scope Archives - UnderhoodService
Using a Scope

Ignition coil and plug diagnostics.

Ignition Systems

The ignition coil is a very simple and robust circuit.

Ignition Diagnostics

This part of the cycle is when the mixture of air and fuel ignites and how the flame front spreads in the cylinder.

Using A Scope To Diagnose Prevents Parts Swapping

Being able to use a scope allows you to make a more accurate diagnosis faster. It is a tool that can prevent that second call to a customer advising them the initial estimate did not work. It can also be a triage tool that can save you from having to remove plugs to perform a compression test or give additional evidence if a misfire is electrical or mechanical.

Diagnosing Pulse-Width Modulated PWM Fuel Pumps

Just this summer, I experienced a situation in which the fuel pump had been replaced four different times on a single vehicle with no result because the various repair shops attempting to repair the vehicle didn’t understand how to diagnose a pulse-modulated fuel delivery system. Here are five things you should know about diagnosing them.

pwm fuel pump featured