Some 1985 FWD Deville and Fleetwood owners may experience what appears to be an incomplete fuel fill or inaccurate fuel gage reading. As published in the Owner's Manual, the nominal capacity of the fuel tank is 18.0 gallons, whereas the actual filllevels being experienced are approximately 16.6 gallons. The digital fuel gage displays "F" only when the actual fuellevel is 16.6 gallons or more. Consequently, the fuel gage may never indicate "F" or will indicate "F", but will drop to 16 gallons in a very short time.
A two-step production change is being implemented to affect fuel gage calibration and assure the usable 18.0 gallon fuel capacity. These changes are as follows:
1. A BCM PROM change, effective at B.P. 204626, was made to provide a revised fuel gage calibration. As revised, the fuel gage display will show an "F" until the fuel level drops to 15.5 gallons at which time 15 gallons will be displayed. This BCM PROM (PROM I.D. 11, Broadcast Code DDM) is available through GMWDD as service P/N 16040601.
2. Effective at B.P. 237516, a production change will be made to the fuel tank vent tube in order to allow approximately 18 gallons customer fill. There will be NO service modification to existing tanks to increase usable fuel capacity. Should a replacement gas tank be required, the revised tank with a usable capacity of approximately 18 gallons can be obtained as service P/N 22529319.
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.