Snyder Performance Engineering’s answer to CP4.2 failure brings tried-and-true CP3 technology to the 6.7L Power Stroke platform.
Ever since it hit the assembly line, Ford’s 6.7L Power Stroke has been equipped with a Bosch CP4.2 from the factory. Unfortunately, this twin-piston high-pressure fuel pump is notorious for not only failing but taking the injectors with it when it goes—along with contaminating the rails, fuel lines, and even the return circuit. Some have addressed the issue with filtration kits that save the injectors in the event of a CP4.2 failure, others have modified the CP4.2 in an effort to make it more reliable, and there is even a complete replacement, gear-driven high-pressure fuel pump on the market. Now it’s time for Snyder Performance Engineering’s solution: a thoroughly engineered, highly refined remedy that’s been several years in the making.
Very few high-pressure fuel pumps compare to the Bosch CP3. It’s overbuilt, extremely durable, and can be modified to easily support four-digit horsepower. It’s also familiar to the diesel industry, having been the heart of the Duramax fuel system from ’01-’10, and both the 5.9L and 6.7L Cummins (’03-’07, ’07.5-’18, and ’21-‘24). Seeing no reason to reinvent the wheel, SPE chose to base its CP4.2 solution around a serpentine belt-driven CP3 supplied by Exergy Performance—one of the most trusted names in common-rail fuel components. To make the CP3 work, SPE came up with an idler system designed to remove the CP4.2 yet continue to drive the factory vacuum pump. Here’s how they did it, why it works, and why your ’11-‘present Ford needs one.
Snyder Performance Engineering’s 6.7L Power Stroke CP3 conversion is surprisingly simple. At the same time, every piece in the kit—whether machined or outsourced—has been handcrafted or handpicked with first-class quality and long-term durability in mind. The vacuum idler and fuel manifold assembly SPE designed seamlessly replaces the CP4.2 while simultaneously retaining the OEM vacuum pump. The CP3, which is accompanied by a proper ratio pulley, is a brand-new unit from Exergy Performance. And the 8-rib, Ontork serpentine belt is Kevlar-reinforced and specifically designed for high load (and high temperature) environments. SPE’s CP3 conversion kit fits all 6.7L Power Stroke engines, with the ’11-’19 model year specific system retailing for $2,500 and the ’20-’26 kit running $2,700. The system does require a single alternator accessory drive, and the company’s 34-page installation manual details how to convert dual alternator trucks to a single unit.This well-engineered and precision machined assembly is the cornerstone piece in SPE’s conversion kit, enabling the CP4.2 to disappear from the valley. Called the vacuum idler and fuel manifold assembly, it installs into the front of the 6.7L block using the OEM studs (and OEM nuts). The vacuum idler and fuel manifold, which is equipped with a heavy-duty bearing assembly, accommodates the factory drive gear for the CP4.2 and effectively makes it possible to retain the OEM vacuum pump. As an idler assembly, the timing marks on the drive gear no longer matter.It’s clear that SPE wanted its CP3 conversion to be a 100-percent bolt-in proposition for late-model Ford owners, hence the precise port locations and mounting location of the kit’s vacuum idler and fuel manifold assembly. It’s designed to accept the factory high-pressure fuel lines, which integrate seamlessly and are reused during the installation (which serves to cut down on installation costs). We’ll note that the corresponding high-pressure fuel line bracket is retained as well. The factory low-pressure fuel lines from the CP4.2 are also reused.All OEM fuel lines are reused in SPE’s 6.7L Power Stroke CP3 Conversion, and SPE supplies the additional lines you do need to install it. The new low-pressure return and feed lines SPE includes are shown here, and they come with new O-rings (two each). They’re installed prior to connecting the lines to the back (firewall side) of the vacuum idler and fuel manifold. And although it’s not pictured here, SPE also includes the pre-bent, high-pressure hard line that’s required to span from the CP3 to the vacuum idler and fuel manifold. It connects to the passenger side of the vacuum idler and fuel manifold.Thanks to SPE’s knack for engineering products with precise fitment and its highly detailed instructions, bolting the CP3 conversion in place is more straightforward than you think. Here are a few tips that stand out. 1) At the outset of the install, treat it like a secondary (engine-mounted) fuel filter change and first bleed the fuel system. 