Ghull
11-11-2025, 03:11 PM
Background:
Vehicle originally ran but had a rich fuel mixture issue after completing a head gasket and timing chain/guides/gears replacement. Over the course of troubleshooting that problem, the following parts and components have been replaced or tested:
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Parts Replaced / Work Done
Head gasket
Timing chains, guides, and gears
Spark plugs
Ignition coils
Fuel injectors
Fuel pump
Oxygen sensor (upstream)
Mass Air Flow (MAF) sensor
ECM (replacement unit from Flagship One)
Relay/fuse block on driver-side fender (replacement made, but no change)
Battery terminals and grounds cleaned (including G101/G102 at radiator support)
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Electrical & Diagnostic Testing
Verified 12V power and ground at OBD2 connector
Verified ~2.5V on CAN high/low lines (pins 6 and 14)
Tested resistance between MAF connector and ECM connector for continuity – good
Checked all underhood fuses and relays for power on both sides – all good
Check engine light illuminates with key ON (indicating ECM is powered)
Verified power at ignition fuses in dash and underhood fuse panels
Cleaned and re-secured multiple ground connections (battery, chassis, radiator support)
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Symptoms
Engine cranks but does not start
No fuel or spark output detected
OBD2 scanner fails to auto-detect VIN and cannot connect to ECM directly
Some other modules (like ABS/body) show partial communication
Check engine light still turns on with ignition (suggesting ECM has power but may not be communicating)
Tried both ECMs (original and replacement) — same result
Vehicle originally ran but had a rich fuel mixture issue after completing a head gasket and timing chain/guides/gears replacement. Over the course of troubleshooting that problem, the following parts and components have been replaced or tested:
---
Parts Replaced / Work Done
Head gasket
Timing chains, guides, and gears
Spark plugs
Ignition coils
Fuel injectors
Fuel pump
Oxygen sensor (upstream)
Mass Air Flow (MAF) sensor
ECM (replacement unit from Flagship One)
Relay/fuse block on driver-side fender (replacement made, but no change)
Battery terminals and grounds cleaned (including G101/G102 at radiator support)
---
Electrical & Diagnostic Testing
Verified 12V power and ground at OBD2 connector
Verified ~2.5V on CAN high/low lines (pins 6 and 14)
Tested resistance between MAF connector and ECM connector for continuity – good
Checked all underhood fuses and relays for power on both sides – all good
Check engine light illuminates with key ON (indicating ECM is powered)
Verified power at ignition fuses in dash and underhood fuse panels
Cleaned and re-secured multiple ground connections (battery, chassis, radiator support)
---
Symptoms
Engine cranks but does not start
No fuel or spark output detected
OBD2 scanner fails to auto-detect VIN and cannot connect to ECM directly
Some other modules (like ABS/body) show partial communication
Check engine light still turns on with ignition (suggesting ECM has power but may not be communicating)
Tried both ECMs (original and replacement) — same result