1985 Corvette: Service Bulletin: High Output Ignition Coil Replacement

Subject: High Output Ignition Coil Replacement
Model and Year: 1985 L69 Camaro and Monte Carlo, 1985 LB9 Camaro and 1985 L98 Corvette
Source: Chevrolet Service Bulletin
Bulletin Number: 85-93 - June, 1985


Some 1985 Camaro, Monte Carlo and Corvettes with high output ignition coils may exhibit driveability problems ranging from hesitations, sags, and stumbles to complete ignition cut-out.  These conditions my be caused by extended exposure to high temperatures.

Should any vehicle/engine combination stated above experience the described driveability conditions and normal service procedures (See Service Manual) do not correct the conditions, the following steps are to be taken to prevent future reoccurrence:

  1. Replace the high output coil and distributor module with standard output coil and module as listed below:
    Model YearVehicle ModelEngine RPOReplacement CoilReplacement Module
    1985 Camaro, Monte Carlo L69 1985473 1976908
    1985 Camaro LB9 1985473 1976908
    1985 Corvette L98 1985474 1976908
  2. Remove and regap spark plugs to .035 inch.
  3. Check and reset ignition timing to specifications as indicated on the vehicle emissions label.


UsageReplace With
Camaro With L69 and NA5 14086583
Camaro With L69 and NB2 14086585
Camaro With LB9 and NA5 14086587
Camaro With LB9 and NB2 14086589
Monte Carlo with L69 and NA5 14086584
Monte Carlo with L69 and NB2 14086586
Corvette with L98 and NA5 Less NN5 14086591
Corvette with L98 and NA5 With NN5 14086592
Corvette with L98 and NM8 14086593

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.

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Article ID: 578
Created: July 28, 2014
Last Updated: July 28, 2014
Author: Rob Loszewski

Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article.php?id=578