REDUCED PERFORMANCE/ROUGH IDLE #1 CYL. SPARK PLUG WIRE SHORT. Cadillac Limousine 1985

For 1990-2009 cars

# REDUCED PERFORMANCE/ROUGH IDLE #1 CYL. SPARK PLUG WIRE SHORT

#### MODELS AFFECTED: 1985 FRONT WHEEL DRIVE DEVILLES AND FLEETWOODS

Some 1985 Front Wheel Drive Devilles and Fleetwoods built before B.C. number 287300 may experience rough or unstable idle, rich driveability conditions or reduced engine performance during acceleration and transmission shifts. These conditions may be caused by the number one cylinder spark plug wire shorting to ground.

The number one cylinder spark plug wire on some vehicles built before B.C. number 287300 may have been misrouted behind the air hose connecting the AIR pump and the AIR system filter assembly. A chafing motion between the number one spark plug wire and the air hose retaining clip can result in a bare wire shorting against the air hose clip, the air hose, or the AIR pump (see Figure 1).

Before diagnosing a vehicle built before B.C. number 287300, follow the procedure below:

1. Inspect the number one cylinder spark plug wire. If the wire is routed as in Figure 1, proceed to Section 6E of the Front Wheel Drive "C" Service Information Manual for diagnosis.

2. If the number one spark plug wire is routed incorrectly, inspect the spark plug wire for signs of spark arcing and/or a snapping sound.

#### CAUTION:

To avoid electrical shock, do not touch the spark plug wire while the engine is running.

3. Turn the engine off.

4. If a short to ground condition was not noted in step 2, remove the spark plug wire from the number one cylinder spark plug and correctly route the wire to the outside of the air hose (see Figure 1).

#### NOTICE: Use a spark plug wire boot removal tool or carefully twist the flanged boot 1/2 turn before removing and pull only on the boot to remove the wire.

5. If a short to ground condition was noted in step 2, perform the following (refer to Figure 2):

Remove the number one cylinder spark plug wire conduit.

Loosen the number one cylinder spark plug wire from its retainers.

Remove the number one cylinder spark plug wire and replace it with spark plug wire P/N 12036955.

Reinstall the spark plug wire conduit and place the spark plug wire into its retainers. The spark plug wire conduit must be reinstalled and the wire must be correctly routed and placed in proper retainers to avoid radio ignition noise, crossfiring spark plup or shorting of the leads to ground.

For warranty purposes, use the following labor Operation Numbers:

OPERATION OPERATION NO. TIME

Reroute Number One Cylinder Spark Plug Wire T6118 .2 Replace Number One Cylinder Spark Plug Wire J4206 .3

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.