Subaru FA20 Firing Order and Boxer Cylinder Diagram
Subaru FA20 Firing Order and Boxer Cylinder Diagram with 1-3-2-4, physical numbering, identification cautions and routing procedure.
The FA20 Boxer-Four firing order is 1-3-2-4. In common North American installed orientation, cylinders 1 and 3 occupy the passenger/right bank front-to-rear, while 2 and 4 occupy the driver/left bank front-to-rear.
The FA20 Boxer-Four firing order is 1-3-2-4. In common North American installed orientation, cylinders 1 and 3 occupy the passenger/right bank front-to-rear, while 2 and 4 occupy the driver/left bank front-to-rear. A firing order is the sequence in which the cylinders begin their power strokes. It is not the same thing as cylinder numbering, distributor-cap clock position, or ignition-coil connector order. Confusing those references can create a no-start, violent backfire, dead cylinders, or a diagnostic trail that looks like a fuel or mechanical problem.
Use the verified order only after identifying the engine family and camshaft. Classic engines can accept camshaft swaps that change the required sequence, while modern coil-on-plug engines have no distributor cap to route. The table, bank diagram, and procedure below keep those concepts separate and show how to confirm No. 1 on compression before moving any wires.
Interactive Subaru FA20 Boxer-Four firing-order diagram
Branded downloads includedPNG and PDF exports carry the TorqueSheet logo, torquesheet.com, source-page URL, and republishing attribution request. The PDF source link is clickable.
Select each cylinder to walk through the firing order. Cylinder-bank numbering and distributor direction must match the identified engine family.
Subaru Fa20 Firing Order
| APPLICATION / ITEM | SPECIFICATION | NOTES |
|---|---|---|
| Firing order | 1-3-2-4 | Confirm exact engine |
| Physical numbering | In common North American installed orientation, cylinders 1 and 3 occupy the passenger/right bank front-to-rear, while 2 and 4 occupy the driver/left bank front-to-rear. | Orient by the timing/front end |
Do not number cylinders straight across the engine bay. FA20D/BRZ naturally aspirated and FA20F/DIT turbo systems are different diagnostic applications, so match coil connectors, ECU tests and fuel-system procedures to the exact vehicle.
Which FA20 Boxer-Four firing order applies?
Covers the mechanical cylinder order shared by Subaru FA20 naturally aspirated and turbocharged boxer-four applications; control systems and service procedures remain engine-code specific. This distinction matters because the engine can look nearly identical from above. Treat the camshaft or engine assembly as the authority when parts have been mixed. A firing order cast into an intake, copied from a generic decal, or remembered from another V8 is not enough to identify a modified engine.
The application table separates the order, cylinder banks, and ignition-system notes. Read all columns before routing. The first number in 1-3-2-4 is cylinder 1, but the physical No. 1 terminal can appear in different clock positions when a distributor has been installed on a different gear tooth.
Bank numbering and verification on the FA20 Boxer-Four
Do not number cylinders straight across the engine bay. FA20D/BRZ naturally aspirated and FA20F/DIT turbo systems are different diagnostic applications, so match coil connectors, ECU tests and fuel-system procedures to the exact vehicle.
Do not number cylinders straight across the engine bay. FA20D/BRZ naturally aspirated and FA20F/DIT turbo systems are different diagnostic applications, so match coil connectors, ECU tests and fuel-system procedures to the exact vehicle.
Subaru FA20 Boxer-Four specifications can change by model year, engine, platform, wheel, and installed component. Confirm the VIN or engine identity, part numbers, fastener condition, and the current manufacturer instructions before service.
Procedures used with this specification
These steps are the same for every vehicle in this family, so they are documented once rather than repeated on each page. The values above remain specific to this Subaru FA20 Boxer-Four.
Subaru FA20 Firing Order and Boxer Cylinder Diagram FAQs
What is the subaru fa20 firing order?+
The FA20 Boxer-Four firing order is 1-3-2-4. In common North American installed orientation, cylinders 1 and 3 occupy the passenger/right bank front-to-rear, while 2 and 4 occupy the driver/left bank front-to-rear.
Technical sources
TorqueSheet favors engine- and component-specific manufacturer instructions over unsourced universal values.
1Subaru technical specifications — boxer-four enginePrimary Subaru technical documentation listing the horizontally opposed four-cylinder firing order and engine specifications.↗