DIESEL ENGINES NOISE COMPLIANCE

VEHICLES AFFECTED: 1989 C,K,G,R,V, AND P WITH 6.2L DIESEL ENGINES

A potential noise compliance issue has been discovered on 1989 R/N Suburans with the LLA (V.I.N. Code J) 6.2L diesel engine. It is MANDATORY that these units have the timing reset PRIOR TO VEHICLE SALE to avoid potential noncompliance to Federal, Provincial, and local noise laws. Willfull violation of these laws can result in civil and/or criminal penalties. To correct this situation, the fuel injection pump timing must be reset on all affected units either in stock, or in-transit to your location PRIOR TO SALE of the vehicle.

IMPORTANT: This procedure does not apply to vehicles that were sold and delivered prior to receipt of this bulletin or the preceding DCS message, dated November 16, 1988.

VEHICLES INVOLVED

ALL Suburbans with the LL4 6.2L Diesel engine (J in the 8th position of the VIN), must be reset.

The following VIN's represent the first engines reset by the assembly plants. Those vehicles (as well as those built after these VIN's) do not need to be reset by dealer personnel.

ASSEMBLY PLANT PRODUCT VIN Breakpoint -------------- ------- --------------- Flint Suburban/Utility KF 509934 GMC KF 123336 CHEV

Use the following procedure in resetting the injection pump timing:

For noise compliance, fuel injection pump timing on all 1989 6.2L diesels is to be reset using the static timing procedure. The static timing marks, straight lines on the pump and front housing, must be aligned. The engine must be off while the timing is being set.

Static timing procedure:

Adjust: (Reference Figure 13, Page 6C2-9 in 1989 R/V/G/P Service Manual)

Injection Timing

Loosen the three pump retaining nuts.

Align the mark on the injection pump with the mark on the front cover (straight lines).

Tighten

Tighten pump retaining nuts to 40 Nm (30 ft. lbs.)

Use Labour Operation J5965 and appropriate Labour Time when submitting a warranty claim for this procedure.

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.