCEC14COE1101882 2GCGK24JXE1111304 2GCFC24COE1101892 2GCGK24J3E1111323 2GBGC24JXE1101955 2GCGC24J4E1102059

Vehicles will also be identified by Vehicle Identification Number Computer Listings and are furnished to the involved dealers with the Campaign Bulletin. Any dealer not receiving a computer listing with the Campaign Bulletin was not shipped any involved vehicles.

OWNER NOTIFICATION

Since all vehicles are still in dealer stock, no owners are involved and therefore no owner letter is attached.

DEALER CAMPAIGN RESPONSIBILITY

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.

SERVICE PROCEDURE

1. Open hood.

2. Disconnect negative battery cables.

3. Locate fuel filter assembly on front of cowl. (See Figure 1) WIF sensor is located at bottom rear of filter and has a four wire harness to it.

4. Disconnect fuel heater harness connection at top of filter (See Figure 2).

5. Remove three screws (3/8 X 16 X 1 1/8) attaching filter to cowl while supporting filter.

6. Move filter away from cowl and hold so that rear of filter is facing up.

7. Disconnect engine wiring harness to WIF sensor harness connection and disconnect WIF sensor harness from filter body.

8. Unsnap filter canister (loosen 2 clips) but do not remove canister.

9. Remove two screws (8 X 32) holding WIF sensor.

10. Remove WIF sensor and install revised WIF sensor with diode in wiring harness.

11. Assemble and tighten two WIF sensor retaining screws to 113-170 N-cm (10-15 lb-in).

12. Reassemble canister retaining clips.

13. Reconnect WIF sensor harness to filter body and to engine wiring harness.

14. Raise filter assembly back to cowl, replace three attaching screws and tighten to 27-40 N-m (20-29 lb.ft).

15. Connect fuel heater harness to engine harness.

16. Reconnect battery cables.

17. Start engine and check for fuel leaks.

18. Install Campaign Label.

19. Close hood.

PARTS INFORMATION

Parts required to complete this campaign are to be obtained from your Chevrolet Zone Service Department.

Part Number Quantity Description ----------- -------- ----------- NPN 1 Water Sensor

CLAIM INFORMATION

Submit a Product Campaign Claim with the information indicated below:

Parts Failed **Parts Failure Labor Labor *Other Count Part No. Allowance Code Operation Hours Hours ----- --------- --------- ----- ---------- ----- ------ 1 8405 1.80 00 V1810 .5 .1

Description: Replace WIF sensor according to the instructions outlined in this campaign bulletin.

*Campaign Administrative Allowance

Dealers will automatically receive the correct labor and material allowance based on the labor operation performed.

The $1.80 identified in the "Parts Allowance Column" represents 30% of dealer net when parts are furnished at no charge by Chevrolet.

Refer to the Chevrolet Claims Processing Manual for details on Product Campaign Claim submission.

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 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.

ADMINISTRATIVE PROCEDURE

REFER TO THE CURRENT CHEVROLET SERVICE POLICIES AND PROCEDURES MANUAL AND CLAIMS PROCESSING MANUAL FOR CAMPAIGN HANDLING AND ADMINISTRATIVE PROCEDURES.

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.