What is the fuel pump problem with the 6.7 powerstroke?

The most widely reported fuel-system problem on Ford’s 6.7 Power Stroke diesel centers on the high-pressure fuel pump (HPFP), particularly the Bosch CP4.2 unit. When this pump fails or degrades, the engine can lose proper high-pressure fuel delivery, leading to hard starts, reduced power, stalling, or no-start conditions. In some cases, debris from a failing CP4.2 can contaminate the fuel rail and injectors, causing more extensive—and expensive—engine damage.

The 6.7 Power Stroke, introduced for Ford’s heavy-duty lineup in 2011, uses a common-rail fuel system that relies on a high-pressure pump to deliver diesel to the injectors. Over time, wear, contamination, or a faulty lift pump can compromise this system. The CP4.2 HPFP has emerged as a recurring failure point in several model years, triggering a cascade of symptoms from loss of power to potential engine damage if the fuel rails, lines, or injectors are exposed to debris. Maintenance practices—like using clean fuel, timely filter changes, and ensuring the lift pump and related components are functioning—play a critical role in mitigating risk.

Common symptoms of a failing HPFP on the 6.7

Before listing symptoms, here is a quick overview of what owners often notice when the HPFP is failing or underperforming.

• Hard starting or extended cranking to start the engine


• Noticeable loss of power or sluggish acceleration, especially under load


• Engine stalling, rough running, or misfires


• Diesel knock or abnormal engine noises during idle or acceleration


• Illuminated check engine light with fuel-pressure-related diagnostic codes


• Reduced or fluctuating fuel rail pressure readings

These symptoms indicate potential HPFP or fuel-system trouble and should prompt a professional diagnosis. If you own a 6.7, addressing symptoms early can limit damage and cost.

Causes and contributing factors

Before listing the common causes, note that multiple issues can mimic HPFP trouble. The following factors frequently appear in discussions of CP4-related failures.

• Failure or wear of the CP4.2 high-pressure fuel pump itself, often leading to insufficient or inconsistent fuel pressure


• Debris or metal shavings from a failing HPFP contaminating the fuel rail and injectors


• Contaminated or poor-quality diesel fuel introducing abrasives into the fuel system


• In-tank lift pump (low-pressure fuel pump) failure, which can starve the HPFP of fuel and accelerate wear


• Clogged or restricted fuel filters and lines, reducing flow to the HPFP


• Improper or failed service work that leaves the system susceptible to pressure fluctuations

These factors can contribute to a higher risk of HPFP failure and may necessitate not only HPFP replacement but also downstream repairs or system flushes.

What to do if you own a 6.7 Power Stroke

Owners who experience or suspect HPFP trouble should take a careful, stepwise approach to diagnosis and repair. The aim is to confirm fuel-pressure issues, identify the root cause, and minimize collateral damage to injectors and rails.

• Have a qualified diesel technician perform a fuel-system diagnostic that includes fuel pressure tests, rail pressure data, and scan for related DTCs (diagnostic trouble codes)


• Inspect the high-pressure fuel pump (CP4.2) for signs of wear, leakage, or debris


• Check the in-tank lift pump for proper operation and verify the fuel supply to the HPFP remains steady


• Examine and replace the fuel filter as needed; consider flushing the fuel system if contamination is suspected


• Discuss with the dealer or a trusted shop about updated or upgraded HPFP options (some owners pursue CP4.3 or other corrected configurations) and any applicable warranty coverage

Because HPFP failures can lead to injector and rail damage, driving the vehicle with suspected CP4 issues is discouraged. Early diagnosis and appropriate parts replacement can prevent more extensive and costly repairs.

Ford’s response and current status

Public discussions and service communications have repeatedly highlighted CP4-related HPFP failures in the 6.7 Power Stroke. Ford and third-party service bulletins over the years have guided dealers to inspect, replace, or upgrade HPFP components when symptoms are present, and to check related fuel-system components (lift pump, filters, rails, and injectors). Coverage and options can vary by model year, mileage, and warranty status, so owners should consult a local Ford service department or Ford’s owner resources for current guidance and any applicable recalls or extended warranties.

In practice, many owners who address CP4 failures with updated components and a thorough system flush report improved reliability. However, the fundamental risk remains that a failing CP4 HPFP can cause significant, costly damage if left unresolved, so proactive diagnosis and timely replacement are essential.

