By now it is no secret that many diesel pickups on the road today are just waiting for a fuel-related disaster to occur. The news of gloom and doom is all over the internet, so it must be true. There are reports about how the high-pressure CP4 fuel pump internals can come apart, and all the fine metal remains can make their way through the fuel system destroying a lot of parts and costing vehicle owners a lot of money.
This “floating shrapnel” destroys injectors and ruins the high-pressure rails and the fuel lines all in one shot. Repairs are very pricey, and if your truck is not under a recall or warranty, you are on your own. Luckily, there is a way to keep a disaster from occurring to your diesel’s fuel system. This is where the S&S Diesel Motorsport CP4 Disaster Prevention (fuel pump bypass) kit comes into play.
There are several bypass kits available on the market from various suppliers, but not all kits are created equal. According to Justin Norris of S&S Diesel, “we try to focus on the features of our product and not what our competition is doing differently. We tested and failed multiple CP4s to validate our Gen2.1 Disaster Prevention Kit. The first failure was on our test bench to get a debris sample for analysis. Results show that 51.43 percent of the debris volume was under 21.2 microns and 27.49 percent was under 9.86 microns. Mold and tree spores fall into the 9-micron category, so we’re not too concerned with particles under that measurement making it past the return filter. Just to be safe, we also failed a pump while in a truck and continued to tow a trailer with it. All of the visible metal was contained in the return filter and the injectors still tested like new.”
While Duramax and Cummins enthusiasts have access to CP3 conversion kits to swap out the CP4 pump, Power Stroke owners do not — yet. While I was writing this article, S&S did release a new CP4 replacement pump for 2011 through 2019 Power Stroke trucks and you can read about that by clicking here. Since a Power Stroke CP3 pump swap was not an option at the time of this writing, Ford enthusiasts like Eric Bacon of Lakeland, Florida were running on borrowed time. Like many trucks on the road, Eric’s 200,000-mile Power Stroke no longer has the benefit of a warranty. He knew he was pushing his luck and it was time to add some insurance. To help him out, we reached out to S&S Diesel to secure a Disaster Prevention Kit to help keep his Super Duty on the road.
The Carnage That Can Occur
If you’ve already experienced a CP4 fuel pump failure, you can attest to the damage it causes and the associated costs to repair the damage. In most cases, you can expect to shell out several thousand dollars to cover the repairs. In fact, we learned that Ford even has a part-numbered kit at the ready for anyone needing to make the repairs (P/N: EC3Z-9B246-A). Research has shown us that you can expect to spend $3,000 for the parts and if you need to farm out the job to a shop or, gasp, a dealership, the cost goes up exponentially.
Why The CP4 Fuel Pump Can Fail
As fuel is pushed through the CP4 pump, the internal components are supposed to be lubricated by the sulfur found in diesel fuel. Since all diesel fuel to be used on roadways is now low sulfur, the lubrication properties of the diesel are non-existent. But the absence of sulfur is only one concern, as Justin explains.
“We suspect the aggressive two-lobe cam and roller design is a contributing factor to most CP4 failures,” says Justin. “Most CP4s do not have guides to keep the bucket/roller from spinning in the bore. Newer CP4s do have guided brackets, but it only takes one tiny spec of debris to seize a roller, much like rocks and hard caster wheels. The other issue is how they fail. Since the fuel from the case feeds the plungers (CP3 case and plungers are fed independently), the CP4 will continue to run and pump contaminated fuel throughout the system until the truck shuts down. By then, the damage is already done.”
Justin adds, “this is actually a benefit if you have a disaster prevention kit because it will allow you to get home or to a shop. We made it 180-ish miles while towing half of the way when we failed a pump on our truck to test the kit. The main function of the kit is to block off the flow path to the plungers and force it to go out of the pump return and into the return filter. The plungers are then fed directly from the stage two filter.”
While not a definite way to curb pump failure, it is recommended that the use of a quality fuel additive that will help lubricate the fuel system and pump, and is highly recommended.
So, to avoid an issue, we plan to protect Eric’s truck before disaster hits, and the S&S Diesel kit is just what we need. How it works is it takes the fuel coming out of the bottom of the CP4 pump, and instead of pumping it through the system, it first routes the fuel through a filter designed to capture any metal particles created if the pump starts to fail.
The CP4 Fuel Pump Bypass Install Begins
The S&S kit is designed to be a non-intrusive inclusion into the fuel system as it utilizes factory quick-connect, push-lock connections and is entirely plug-and-play. There is no cutting of any factory hoses to connect the S&S Diesel kit. I do need to tell you that you will need to remove the upper intake plenum to access the factory filtration screen for the fuel system.
I also want to let you know that not all kits are created equal, for instance, some aftermarket kits utilize a design that will not allow the contaminated fuel to enter the engine, but they will send it back to the fuel tank. When that happens, now you have contaminated fuel being pumped from the tank back through the system until it reaches the bypass, and the cycle continues. This contaminates the entire fuel system.
A quality bypass like the S&S Diesel unit incorporates a Donaldson P550943 9-micron filter (at 99-percent efficiency) plumbed into the return line, capturing contaminants before they can be sent back to the tank. This makes cleaning up after a pump failure a much easier job.
What It Does And Does Not Do
If you are hoping for a performance advantage by installing this kit, keep moving along. The advantage of this kit is saving your engine from certain disaster. It is not designed to enhance performance.
While this is a fairly involved installation, as you do need to remove the upper plenum of the intake, it is still something someone with basic hand tools and mechanical knowledge can tackle at home. S&S Diesel recommends roughly 2-1/2 to 3 hours to complete the installation of this CP4 fuel pump bypass kit. But I recommend planning an entire afternoon because you will inevitably be learning as you go. Also, you’ll likely want to do some cleaning of the parts you take off before you reinstall them. We found a lot of carbon buildup in the intake and took the time to thoroughly clean the inner passages. Regardless of the time it takes to install the bypass kit, it is well worth the peace of mind it delivers.
While this article gives a generalized overview of the installation process, there is more to it. But, you can check out the video from Thoroughbred Diesel at the top of this article to see how it is done from start to finish.