Gary Goms - Technical Contributor
Chasing Oxygen Sensor Heater Codes

Diagnosing common O2 sensor heater codes isn’t necessarily difficult, it’s just about answering how fast and how hot.

Engine Cooling Systems and Rocket Science

Internal combustion engine designs are trending smaller with higher turbocharger boosts to produce big-engine torque and horsepower ratings.

Cylinder Sealing: The Art of Measuring What’s Happening Now

Conventional cranking compression and cylinder leakage tests have become time-consuming and often inaccurate. Modern engines require a more accurate method of testing cylinder sealing.

On-board testing capabilities cut compression testing time from hours to minutes on this 2013 Ford F-150.
Starter & Battery Diagnostics

Because the permanent or “ferrite” magnets that are used in starters are made of a brittle ceramic material, they are vulnerable to cracking caused by sudden impacts. Cracked magnets can be tough to diagnose; here’s what you should be looking for.

Cracked magnets can be tough to diagnose, which is why it’s usually better to replace the starter as an assembly than to repair or rebuild it.
Understanding 5-Volt Reference Signals

Author Gary Goms provides two real-world examples of how two- and three-wire sensors can cause an intermittent rich operating condition.

Gary Goms Underhood Service article
Master Cylinder Inspections

Although modern master cylinders are reliable, they do require periodic inspection.

master cylinder inspections
Secondary Ignition Diagnostics

There’s more to ignition science than looking for the classic quarter-inch long “hot blue spark” jumping from coil secondary to ground.

spark plug, secondary ignition diagnostics
LTF and STF Fuel Trim Feedback Loops: Rich, Lean and in Between

Air/fuel ratios can range from 13:1 to 22:1, but no matter what the ratio, there’s a fuel trim cell that addresses them.

Emission Systems: How Catalytic Converters Operate

An ignition system misfire is the most common cause of catastrophic converter failure. Here’s what you need to know.

How Technology is Changing Charging System Diagnostics

Here’s what you need to know to better understand the concept of computer-controlled charging systems.

Cooling System Design

Given the advanced state of internal combustion engine (ICE) technology, some recent cooling system innovations will actually increase engine torque and fuel economy while reducing exhaust emissions. Let me simplify that idea: new cooling system technology will make ICEs run better and cleaner. So, let’s get review some basics.

Diagnosing, Servicing & Replacing Batteries

It’s all about amp/hours — how to recognize plate sulfation when we see it.