ENGINE MISSES/SURGES/BACKFIRES (POOR GROUND AT DIS MODULE). Saturn Saturn 1991

For 1990-2009 cars

# ENGINE MISSES/SURGES/BACKFIRES (POOR GROUND AT DIS MODULE)

#### SUBJECT: Engine Misses, Surges or Backfires (Poor Ground at Electronic Distributorless Ignition (DIS) Module) All 1991 Saturns - VIN No. 104754 and Below

Due to an error in the part number for the Module Asm - Elek Ign, this bulletin supercedes Bulletin No. 91-T-22, which should be discarded.

CONDITION: Engine misses, surges or backfires during all driving conditions.

CAUSE: The electronic distributorless ignition system (DIS) module bolt heads may not be making good contact with the ground straps molded into the coil housing. This may cause micro-arcing between the bolt head and the ground straps molded into the coil housing, causing interference with DIS module operation.

CORRECTIVE ACTION: Replace DIS module with a new service replacement module. The new replacement module has an internal change to the electronic grounding that protects it from any external micro-arcing that may interfere with the firing signal.

#### PROCEDURES:

1. Verify the condition. If condition is verified, perform a visual inspection making sure that the spark plug wires are seated properly and that the spark plug wires and the DIS wiring is routed correctly.

2. Torque the four DIS module mounting bolts.

Torque: 7 N,m (61 lbs. in.)

#### IMPORTANT: The two mounting bolts, closest to the front of the engine, must be properly torqued. These are the two bolts that provide a ground path for the laminated coils.

3. a. Drive the vehicle under the same conditions that originally caused it to miss, surge or backfire. If the condition has been repaired, replace the DIS module and coils.

#### NOTE: The micro-arcing will not damage the DIS module, however, the DIS module must be replaced to prevent any future reoccurrence of the condition.

Refer to the "Distributorless Ignition (DIS) Module and Coils" removal and installation procedures in the "Ignition System" section of the "Electronic Engine Controls Service Manual."

b. If the condition is still present, the problem is not due to external ground of the module. Refer to "Ignition System Diagnostics" in the "Ignition System" section of the "Electronic Engine Controls Service Manual."

PARTS REQUIREMENTS: 21020180 Module Asm - Elek Ign 21020589 Bolt/Screw - Coil & Elek Ign Module

CLAIM INFORMATION: To receive credit for this repair, submit a claim through the Saturn Dealer System as follows:

Labor Case Operation Type Description Code Time ---- ------------------------ --------- ------- VW Verify Condition, Torque T9539 1.0 hrs Bolts, Road Test, Remove and Replace Electronic Ignition Module and Bolts

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.