1988 Firebird Long Crank Diagnosis — 3 Separate Problems Found (Part 2 of 2)

The first MAF problem was gone — see Part 1 here: https://youtu.be/aSB1ygMH4KU,
but the hot restart complaint still needed to be proven. In Part 2, a new MAF circuit low code shows up and sends us into the wiring diagram.

Using scan data, scope testing, relay circuit checks, and voltage measurements, we find more than one problem hiding in the same system — including a MAF relay issue and a fuel pump relay problem affecting pump prime and MAF power supply.

Old car, same diagnostic process: prove the fault, follow the circuit, and recheck the repair.

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00:00 - Picking Up the Firebird Diagnosis
00:59 - Verifying ECT Accuracy on a Cold Engine
03:05 - Clear Flood Crank & Relative Compression Testing
06:15 - MAF Low Code Returns
08:57 - Capturing the MAF Signal Failure
10:04 - MAF Signal Circuit Analysis
12:19 - Proving the MAF Sensor Is Not the Problem
13:52 - MAF Relay & Fuel Pump Relay Circuit Review
15:27 - Fuel Pump Relay Circuit Testing
18:25 - Oil Pressure Switch Backup Fuel Pump Circuit
20:00 - Fuel Pump Relay Failure Confirmed
21:21 - Tracking Down the MAF Relay Fault
23:52 - Bad MAF Relay and Bad Fuel Pump Relay
25:37 - Melted Fuel Pump Relay Terminals
26:25 - Replacing the MAF Relay
29:17 - Why the Engine Runs Without a Fuel Pump Relay
32:17 - Hot Restart Test Results
37:39 - New Fuel Pump Relay Installed
41:09 - No Codes Present
43:52 - Hot Soak Restart After Repairs
45:21 - Cold Start Verification
45:42 - Before vs After Fuel Pump Relay Comparison
46:07 - Final Hot Restart Verification
46:40 - Why the Original MAF Caused Long Crank Times
50:29 - Explaining the MAF Signal Drop to Zero Volts
55:12 - Seeing Two Relay Failures in One Capture

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