GM 3.8 V-6 VIN K Engine Firing Order

GM 3.8 V-6 VIN K firing order, firing order, spark plug gap, spark plug torque, coil pack layout

Quick Summary
The firing order on the GM 3.8 V-6 VIN K engine is 1-6-5-4-3-2, and understanding that order is critical when diagnosing misfires, replacing ignition wires, or servicing the coil packs. The GM 3800 Series II VIN K engine uses a waste-spark ignition system with three coil packs mounted over the ignition control module. Spark plug gap is typically .060-inch, while spark plug torque is generally 11 lb.-ft. on aluminum cylinder heads. The engine earned a reputation as one of GM’s most durable V-6 engines due to its simple pushrod design, strong low-end torque, and reliable ignition system.Why the GM 3.8 V-6 VIN K Engine Became Legendary

The GM 3.8 V-6 VIN K engine, its firing order and ignition layout are still searched constantly because this engine powered millions of vehicles, including:

Buick LeSabre
Pontiac Bonneville
Chevrolet Impala
Buick Park Avenue
Pontiac Grand Prix

I’ve worked on dozens of these engines over the years, and the 3800 Series II remains one of the most dependable GM powerplants ever built. It wasn’t exotic, but it was incredibly durable. Many easily exceeded 200,000 miles with basic maintenance.

The VIN K version refers to the naturally aspirated 3800 Series II engine, not the supercharged L67 variant.

GM 3.8 V-6 VIN K Engine Firing Order

The GM 3.8 V-6 VIN K engine, its firing order is:
Firing Order
1-6-5-4-3-2
The cylinder numbering is:
Front Bank (toward radiator)
2
4
6
Rear Bank (toward firewall)
1
3
5
This firing order helps balance engine vibration and works with the waste-spark ignition design used on the 3800 engine.

One mistake I frequently see is crossed plug wires after tune-ups. Even experienced DIYers sometimes confuse cylinder locations because the engine sits transversely in front-wheel-drive vehicles.

Coil Pack Layout on the GM 3800

The ignition system uses three separate coil packs mounted together above the ignition control module.

Each coil fires two cylinders simultaneously:
1 and 4
2 and 5
3 and 6

That’s because this is a waste-spark system. One spark plug fires on the compression stroke while the paired cylinder fires on the exhaust stroke.

Coil Tower Layout
Looking directly at the coil packs from the front of the vehicle:
Left Coil
Tower 1
Tower 4
Center Coil
Tower 2
Tower 5
Right Coil
Tower 3
Tower 6

Correct wire routing is extremely important. Plug wires lying parallel too closely can induce crossfire and create intermittent misfires.

Spark Plug Gap for the GM 3.8 V-6 VIN K Engine

The recommended spark plug gap for most naturally aspirated 3800 Series II engines is:

Spark Plug Gap
.060-inch
That relatively wide gap works well with the high-energy ignition system GM used on the 3800 platform.

I always recommend checking the gap even on “pre-gapped” plugs. I’ve opened too many boxes over the years and found plugs damaged during shipping.

Common spark plugs used in this engine include:

AC Delco
NGK
Autolite

Spark Plug Torque Specifications

The typical spark plug torque specification for the aluminum cylinder heads used on the 3800 Series II engine is:

Spark Plug Torque

11 lb.-ft.

Overtightening is one of the fastest ways to damage aluminum threads. I strongly recommend using a torque wrench rather than “tight enough by feel.”

A tiny amount of dielectric grease inside the plug wire boot also helps prevent future wire damage and moisture intrusion.

Common Ignition Problems on the GM 3800

Even though the engine is extremely reliable, several ignition-related failures show up repeatedly:

Common Problems
• Failing ignition control modules
• Cracked coil packs
• Burned spark plug wires
• Oil contamination from valve cover leaks
• tracking on spark plugs

Misfires under load are often caused by aged plug wires rather than the coils themselves.

Final Thoughts

The GM 3.8 V-6 VIN K engine, its firing order remains one of the most searched GM ignition layouts because so many of these engines are still on the road today. The simple pushrod design, durable bottom end, and dependable ignition system made the 3800 Series II famous for longevity.

When servicing one, always verify:

• Correct firing order
• Proper coil placement
• Accurate spark plug gap
• Proper spark plug torque

Do those basics correctly, and the 3800 will usually reward you with years of reliable service.

© 2012 Rick Muscoplat