Chevy Silverado 4.3 Firing Order and Cylinder Numbering
Chevy Silverado 4.3 firing order 1-6-5-4-3-2 with cylinder numbering, distributor and coil-system distinctions, interactive diagram, FAQs, and sources.
The traditional Chevrolet 4.3L V6 firing order is 1-6-5-4-3-2. Cylinders 1-3-5 are on the driver/left bank and 2-4-6 on the passenger/right bank, front to rear.
The traditional Chevrolet 4.3L V6 firing order is 1-6-5-4-3-2. Cylinders 1-3-5 are on the driver/left bank and 2-4-6 on the passenger/right 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 Chevrolet Silverado 4.3L V6 firing-order diagram
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Select each cylinder to walk through the firing order. Cylinder-bank numbering and distributor direction must match the identified engine family.
Chevy Silverado 4.3 Firing Order
| APPLICATION / ITEM | SPECIFICATION | NOTES |
|---|---|---|
| LU3 firing order | 1-6-5-4-3-2 | Chevrolet's 2004 technical package |
| Driver/left bank | 1-3-5 | Front to rear |
| Passenger/right bank | 2-4-6 | Front to rear |
| Ignition layout | Varies by generation | Distributor or coil-based |
Older 4.3L engines use a distributor, while later versions use distributorless or coil-based ignition. The mechanical order stays the same, but the routing task changes.
The documented Silverado LU3 reference
Chevrolet's 2004 Silverado technical package identifies the LU3 as a 90-degree 4.3L V6 and lists firing order 1-6-5-4-3-2. The source anchors the sequence to a named engine RPO rather than treating every engine called ‘4.3’ as identical.
Later Silverado 4.3L engines, including the EcoTec3 LV3, use different controls and ignition hardware. Confirm the RPO before applying a distributor-cap, coil, injector, or connector diagram even where the basic firing sequence agrees.
Separate the firing order from the ignition layout
A Vortec distributor cap and a later Silverado coil system can share the same 1-6-5-4-3-2 combustion sequence while looking completely different above the engine. Use the order to describe the next power event, then use the engine-specific diagram to identify the cap post, coil, or connector serving that cylinder.
On a distributor engine, establish cylinder 1 at compression top dead center and observe the rotor before calling any physical cap position No. 1. Distributor installation position can move the practical No. 1 terminal without changing the firing order.
Which Silverado 4.3L V6 firing order applies?
The 4.3L V6 is not numbered like an inline engine; odd and even cylinders occupy opposite banks. 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 1-6-5-4-3-2 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 Silverado 4.3L V6
Identify distributor versus later ignition hardware before applying a cap-routing illustration.
Older 4.3L engines use a distributor, while later versions use distributorless or coil-based ignition. The mechanical order stays the same, but the routing task changes.
Chevrolet Silverado 4.3L V6 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 Chevrolet Silverado 4.3L V6.
Chevy Silverado 4.3 Firing Order and Cylinder Numbering FAQs
What is the Chevrolet Silverado 4.3L V6 firing order?+
Chevrolet's cited LU3 technical package lists 1-6-5-4-3-2.
How are the 4.3L cylinders numbered?+
Cylinders 1-3-5 are on the driver/left bank and 2-4-6 are on the passenger/right bank, each bank numbered front to rear.
Does every Silverado 4.3 use a distributor?+
No. Older applications use a distributor while later engines use coil-based electronic ignition. Identify the engine RPO and hardware before routing anything.
Where is the No. 1 terminal on a replacement distributor?+
Place cylinder 1 at compression top dead center and use rotor position plus the engine-specific procedure; cap orientation can vary with distributor installation.
Technical sources
TorqueSheet favors engine- and component-specific manufacturer instructions over unsourced universal values.
12004 Chevrolet Silverado restoration package — 4.3L engine dataChevrolet's technical package listing the LU3 4.3L V6 as a 90-degree engine with firing order 1-6-5-4-3-2.↗2GM Owner Center manualsOfficial GM lookup for the applicable model-year owner manual.↗3GM Owner Center manuals and guidesPrimary Chevrolet and GMC year/VIN manual lookup.↗