https://stream.echo6.co/videos/watch/48044ca8-52f9-431d-b836-19f6429e2b79 Picking up right where Part 1 left off — we replaced the faulty MAF with a junkyard unit and cleared the mass airflow codes, but the hot restart issue was never truly confirmed as fixed. Part 2 opens with a fresh set of eyes on the car, this time checking critical sensor accuracy, ignition timing, relative compression, and spark plugs before anything else. Things seem promising until an unexpected MAF circuit low code keeps setting itself out of nowhere, throwing a curveball and pointing to a whole new layer of problems underneath. What follows is a deep-dive into the MAF power supply circuit. Using a two-channel setup to monitor both the MAF signal voltage and its power feed simultaneously, the fault gets caught live. Be sure to stick around for the breakdown at the end, where we dive even deeper into some key diagnostic takeaways from this job that are worth understanding no matter what you're working on! 🔧 Looking for Deeper Training? Whether you're a DIYer, an aspiring tech, or a working technician, ScannerDanner Premium gives you in-depth diagnostic training built around real testing and real troubleshooting: 👉 Join Here – 14 Days for $1 https://www.scannerdanner.com/join-scannerdanner-premium.html On ScannerDanner Premium, you'll get: *In-depth classroom lectures based on the material in my book *Case studies with real vehicles brought into class *Troubleshooting using proven diagnostic methods *Access to our private forum *Fundamental training in automotive electrical, electronics, and drivability diagnostics 📘 Want to Learn More About Diagnostics? Check out my field manual, Engine Performance Diagnostics, available as both an eBook and paperback at: 👉 https://linktr.ee/scannerdanner ScannerDanner Tools: https://linktr.ee/scannerdanner ⚠️ Disclaimer: ScannerDanner LLC is not responsible for misuse, unauthorized changes, or incorrect application of any information provided. Always follow proper safety protocols when using tools, equipment, or procedures discussed in this video. Use this content at your own risk. 00:00 - Picking Up the Firebird Diagnosis 00:59 - Checking Coolant & Air Temp Sensor Accuracy 02:23 - Fuel Pump Voltage Code & Startup Concerns 03:05 - Clear Flood Crank / Listening for Compression Issues 03:47 - Spark Plugs Are NOT the Answer 04:04 - Relative Compression Test 06:15 - MAF Low Code Returns After Clearing Codes 08:57 - MAF Signal Drops to Zero Volts 10:04 - Checking MAF Signal Circuit Design 12:19 - Proving This Is NOT Just a MAF Sensor Problem 13:52 - Wiring Diagram Review: MAF & Fuel Pump Relay Circuits 15:27 - Piercing Probe Testing at the Fuel Pump Relay 18:25 - Oil Pressure Switch Backup Circuit Explained 20:00 - Fuel Pump Relay Problem, But Not the Whole Problem 21:21 - Suspecting the MAF Relay 23:00 - Checking MAF Relay Ground & Power Feed 23:52 - Confirmed: Bad MAF Relay and Bad Fuel Pump Relay 25:37 - Melted Fuel Pump Relay Found 26:25 - New MAF Relay Installed / Fuel Pump Relay Removed 28:05 - MAF Signal Behavior After Relay Swap 29:17 - Why the Car Runs Without a Fuel Pump Relay 31:25 - Hot Soak Test Without Fuel Pump Relay 32:17 - Hot Restart Test: Much Better 36:53 - Final Hot Restart Before New Fuel Pump Relay 37:39 - Cold Crank Without Fuel Pump Relay 43:52 - Hot Soak Test After Repair 44:40 - Final Thoughts: Wiring Diagram Was Everything 45:21 - Cold Start With Everything Fixed 45:42 - Before vs After Fuel Pump Relay Comparison 46:07 - Final Hot Restart / Customer Can Pick It Up 46:40 - Bonus Addendum / Missed Detail Wed, 10 Jun 2026 08:35:11 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://stream.echo6.co https://stream.echo6.co/client/assets/images/icons/icon-512x512.png https://stream.echo6.co/videos/watch/48044ca8-52f9-431d-b836-19f6429e2b79 All rights reserved, unless otherwise specified in the terms specified at https://stream.echo6.co/about and potential licenses granted by each content's rightholder.