GM 6.6 Duramax Firing Order Diagram
2007.5–2010 LMM 6.6L Duramax V8 firing order 1-2-7-8-4-5-6-3, cylinder numbering, interactive diagram, connector-routing notes, troubleshooting, FAQs.
The 2007.5–2010 LMM 6.6L Duramax V8 firing order is 1-2-7-8-4-5-6-3. Passenger/right bank is 1-3-5-7 and driver/left bank is 2-4-6-8, with both banks numbered from the front of the engine toward the transmission.
The 2007.5–2010 LMM 6.6L Duramax V8 firing order is 1-2-7-8-4-5-6-3. Passenger/right bank is 1-3-5-7 and driver/left bank is 2-4-6-8, with both banks numbered from the front of the engine toward the transmission. The order is simple to print; the difficult part is applying it to the correct physical cylinders. The LMM diagnostic manual explicitly lists 1-2-7-8-4-5-6-3. This order differs from classic Chevrolet gasoline V8, LS/EcoTec3 gasoline V8 and Ford diesel sequences, even though their cylinder-bank drawings can look superficially similar.
A firing-order diagram should answer three separate questions: which cylinder is which, what sequence the crankshaft uses, and how the ignition system reaches each cylinder. Identify the RPO from the vehicle and engine before electrical work. Injector balance-rate display, harness connector position and the eight mechanical combustion events are related diagnostic references but are not interchangeable labels. The interactive drawing below keeps the order visible while the table preserves the numbering notes in crawlable text.
Before disconnecting anything, photograph the harness or leads, label both ends, and identify the engine from a durable source. That five-minute audit is faster than diagnosing a crossed pair after the engine has been reassembled.
Interactive GMC 2007.5–2010 LMM 6.6L Duramax V8 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.
Gm 6.6 Duramax Firing Order Diagram
| APPLICATION / ITEM | SPECIFICATION | NOTES |
|---|---|---|
| Firing order | 1-2-7-8-4-5-6-3 | One complete four-stroke combustion sequence |
| Cylinder numbering | Passenger/right bank is 1-3-5-7 and driver/left bank is 2-4-6-8, with both banks numbered from the front of the engine toward the transmission. | Confirm orientation before moving wires or coils |
| Diagnostic rule | Identify before swapping | Coil connector number and cylinder number are not interchangeable |
The LMM diagnostic manual explicitly lists 1-2-7-8-4-5-6-3. This order differs from classic Chevrolet gasoline V8, LS/EcoTec3 gasoline V8 and Ford diesel sequences, even though their cylinder-bank drawings can look superficially similar.
Reading the 2007.5–2010 LMM 6.6L Duramax V8 diagram correctly
Passenger/right bank is 1-3-5-7 and driver/left bank is 2-4-6-8, with both banks numbered from the front of the engine toward the transmission. Read the vehicle as installed and use the manufacturer's left/right convention, not the side from which you happen to be standing. The first cylinder listed in 1-2-7-8-4-5-6-3 begins the sequence but does not define a universal connector position.
The LMM diagnostic manual explicitly lists 1-2-7-8-4-5-6-3. This order differs from classic Chevrolet gasoline V8, LS/EcoTec3 gasoline V8 and Ford diesel sequences, even though their cylinder-bank drawings can look superficially similar. Identify the RPO from the vehicle and engine before electrical work. Injector balance-rate display, harness connector position and the eight mechanical combustion events are related diagnostic references but are not interchangeable labels. On coil-on-plug engines, use the diagram for cylinder identity and diagnosis; the PCM, not a physical distributor cap, schedules spark.
Which 2007.5–2010 LMM 6.6L Duramax V8 firing order applies?
The LMM diagnostic manual explicitly lists 1-2-7-8-4-5-6-3. This order differs from classic Chevrolet gasoline V8, LS/EcoTec3 gasoline V8 and Ford diesel sequences, even though their cylinder-bank drawings can look superficially similar. 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 1-2-7-8-4-5-6-3 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 2007.5–2010 LMM 6.6L Duramax V8
Identify the RPO from the vehicle and engine before electrical work. Injector balance-rate display, harness connector position and the eight mechanical combustion events are related diagnostic references but are not interchangeable labels.
The LMM diagnostic manual explicitly lists 1-2-7-8-4-5-6-3. This order differs from classic Chevrolet gasoline V8, LS/EcoTec3 gasoline V8 and Ford diesel sequences, even though their cylinder-bank drawings can look superficially similar.
GMC 2007.5–2010 LMM 6.6L Duramax V8 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 GMC 2007.5–2010 LMM 6.6L Duramax V8.
GM 6.6 Duramax Firing Order Diagram FAQs
What is the gm 6.6 duramax firing order diagram?+
The 2007.5–2010 LMM 6.6L Duramax V8 firing order is 1-2-7-8-4-5-6-3. Passenger/right bank is 1-3-5-7 and driver/left bank is 2-4-6-8, with both banks numbered from the front of the engine toward the transmission.
Technical sources
TorqueSheet favors engine- and component-specific manufacturer instructions over unsourced universal values.
12007.5–2010 GM 6.6L LMM Duramax diagnostic manualApplication-specific LMM diagnostic manual explicitly listing the Duramax firing order as 1-2-7-8-4-5-6-3 and tying injector diagnosis to physical cylinder identity.↗