Thanks to our Partner, NAPA Autotech

NAPA Autotech’s team of ASE Master Certified Instructors are conducting over 1,200 classes covering 28 automotive topics. To see a selection, go to napaautotech.com for more details.

Contact Information

• Email Matt: mattfanslowpodcast@gmail.com
• Diagnosing the Aftermarket A - Z YouTube Channel

Introduction:

• Fuel trims are a common topic in professional forums, classes, and diagnostics, often leading to bold diagnostic decisions.
• Matt shares his experience of quickly diagnosing vehicle issues using fuel trims, even before leaving the parking lot.

Key Challenges in Discussing Fuel Trims:

• The more you learn about fuel trims, the more nuanced and complex the topic becomes.
• It’s difficult to generalize fuel trim behavior across all vehicles, as each system has unique characteristics.
• Fuel trims are just one piece of data that must be factored into a broader diagnostic process.

What Are Fuel Trims?

• Definition: Fuel trims are adjustments made to the base fuel schedule by the engine control unit (ECU).
• Matt credits Matt Ragsdale on iATN for one of the best explanations he’s seen.

Two Primary Fuel Systems:

1. Speed Density Systems:

• Relies on the Manifold Absolute Pressure (MAP) sensor and engine RPM as primary inputs.
• Engine control algorithms tend to be more complex.

1. Mass Airflow (MAF) Systems:

• Uses the Mass Airflow Sensor (MAF) and crank sensor (RPM) as primary inputs.
• Simpler in design compared to speed density systems.
• Modern systems often blend elements of both speed density and MAF systems.

Closing Thoughts:

• Matt emphasizes the importance of understanding the nuances of fuel trims and how they vary across different vehicle systems.
• He plans to dive deeper into the topic in future episodes, providing more detailed insights and practical examples.

The Aftermarket Radio Network: https://aftermarketradionetwork.com/

Remarkable Results Radio Podcast with Carm Capriotto: Advancing the Aftermarket by Facilitating Wisdom Through Story Telling and Open Discussion. https://remarkableresults.biz/

Diagnosing the Aftermarket A to Z with Matt Fanslow: From Diagnostics to Metallica and Mental Health, Matt Fanslow is Lifting the Hood on Life. https://mattfanslow.captivate.fm/

Business by the Numbers with Hunt Demarest: Understand the Numbers of Your Business with CPA Hunt Demarest. https://huntdemarest.captivate.fm/

The...