2) You don’t have to pull the fan shroud to install the system (though the fan clutch and fan do have to come out), but it’s a good idea for those that prefer plenty of working room. 3) Because you have to remove the vacuum pump for the install, carefully inspect the gasket and replace it if necessary (you don’t want to have to do all this work over again). 4) Take note of the feed and return port locations on the CP3. Knowing which is which will make installing the low-pressure fuel lines much easier. 5) Leave the top three fan idler plate mounting bolts out when reinstalling the fan idler plate onto the engine. It will be fully secured later using the hardware supplied to mount the included CP3 bracket. 6) If you have a dual alternator truck, you will either have to modify the secondary water pump (cutting off two mounting ears) or replace it with a single alternator (OEM Ford PN: BC3Z-8501-C / PW-504).The CP3 itself is secured to the supplied CP3 mounting bracket prior to being installed, and owners of single belt, dual alternator trucks should take note that one idler pulley will be run on the CP3 mounting bracket. For 2023-newer High Output dual alternator configurations, the second, 6-rib belt removed during the install goes away, as does its tensioner, brackets, and idlers. To convert these trucks to a single belt system, an idler pulley is installed on the CP3 mounting bracket and a second is added on the furthest-right location of the factory alternator bracket. These factory dual alternator applications will require ForScan or IDS to turn off the truck’s second alternator option.One of the biggest benefits of the SPE 6.7L Power Stroke CP3 conversion kit is that no PCM tuning is required to run the CP3. The engine doesn’t even know the CP4.2 has been replaced. And by driving the CP3 via serpentine belt, the load that normally bears down on the crank gear is vastly reduced (and in fact is redistributed to the snout of the crankshaft), which eliminates the slipping that’s often caused by the CP4.2. Finally, you have the serviceability factor. As opposed to the valley-mounted, gear-driven CP4.2, the belt-driven CP3 can be swapped out in a matter of minutes as opposed to hours.Working exclusively with Exergy Performance for a number of years, it was the only name SPE had in mind to supply the CP3 pumps for its conversion kit. With an in-depth background in Bosch OE development and manufacturing, Exergy was born in 2006 and has been one of the major players in both stock replacement and high performance common-rail fuel system components ever since. Here, SPE owner Dan Snyder and Exergy’s Randy Harkema converge during the 6.7L Power Stroke CP3 conversion system’s initial unveiling at the 2025 Ultimate Callout Challenge.The SPE CP3 conversion kit comes with a stock displacement, 6.7L Cummins-intended CP3 from Exergy Performance, but should you ever need to, the CP3 can easily be replaced with any other CP3 on the market—or one with added displacement, should you ever decide to pursue higher horsepower. As an example, Exergy offers 10mm, 12mm, 14mm, and even 14mm “Alpha” versions of the CP3, CP3’s which can support anything from 700 hp to more than 1,500 hp. In other words, a single CP3 can support the horsepower needs of 99.9-percent of the 6.7L Power Stroke market. The bonus is that, modified or stock, the CP3 will last.When you are ready to grow your horsepower, simply swap out the stock pump for a stroker version that can support the larger injectors you plan to run. After all, with the right injector and turbo combination the 6.7L Power Stroke platform can easily be made to turn out four-digit horsepower. We suspect many 6.7L Ford owners will opt for a 10mm, 12mm, and even a 14mm CP3 in their pursuit of more power with no sacrifice in durability. After all, a stroker version of the revered CP3 from Exergy will be just as reliable as a factory Bosch unit.Like it’s not even there… You can barely tell here, but this 6.7L Power Stroke’s ticking timebomb has been removed in favor of a CP3 thanks to SPE’s conversion kit. Yes, the CP3 is belt-driven and yes, a serpentine belt can fail. But outside of age and inferior quality, serpentine belts rarely fail on their own—and the one spec’d for SPE’s CP3 conversion is arguably the highest quality and strongest belt on the market. In SPE’s own words: “For decades there have been PTO pumps, compressors, and extra fuel pumps driven by serpentine belts on diesel engines. The 8-rib belt [included in this kit] is easily up to the task.”
