Ignition-Coil Reference Numbers
These coils may replace or interchange with:
- UF646
- UF-646
- DG549
- DG-549
- BL3Z-12029-A
- BL3Z-12029-B
- BL3Z-12029-C
- BL3E-12A375-CA
- BL3E-12A375-CB
- BL3E-12A375-CC
- C1814
- E1146
- NP-6134
- 36-8234
Always compare the original connector, housing and current OE number before installation.
Correction: SP534 and SP-534 are Motorcraft spark-plug references, not ignition-coil interchange numbers. They should not appear in the coil replacement list. Apparently, someone let the spark plugs sneak into the coil meeting.
Built for Turbocharged Operation
Turbocharged engines place higher demands on their ignition systems, particularly under load when cylinder pressure rises. A coil that works acceptably at idle may begin to misfire as boost builds.
These UF646-style coils are designed for compatible EcoBoost applications and feature:
- Direct coil-on-plug construction
- Application-specific electrical connectors
- Insulated internal windings
- Heat- and vibration-resistant housings
- Bolt-on installation
- OE-style mounting geometry
For a deeper explanation, review Pro Street’s guide to bad ignition-coil symptoms.
Symptoms of Weak EcoBoost Ignition Coils
Failing coils may cause:
- Rough or unstable idle
- Difficult cold or hot starting
- Hesitation during acceleration
- Misfires under boost
- Reduced engine power
- Increased fuel consumption
- Engine shaking
- Flashing check-engine light
- P0300 random misfire
- P0301 through P0306 cylinder-specific misfires
- P0351 through P0356 ignition-circuit faults
A misfire under boost can also be caused by worn spark plugs, excessive plug gap, injector faults, wiring problems or incorrect calibration. Consult Pro Street’s engine-misfire diagnosis guide before firing the entire parts cannon.
Installation Recommendations
Install ignition coils only when the engine is cool.
- Confirm the engine is the turbocharged 3.5L EcoBoost.
- Compare the original coil and electrical connector.
- Disconnect the coil connectors carefully.
- Remove the coil-retaining bolts.
- Inspect the plug wells for oil, water or corrosion.
- Examine the spark plugs for wear, fouling and excessive gap.
- Install the replacement coils and tighten the mounting bolts properly.
- Reconnect the electrical connectors.
- Clear stored codes and verify operation.
Do not install new coils over badly worn spark plugs. Excessive plug gap increases the voltage required to fire the plug and can place unnecessary stress on the replacement coils.
Pro Street’s spark-plug selection guide explains why the correct plug design and gap matter even more on turbocharged engines.
Replace One Coil or the Complete Set?
A single confirmed coil failure can be repaired individually. Replacing the complete set may make sense when:
- The coils are original and similarly aged
- Multiple cylinders have recorded misfires
- Coil housings or boots show widespread deterioration
- The engine has high mileage
- Repeated labor would be inconvenient
- The spark plugs are also being replaced
New coils can restore ignition performance lost to worn components, but they do not automatically add horsepower or improve fuel economy beyond normal operating condition.
Warranty
The advertised coverage includes:
- One year of unlimited-mileage protection against qualifying manufacturing defects
- Four additional years of extended coverage
- Five years of total advertised coverage
Warranty terms, exclusions and claim requirements should be reviewed before purchase.
There are no reviews yet.