Mailbag Episode: Exhaust Gas Analyzers, Testing Catalytic Converters, and Troubleshooting ADAS [E187]

Thanks to our Partner, NAPA Autotech Training

In this episode, Matt Fanslow dives into listener-submitted questions, covering a wide range of automotive diagnostic and repair topics. From personal influences in the industry to technical advice on exhaust gas analyzers, catalytic converter testing, and ADAS calibrations, Matt shares his insights and expertise.

1. Who Do You Try to Emulate?

Matt reflects on the mentors and industry leaders who have shaped his approach to diagnostics and repair.

• TV Doctors vs. Real Mentors: While he jokes about emulating fictional doctors like Hawkeye Pierce, Gregory House, and Perry Cox, Matt credits real-world experts like John Thornton, Randy Burkholder, Jim Kemper, Matthew Ragsdale, Harvey Chan, and John Riegel for their influence.
• The Value of Deep Research: Matt highlights the importance of studying SAE documents, technical manuals, and foundational books like Internal Combustion Engine Fundamentals by John B. Heywood.
• Thought Leaders in the Industry: He also mentions Jim Wilson (ScanShare.io), Scott Manna, and others for their diagnostic methodologies and problem-solving approaches.

Takeaway: Success in automotive diagnostics comes from continuous learning, leveraging industry resources, and adopting best practices from experienced professionals.

2. Exhaust Gas Analyzers – What to Look For?

A listener asks about choosing the right exhaust gas analyzer for their shop. Matt breaks down the key features:

• PC/Android Interface: Essential for graphing gas readings (lambda, air-fuel ratio) over time.
• Portability: Needed for on-road testing to monitor performance under real driving conditions.
• Fast Sample Times: Look for analyzers with low transfer delays (under 5 seconds) for accurate real-time data.
• Cost Consideration: Expect to invest 
• 5,000–
• 5,000–7,000+ for a quality unit.

 Takeaway: A good exhaust gas analyzer should provide real-time data logging, lambda calculations, and portability for effective diagnostics.

3. Testing Catalytic Converters – Temperature vs. PCM Diagnostics

A student questions the validity of using infrared thermometers to test catalytic converters after hearing conflicting advice.

• PCM Algorithms Are Superior: Modern vehicles use complex oxygen storage calculations—far more accurate than manual temperature checks.
• Why Temperature Testing Falls Short:
• A "bad" cat might still pass a temp test.
• A "good" cat might fail due to external factors (exhaust leaks, sensor issues).
• Best Practice: Trust OBD-II diagnostics, fuel control verification, and factory procedures over manual methods.

Takeaway: Always verify fuel control, exhaust integrity, and PCM data before condemning a catalytic converter.

4. ADAS Calibrations – Troubleshooting Static Windshield Camera Issues

A technician struggles with static calibrations for windshield-mounted cameras. Matt offers troubleshooting tips:

• Check the Windshield Glass: Aftermarket glass is a common culprit for calibration failures.
• Lighting Conditions:
• Too much LED glare? Try diffusers or dimming shop lights.
• Use shipping blankets to reduce reflections on the hood/dash.
• Target Placement: Ensure the target is positioned per OEM specs—avoid background interference.
• RTFM (Read the Factory Manual): Always follow OEM procedures for target setup.

Takeaway: Calibration issues often stem from glass quality, lighting, or incorrect target alignment—double-check these factors first.

Listener Q&A Submission: Have a question for Matt? Email: [e-mail]

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