Summary

The core fuel-pump problem on the 6.7 Power Stroke centers on the Bosch CP4.2 high-pressure fuel pump, which can wear, fail, or shed debris into the fuel system. Symptoms include hard starts, power loss, stalling, and abnormal injector/rail behavior. Contributing factors include lift-pump failure and fuel-system contamination. Diagnosis by a qualified diesel technician, followed by appropriate HPFP replacement or upgrade and system cleaning, is the recommended path to restore reliability and prevent costly engine damage. Owners should verify current warranty coverage and service bulletins with their Ford dealer for the latest guidance.

How to prevent CP4 failure 6.7 powerstroke?

To prevent CP4 pump failure on a 6.7L Powerstroke, you can install a CP4 disaster prevention kit to protect the rest of the fuel system, use quality diesel fuel and diesel additives to improve lubricity, and perform regular fuel filter changes. A disaster prevention kit reroutes debris so that a pump failure only requires replacing the pump and a filter, rather than the entire fuel system.
 
Proactive mechanical and maintenance steps 
This video explains the function of a CP4 disaster prevention kit: 55sFlying WrenchesYouTube · Apr 17, 2025

• Install a disaster prevention kit: This is the most recommended step to prevent a catastrophic failure. These kits reroute the high-pressure fuel so that if the pump fails, metal debris is caught in a separate filter, saving the injectors, fuel lines, and other components. 
• Change fuel filters regularly: Replace the fuel filters at least every 15,000 to 22,000 miles or according to your owner's manual to ensure clean fuel reaches the pump. 
• Use quality fuel and additives: Always buy diesel from reputable sources to minimize water and contamination. Additionally, use a diesel fuel additive with good lubricity to compensate for the low lubrication in U.S. diesel fuel, which can reduce friction in the pump. 

During a potential failure

• Recognize the signs and shut it down: If you notice any signs of a problem, shut the engine off immediately to prevent the failure from spreading and causing more damage. Continuing to run the engine can grind metal into every part of the fuel system. 
• Consider proactive replacement: Some mechanics suggest replacing the CP4 pump proactively around 150,000 miles to avoid a potential catastrophic failure, though failures can happen sooner. 

What is the biggest problem with 6.7 power stroke?

The biggest problems with the 6.7 Powerstroke include fuel system issues, such as CP4 injection pump failure (especially on pre-2020 models), and emissions system problems like clogged EGR coolers and faulty EGT or NOx sensors. Other common concerns are leaks, often from the upper oil pan or the cold-side charge pipe, and issues with the high-pressure fuel pump.
 
This video explains some of the common problems with the 6.7 Powerstroke, including injection pump failure: 48s8020 AutomotiveYouTube · Dec 27, 2022
Fuel system 

• Injection pump failure: The Bosch CP4 injection pump on pre-2020 models is a major issue. It can fail due to metal-on-metal contact, sending metal shavings throughout the fuel system and causing extensive damage to injectors, lines, and regulators. 
• Fuel filter housing: The secondary fuel filter housing can leak, particularly the plastic fuel filter housing fitting, which can also be a fire hazard if it breaks. 

Emissions system

• EGR cooler: The EGR cooler is prone to clogging from carbon deposits, which can lead to a loss of power and may eventually require replacement. 
• EGT and NOx sensors: These sensors are known to fail, which can trigger a check engine light or even cause the vehicle to shut down. The middle EGT sensors are the most common failure points. 

You can watch this video to learn more about common EGR cooler problems: 58sPower Stroke MaintenanceYouTube · May 12, 2023
Leaks and other issues

• Oil leaks: A significant number of leaks are reported, especially from the upper oil pan and front cover, often caused by a clogged crankcase filter that builds excessive pressure. 
• Charge pipe failure: The cold-side charge pipe is a common failure point that can leak, leading to a loss of boost pressure. 
• Exhaust manifold: The exhaust manifold is infamous for cracking, which can cause exhaust leaks, a ticking noise, and a loss of performance. 
• Turbocharger issues: Early models had issues with the turbocharger's ceramic ball bearings, though updates were made in later years. 

This video shows examples of Ford 6.7 Powerstroke problems, including rad leaks and EGR issues: 1mJT2JZYouTube · Mar 8, 2024

What are the symptoms of a fuel pump failure on a 6.7 powerstroke?

Loss of power, decreased fuel efficiency, rough idling, and unusual noises are all red flags that indicate potential issues with the fuel pump. Ignoring these symptoms can lead to more severe damage and costly repairs down the line.

What are the symptoms of a CP4 failure on a 6.7 powerstroke?

CP4 Pump Failure Symptoms
Here's what to look out for: Engine cranks but won't start: If the pump grenades mid-drive or on startup, the fuel pressure will drop too low to fire the injectors. Reduced engine power: If the internal damage is just starting, you might feel sluggish acceleration or poor throttle response.