If you're currently staring at a mess of spark plug wires, knowing the 3000gt firing order is the only thing standing between a smooth-running V6 and a car that sounds like a tractor. It's one of those things that seems simple until you're leaning over the engine bay, losing light, and trying to remember which wire goes where. Whether you're driving the base model, the SL, or the legendary VR-4, getting the ignition sequence correct is non-negotiable for the 6G72 engine.
The Mitsubishi 3000GT (and its sibling, the Dodge Stealth) is a masterpiece of 90s over-engineering. But that complexity means the engine bay is incredibly tight. When you're swapping out old wires or replacing a faulty coil pack, it's remarkably easy to mix things up. Let's break down exactly how this engine is laid out so you can get back on the road without the dreaded misfire.
Understanding the 6G72 Cylinder Layout
Before we even talk about the firing order itself, we have to talk about how Mitsubishi numbered the cylinders. If you get the numbering wrong, the 3000gt firing order won't do you much good. Since the 3000GT uses a transverse-mounted V6, the engine sits "sideways" in the bay.
The engine is divided into two banks. The rear bank (Bank 1) is the one tucked up against the firewall. This is the one everyone hates working on because there's about two inches of clearance between the intake plenum and the car's body. The cylinders back there are numbered 1, 3, and 5, starting from the passenger side (the timing belt side) and moving toward the driver's side.
The front bank (Bank 2) is the one right behind the radiator. This is much easier to access. These cylinders are numbered 2, 4, and 6, again starting from the passenger side and moving toward the driver's side. So, if you're standing at the front bumper looking at the engine, the layout looks like this:
- Rear (Firewall): 1 - 3 - 5
- Front (Radiator): 2 - 4 - 6
The Sequence: 1-2-3-4-5-6
The actual 3000gt firing order is surprisingly straightforward: 1-2-3-4-5-6. It's almost too simple to believe, given how complicated the rest of the car is. The engine alternates between the rear bank and the front bank. It starts at cylinder 1 (rear passenger side), moves to cylinder 2 (front passenger side), then back to 3, over to 4, and so on.
While the sequence is easy to remember, the physical connection at the ignition source is where most people trip up. Depending on the year of your 3000GT, you're either dealing with a distributor or a "waste spark" coil pack system.
Early Models: The Distributor Setup
If you have an early 90s base model or SL with the SOHC (Single Over Head Cam) engine, you likely have a traditional distributor. On these cars, the wires run from the distributor cap directly to the plugs. If you've pulled all the wires off at once without labeling them, you're probably having a bad day.
You'll need to find the "Number 1" mark on the distributor cap. From there, the rotor spins, sending spark to each wire in that 1-2-3-4-5-6 sequence. If you're off by even one position, the car might start, but it'll shake, pop, and generally protest.
DOHC and VR-4: The Coil Pack System
Most 3000GT enthusiasts are working with the DOHC (Double Over Head Cam) engines, specifically the Twin Turbo VR-4. These cars use a DIS (Direct Ignition System) with three coil packs. This is a "waste spark" system, meaning one coil fires two cylinders at the same time—one on the compression stroke and one on the exhaust stroke.
On these models, the coil packs are usually mounted on the driver's side of the engine. They are paired up. Usually, you'll see the coils labeled, but after thirty years of heat cycles and engine grime, those markings might be long gone.
The typical pairing on these coils is: * Cylinders 1 and 4 * Cylinders 2 and 5 * Cylinders 3 and 6
Even though the 3000gt firing order remains 1-2-3-4-5-6, the way the spark is distributed through these pairs is what keeps the engine balanced. If you accidentally swap the wires between cylinder 2 and cylinder 4, the timing will be completely thrown off, and you'll get a nasty backfire through the intake.
Why Getting it Right Matters
It's not just about getting the car to start. A wrong firing order can actually cause mechanical damage if you're persistent (or unlucky) enough. When a spark plug fires at the wrong time, it's hitting a piston that isn't in the right position. This can cause "pre-ignition" or "detonation," which puts massive stress on the connecting rods and bearings.
On a turbocharged car like the VR-4, this is even more critical. These engines are already dealing with high cylinder pressures. Adding a mistimed spark to the mix is a recipe for a blown head gasket or a melted piston. If the car feels like it's "stumbling" or "chugging" after you've done a tune-up, shut it down immediately and double-check those wire locations.
Tips for a Painless Spark Plug Wire Swap
If you're about to dive into the engine bay to change your wires, here are a few "pro tips" from someone who has spent way too many hours hunched over a 6G72.
1. The One-at-a-Time Rule The easiest way to never worry about the 3000gt firing order is to never have more than one wire off the car at a time. Pull one old wire, match it for length with a new one, and snap the new one in. It takes longer, but it's foolproof.
2. Label Everything If you must remove all the wires—maybe you're taking the intake plenum off to reach those rear plugs—get some masking tape and a sharpie. Label the wire AND the corresponding post on the coil pack. Don't trust your memory. By the time you've wrestled that plenum back on, you will have forgotten which "long wire" went to cylinder 1.
3. Check the Boot Seating The 3000GT has very deep spark plug wells, especially on the DOHC heads. Sometimes you think the wire is on, but it hasn't actually clicked onto the top of the plug. You'll hear and feel a distinct "click" when it's seated. If it's loose, the spark will jump the gap inside the boot, causing a weak spark and eventually burning out the wire.
4. Dielectric Grease is Your Friend A little bit of dielectric grease inside the spark plug boot makes it much easier to remove the wires next time. It also helps seal out moisture. Just don't glob it onto the metal contact itself; you just want it on the rubber.
Troubleshooting Misfires
So, you've checked the 3000gt firing order three times, you're sure the wires are in the right spot, but the car is still running like garbage. What gives?
On these cars, the PTU (Power Transistor Unit) is a common failure point. The PTU is a small black box that tells the coils when to fire. When it starts to go bad, it usually drops "half" of a coil, meaning you lose two cylinders at once. If your car feels like it's running on four cylinders, the PTU is a prime suspect.
Also, don't overlook the condition of the plugs themselves. Because the rear bank is such a pain to reach, many previous owners (and even some lazy shops) would only change the front three plugs. I've seen 3000GTs where the front plugs were brand new and the rear ones were the original factory plugs from 1994. If you're going to do the job, do all six.
Closing Thoughts
The 3000GT is a rewarding car to drive, but it demands respect when it comes to maintenance. Understanding the 3000gt firing order and the cylinder layout is basically "Entry Level 101" for owning one of these platforms. It might feel a bit intimidating when you look at that crowded engine bay, but once you realize the pattern is just a simple 1 through 6, it becomes a lot more manageable.
Just remember: 1-3-5 in the back, 2-4-6 in the front. Take your time, label your wires, and your V6 will purr exactly the way Mitsubishi intended. There's nothing quite like the feeling of a freshly tuned 6G72 pulling hard through the gears—and that all starts with getting the spark to the right place at the right time.