Firing orders for the engines we sell: the GM LS firing order is 1-8-7-2-6-5-4-3, the Chevy 350 small-block and the 5.7 Hemi both fire 1-8-4-3-6-5-7-2, the Ford 5.4 Triton fires 1-3-7-2-6-5-4-8, the Cummins inline-six fires 1-5-3-6-2-4 and the Subaru flat-four fires 1-3-2-4.
The firing order is the sequence in which the cylinders fire. You need it when routing spark plug wires or coil connectors, and to make sense of misfire codes. Cylinder numbering differs between manufacturers, so check which cylinder is number 1 before you start.
| Engine family | Firing order | Replacement engines |
|---|---|---|
| GM LS | 1-8-7-2-6-5-4-3 | engines |
| Chevy 350 small-block | 1-8-4-3-6-5-7-2 | engines |
| 5.7 Hemi | 1-8-4-3-6-5-7-2 | engines |
| Ford 5.4 Triton | 1-3-7-2-6-5-4-8 | engines |
| Cummins 5.9 and 6.7 | 1-5-3-6-2-4 | engines |
| Subaru EJ25 and FA | 1-3-2-4 | engines |
GM LS firing order (5.3, 6.0, LS1, LS3)
The firing order for GM Gen III and Gen IV LS-family V8s, including the 4.8, 5.3 and 6.0 Vortec truck engines and the LS1, LS2 and LS3 is 1-8-7-2-6-5-4-3. Cylinders 1, 3, 5 and 7 are on the driver’s side from front to back; 2, 4, 6 and 8 are on the passenger side.
Replacement engines: GM LS engines.
Chevy 350 small-block firing order
The firing order for the Chevy small-block V8, including the 5.7L (350) TBI truck engine and the Vortec 5700 (L31) is 1-8-4-3-6-5-7-2. Cylinders 1, 3, 5 and 7 are on the driver’s side from front to back; 2, 4, 6 and 8 are on the passenger side.
Replacement engines: Chevy 350 small-block engines.
5.7 Hemi firing order
The firing order for the Chrysler 5.7L Hemi V8 in Dodge, Ram, Chrysler and Jeep vehicles is 1-8-4-3-6-5-7-2. Cylinders 1, 3, 5 and 7 are on the driver’s side from front to back; 2, 4, 6 and 8 are on the passenger side.
Replacement engines: 5.7 Hemi engines.
Ford 5.4 Triton firing order
The firing order for the Ford 5.4L Triton modular V8 is 1-3-7-2-6-5-4-8. Ford numbers the modular V8 differently: cylinders 1 to 4 are on the passenger side from front to back, and 5 to 8 are on the driver’s side.
Replacement engines: Ford 5.4 Triton engines.
Cummins 5.9 and 6.7 firing order
The firing order for the Cummins 5.9L and 6.7L inline-six diesels in Dodge and Ram trucks is 1-5-3-6-2-4. Cylinder 1 is at the front of the engine, and the cylinders are numbered in order toward the rear.
Replacement engines: Cummins 5.9 and 6.7 engines.
Subaru EJ25 and FA firing order
The firing order for the Subaru EJ25 and FA20/FA24 flat-four boxer engines is 1-3-2-4. Check the service manual for which bank each cylinder number is on before working on the ignition.
Replacement engines: Subaru EJ25 and FA engines.
Tips before working on the ignition
- Confirm the numbering: cylinder numbering is often cast into the intake manifold or noted in the service manual.
- Coil-on-plug engines: on the LS, Hemi and 5.4 Triton each cylinder has its own coil, so the firing order matters most for diagnosing misfires.
- Distributor engines: on the Chevy 350 TBI and Vortec 5700, the plug wires follow the firing order around the distributor cap in its direction of rotation.
Firing orders are the standard published sequences for each engine design; confirm with the service information for your engine before working on it. See also: all engines · LS vs Vortec · 5.4 Triton problems · 5.7 Hemi tick.
More guides: spark plug wires · what does a crankshaft do? · 5.4 Triton firing order · 5.9 Cummins firing order.
Trouble codes: P0301 cylinder 1 misfire · P0302 cylinder 2 misfire · P0303 cylinder 3 misfire · P0304 cylinder 4 misfire · P0305 cylinder 5 misfire · P0306 cylinder 6 misfire · P0307 cylinder 7 misfire · P0308 cylinder 8 misfire · all OBD2 codes.
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