Fleetwood V8-368 6.0L VIN 9 FI (1982)
Spark Plug Wire: All Technical Service Bulletins
Secondary Ignition Wire - Service Precautions
Bulletin No. T
87-102
File in Group
6D
Number
33
Corp. Ref. No.
716404R
Date
May '87
SUBJECT:
ENGINE MISS, HESITATION OR ROUGHNESS DUE TO PIERCED SECONDARY IGNITION COMPONENTS
MODELS AFFECTED: ALL CADILLAC MODELS WITH GASOLINE ENGINES
During the diagnosis procedures for an engine miss, hesitation or roughness condition, a spark plug or spark plug wire condition may be suspected.
Several types of commercial or homemade diagnostic equipment require the secondary ignition boots or wire to be pierced. This is normally done to
check for spark plug firing or to perform a cylinder balance test. Similarly, the use of pliers or other such tools to disengage a spark plug boot may pierce
or damage the boot or wire. Secondary ignition components should not be pierced for any reason.
Piercing a spark plug wire and/or distributor boot may create a failure condition that will not be immediately apparent. Over time, the hole in the pierced
boot may allow a ground path to develop creating a plug misfire condition. Heavily moisture laden air in the vicinity of the pierced boot may accelerate
this effect.
Piercing a secondary ignition wire creates a gap in the wire's conductive core. This gap is a point of high resistance. The current flow in the wire will
increase to compensate for the higher wire resistance. Over time, the wire may fail creating a plug misfire condition. The time required for the condition
to appear depends upon the extent of damage to the conductive core.
To help prevent future customer complaints that are spark plug wire related, do not pierce or otherwise damage any secondary ignition component. Only
use diagnostic equipment containing an inductive pick-up to check for spark plug firing or to perform cylinder balance tests. When disengaging a spark
plug boot from the spark plug, twist the flanged boot 1/2 turn then pull on the boot only to remove the wire.
