This module covers diagnostic strategies for intermittent cutout and communication loss issues on older HEI distributor-equipped vehicles, as well as a CMFI-equipped 4.3L V6. Real case studies are used to illustrate how to identify root causes using a scope rather than relying on scan data.

Key topics include:

• Using EST and reference signals to pinpoint weak distributor pickup signals
• Understanding how backup spark and fuel mode can mask symptoms and what that tells you
• Interpreting a multi-channel scope capture to diagnose an injector circuit fault on a CMFI system
• Using Ohm's law and voltage drop analysis to determine not just what the fault is, but exactly where it is located in the circuit