If you've started pushing your truck past the basic "tuner and exhaust" stage, you probably realized pretty quickly that the fleece dual cp3 kit 6.7 cummins owners rely on is more of a necessity than a luxury. It's one of those parts that isn't exactly "flashy" in the way a massive turbo or a chrome exhaust tip is, but man, does it make a world of difference when you're staring at your rail pressure gauge and watching it dip. We've all been there—you bury the throttle, the truck starts to pull, and then it just flattens out. That's usually your factory CP3 crying for help because it simply can't move enough fuel to keep up with your injectors.
Why One Pump Just Isn't Enough
The 6.7 Cummins is a powerhouse, no doubt about it, but the factory fueling system has a very clear ceiling. When these trucks rolled off the assembly line, they were designed to handle stock power levels with a little bit of wiggle room for towing. Once you start adding high-performance tuning or swap in some larger injectors, that single CP3 pump is essentially being asked to do double duty. It starts to get tired.
The problem isn't just that you aren't making enough power; it's that running a single pump at its absolute limit creates heat and wear. Plus, when your rail pressure drops, your atomization goes out the window. That leads to higher EGTs (exhaust gas temperatures), more smoke, and a truck that just doesn't feel crisp. That's why people move toward a dual-pump setup. By adding a second pump, you're basically splitting the workload. Instead of one pump screaming at 100% capacity, you've got two pumps working comfortably at 50%.
The Fleece Difference
So, why go with the Fleece kit specifically? There are a few options on the market, but Fleece has a reputation for making stuff that actually fits the first time. There's nothing worse than being halfway through a Saturday install and realizing you have to go to the hardware store because a bracket is slightly off or a line is three inches too short.
The fleece dual cp3 kit 6.7 cummins setup is known for being incredibly clean. They don't just throw a bunch of universal hoses at you. The kit uses a high-quality bracket that mounts the second pump right on top of the engine, driven by a heavy-duty belt. It looks like it belongs there. Honestly, if you didn't know any better, you'd almost think it was a factory option. The way they route the high-pressure lines and the fuel distribution block is just smart. It keeps the engine bay looking tidy, which is a big plus if you actually take pride in how things look under the hood.
Rock-Solid Reliability
One of the coolest things about a dual-pump setup is the redundancy. If you're out in the middle of nowhere and one pump decided to call it quits (which is rare, but hey, it's a mechanical part), the truck will usually still run on the other one. You won't be setting any land speed records, but you won't be stranded on the side of the highway waiting for a tow truck either.
Because the load is shared, the pumps also tend to last a lot longer. You aren't stressing the internals of the pumps nearly as much. For guys who use their trucks for heavy towing or long-distance hauling, that peace of mind is worth the price of admission alone.
What's Actually in the Box?
When you crack open the kit, you're going to find a few key components. First off, there's the mounting bracket. This is the heart of the system—it's beefy, precisely machined, and designed to handle the vibration of a diesel engine without cracking. You'll also get the pulleys and the belt needed to drive the second pump.
Then you've got the plumbing. Fleece includes the high-pressure fuel lines and a distribution block. This block is where the fuel from both pumps merges before heading into the fuel rail. Everything is designed to be "plug and play" as much as possible. You'll still need to provide the second CP3 pump itself—most guys buy the kit and then source a new or remanufactured pump separately, though some places sell them as a complete package.
Do You Need a Second Pump?
You might be wondering if you can just run a "stroker" pump instead. A stroker pump is a single CP3 that has been modified to flow more fuel. They're great, don't get me wrong, but they can be expensive and they're still just a single point of failure. A dual-pump setup almost always outflows a single stroker pump. If you're aiming for anything north of 600 or 700 horsepower, duals are generally the way to go. It gives you room to grow. If you decide to go with even bigger injectors down the road, you already have the fuel volume to support them.
Installation Realities
I'm not going to sit here and tell you that installing a fleece dual cp3 kit 6.7 cummins is a ten-minute job. It's a bit of a project. You're going to be working around the front of the engine, removing the fan shroud, and messing with fuel lines. If you're comfortable with a wrench and have a decent set of tools, you can definitely handle it in a weekend.
One thing to keep in mind is that you'll need to make sure your low-pressure fuel system (the lift pump in the tank or an aftermarket one like a FASS or AirDog) is up to the task. You can't feed two high-pressure pumps with a weak supply. Most guys who install dual CP3s already have an aftermarket lift pump, but if you don't, you'll want to add that to your shopping list.
Tuning for Dual Pumps
This is a big one. You can't just bolt this kit on and expect the truck to run perfectly right away. The truck's ECM (Engine Control Module) needs to be told that there are now two pumps trying to maintain rail pressure. If you don't update your tuning, the truck might get confused and throw codes because it thinks the fuel pressure is behaving strangely.
Most of the popular tuners for the 6.7 Cummins have "dual pump" files ready to go. You just let your tuner know what you've installed, and they'll send over a map that calibrates the regulators on both pumps so they work in harmony. Once the tuning is dialed in, the throttle response is usually much crisper, and the truck feels like it has a lot more "meat" in the mid-range.
The Driving Experience
So, what's it like once it's all bolted up? The first thing you'll notice is how stable the rail pressure is. If you have a monitor like an Edge CTS3, you can watch the commanded pressure versus the actual pressure. With a single pump on a hot tune, you'll see that actual pressure start to drop off as the RPMs climb. With the Fleece dual kit, that actual pressure stays glued to the commanded pressure.
It makes the truck feel much more consistent. Whether you're merging onto the highway or pulling a heavy trailer up a grade, the power is just there. There's no hesitation, no sputtering, and none of that "dying out" feeling at the top end of a gear. It transforms the truck from something that feels like it's struggling to something that feels like it has endless lungs.
Is It Worth It?
Look, performance parts aren't cheap, and the fleece dual cp3 kit 6.7 cummins is an investment. But if you're serious about your 6.7 Cummins, it's one of the best reliability and performance mods you can do. It takes the stress off your fuel system, provides room for future power mods, and makes the truck a whole lot more fun to drive.
If you're tired of running out of fuel and you want a kit that is engineered to fit right and last for the long haul, this is probably the route you want to take. It's one of those "buy once, cry once" situations. Do it right the first time, and you won't have to worry about your fueling system again for a very long time. Just make sure you've got your tuning lined up, grab a buddy to help with the install, and get ready to actually feel what your 6.7 is capable of when it's finally getting all the fuel it wants.