Ignition - Precautions On Use of Spark Tester

Bulletin Number:
92-6-57
Reference Number:
216517
Publish Date:
8/92



Subject:
INFORMATION ON CORRECT USE OF J-26792 (ST-125)

Models
Affected:
1984-92 ALL MODELS WITH ELECTRONIC DISTRIBUTORLESS IGNITION (DIS) SYSTEMS


NOTICE:
The following conditions may cause damage to ignition system components or incorrect diagnosis and replacement of good parts due to excessive secondary voltages required to fire the ST-125:

- Failure to ground secondary wire for companion cylinder.
- Use of more than one ST-125 on a single coil.
- Failure to clip ST-125 directly to ground.

When connecting the ST-125 HEI Spark Tester (J-26792) to vehicles equipped with Electronic Distributorless Ignition (DIS) Systems, the following procedure must be used to avoid damage to ignition system components and misdiagnosis:

1. Install ST-125 at plug end of secondary wire for suspect cylinder and clip ST-125 to ground at engine block. Avoid placing ST-125 near Sensors, Modules, or other Electronic Devices which may be affected by electromagnetic interference.

2. Disconnect plug end of secondary wire for companion cylinder and jumper directly to ground at engine block.

3. Continue with appropriate diagnosis. (Chart A-3, Chart C-4, or "Symptoms" Section "6E3-B").