Coil and Ignition Housing - Characteristic Conditions
File in Section: 6E - Engine Fuel & EmissionBulletin No.: 67-65-34
Date: November, 1996
INFORMATION
Subject:
Coil and Ignition Housing Characteristic Conditions
Models:
1988-97 Buick Skylark
1988-93 Chevrolet Beretta
1995-97 Chevrolet Cavalier
1997 Chevrolet Malibu
1987-91 Oldsmobile Calais
1990-91 Oldsmobile Cutlass Supreme
1992-97 Oldsmobile Achieva
1997 Oldsmobile Cutlass
1988-97 Pontiac Grand Am
1990-91 Pontiac Grand Prix
1995-97 Pontiac Sunfire
with Quad 4 and LD9 Twin Cam Engines
(VINs A, D, 3, T - RPOs LG0, LD2, L40, LD9)
A high percentage of ignition coils and ignition coil housings from the above vehicles returned under the corporate warranty return program have been tested with no trouble found. A review of warranty repair orders has indicated that ignition coils and housings are being replaced for conditions that are characteristic of this ignition system, and not indicative of a part failure.
A large number of ignition coil housings from 1995 and 1996 Quad 4 and Twin Cam engines have, after a period of use, a characteristic marking often referred to on repair orders as "tracking". This "tracking" is a characteristic of the high voltage distribution through the coil housing and can easily be wiped away with a damp rag. These false "tracks" are most often seen on the bottom of the housing between the secondary ignition terminals. (See Figure 1) Actual "tracking" from a high voltage arc, is characterized by damage to the coil housing with black residue or carbon imbedded in housing material. This type of damage cannot be wiped away to any significant degree and can often be felt as well as seen.
There have also been numerous ignition coils replaced due to a condition often described on repair orders as a "burn" or "burned". All Quad 4 and Twin Cam ignition coils have a pair of welds on the metal portion nearest the connection for the primary wiring. These welds are made after the coil is assembled and in some cases the welding process leaves a black mark or some debris on the coil. This debris can be wiped away with a damp rag leaving behind a small black mark on the corner of the coil nearest the weld. This weld process in no way degrades the function of the coil and is a natural part of the manufacturing process. (See Figure 2)
Ignition parts should be diagnosed by using the information contained in Section 6E (Driveability and Emissions or Engine Controls) of the appropriate Service Manual, keeping these characteristic conditions in mind. Always follow the Strategy Based Diagnostic method for ignition components, using appropriate resistance values and informed visual inspection if necessary.