This module covers how to use an oscilloscope to analyze fuel injector operation and diagnose injector-related faults. Tom walks through the three main injector driver types — saturated, peak and hold, and pulse width modulated — and how each appears on a scope, whether positively or negatively controlled.

Key topics include:

• Identifying waveform characteristics such as source voltage, ground offset, inductive kick, and pintle movement signatures
• Using cursors to accurately measure injector on-time and why this differs from scanner data
• Diagnosing shorted, stuck, and non-functioning injectors through voltage and current waveform analysis
• The value of capturing voltage and current simultaneously to distinguish between excessive resistance and excessive current as causes of high voltage drop
• Strategies for analyzing bank-fired injection systems, including resistance calculations for parallel injector banks and using a current probe on individual injector legs to isolate mechanical faults