5 Symptoms To Detect CP4 Failure On 6.7 Powerstroke Engine

Though the 6.7 Powerstroke CP4 injection pump is designed to supply constant high-pressure fuel to help the engine run smoothly, it has become a frustrating component for many 6.7Powerstroke owners and users. 

Many users have experienced CP4 failure, but they could have prevented the problem if they were aware of the initial sign and symptoms to get a hint. 

Therefore, in this very article, let’s learn how to detect when your CP4 needs immediate attention.

What Is The Sign Of 6.7 Powerstroke Engine’s CP4 Failure?One of the most common and obvious signs of 6.7 Powerstroke cp4 failure is when your engine suddenly starts to jerk or sputters especially, at high speeds and lose power while on acceleration.

5 Symptoms To Detect CP4 Failure On 6.7 Powerstroke Engine

There are other significant symptoms by which you can easily identify when your exhaust backpressure sensor needs proper inspection and repairing or replacement. 

So, let’s learn more about those symptoms and how to detect 6.7 powerstroke engine’s cp4 failure:

1. Sputtering At High Speeds, Stalling & Power Loss

CP4 failure means the high-pressure fuel pump on your 6.7 Powerstroke engine is enable to generate enough constant flow of gas. 

Therefore, when you turn your vehicle at high RPM speed, the engine visibly starts to jerk or sputter and eventually stalls. 

When the CP4 fails, it leads to transmission fluid leakage, which also may occur due to a fault in transmission filter fitting. 

You can easily notice the leakage issue while moving your vehicle from the parking position. 

Another common symptom that directly indicates the CP4 or high-pressure fuel pump failure is when you notice a significant loss of power. 

Especially while on acceleration, driving up a slope, or even during towing engine will constantly lose power. 

Generally, you will not have any issue shifting into different gears, and the transmission will respond actively in each gear. 

But when it hesitates while shifting into particular gears, it means you need to check the fuel pump condition.

2. Reduction Fuel Efficiency & Gas Mileage

When you notice a significant reduction of fuel efficiency or gas mileage, that is another clear warning sign that something is wrong with your transmission fluid or CP4 Fuel pump. 

When the fuel pump fails to operate as it supposes to, it pushes too much fuel into the engine. 

As a result, you will be forced to use or burn more gas than regular. 

As soon you notice a significant drop in your engine’s gas mileage or fuel-efficiency, make sure to check the transmission fluid whether it turn brown or yellow.

3. Engine Starting Difficulty

When the fuel pump fails to act accurately and transmission fluid starts leaking, it eventually affects the engine to start or run smoothly like usual.

Therefore, whenever you notice that your engine is struggling or having difficulty starting and run, check the CP4 condition first. 

Although starting difficulty can occur because of other reasons or technical errors, still, the fuel pump does play an important role in the engine’s starting performance.

4. Engine May Surge Or Fails To Fire Up

If you notice that your 6.7 Powerstroke engine is surging while the acceleration is not engaged or the engine is failing to fire up, that can be a possible indication of the CP4 performance failure.

Since when the fuel pump fails, it also loses the fuel line pressure and cannot provide enough fuel for the engine to fire up.

Even when the transmission filters get clogged because of the excess contaminants, you may smell burning fragrances or see smoke coming out from the engine.  

5. Rise In Temperature & Rattling Noises

You may hear a loud whining sound coming from your engine’s gas tank when the CP4 or high-pressure fuel pump of the 6.7 Powerstroke fails.

Sometimes the fuel pump makes such noises when you are out of fuel or have dirty contaminated fuel mixture in your gas tank. 

So, better to inspect to verify the issue.

Even while driving, if you hear a slight rattling noise coming from the filters or your engine may heat up, check your transmission system’s condition. 

It can be either because of a loose connection or blockage so, make sure to inspect.

These are the most commonly identified symptoms that indicate the CP4 failure condition. So, if you also own one of the 6.7 Powerstroke engines on your vehicle, make sure to keep them in mind.

What to Do When You Detect 6.7 Powerstroke CP4 Failure  ?

Whenever you encounter any symptoms indicating that your CP4 pump may failed or has any damage, make sure to follow the below instructions in order to fix the problem-

Check Fuel Level Of The Gas Or Fuel Tank:

The first thing you should inspect is the fuel level on your fuel or gas tank. 

Sometimes people assume that they have sufficient fuel and blame other components for functional error. So, make sure at least more than 1/4 fuel tank is filled up with clean or fresh fuel.

Inspect The Fuel Filters & Replace The Filter, If Required:

Another very common scenario that most users encounter is the fuel pump fails because of the clogged or damaged fuel filter. 

Therefore, you need to check and replace the filter, if needed.  

Sometimes even after changing the filters, you may notice that the fuel pump is still not responding smoothly. 

It can happen when your fuel system priming task goes wrong. So, make sure you are priming the fuel system correctly. 

You may need to pump the plunger so that it gets firm enough to bleed at the Schrader valve. 

It will ensure that no excess air exists in your fuel system and prevent the CP4 wear from getting damaged quickly.

Also, after replacing the filters, do not immediately start the engine to check and wait for at least 20 to 25 seconds.

Do A Data Reading Test With The OBD Testing Tool:

For this test, you need to purchase the OBD Tool to monitor the pressure level.

So, to investigate the reading, crank your vehicle and observe the reading result. 

The standard desired fuel rail pressure should be around 4000 to 5000 PSI maximum. 

But if your actual pressure reading shows 350 to 500 PSI results, it means your CP4 fuel pump has a high-pressure performance failure.

Fix Your CP4 Pump:

After all those inspections and testing, if you are sure that no other error is causing the problem and only need to fix your damaged or failed CP4.

All you need to do is completely rebuild or replace your vehicle’s fuel system, which includes replacing the fuel injectors, lines, rails, sensors, CP4 pump, fuel filters, draining and cleaning the fuel tank. 

It will also include removing cleaning and replacing the secondary fuel filter, filter lines, or housing.

Is Replacing A 6.7 Powerstroke CP4 Typically Expensive?

Fixing fuel pump failure or replacing the faulty pump with the new one is never a cheap deal. 

Since CP4 failure leads you to rebuild or replace the entire fuel system of your vehicle, it will be an expensive deal. 

The estimated cost owners have to bear for that replacement task is around $8,000 to a maximum of $10,000.

How Often Should You Inspect Or Service 6.7 Powerstroke CP4?

To prevent your 6.7Powerstroke engine’s CP4 failure, you should change or replace the fuel filters after each10-15,000 miles operation. 

You can also take some precautionary actions in advance, such as installing an EPA Compliant CP4 Disaster Kit. 

This one is highly recommended for Ford users and will protect your fuel injectors, lines & rails from the excessive amount of contamination. 

If your vehicle does not have any factory lift pump installed, install a FASS fuel system to support your CP4 Pump.

The Verdict

A high-pressure fuel pump or CP4 is assigned to pump the fuel from the gas tank to the engine and maintain a constant steady flow. 

Therefore, any slight malfunctioning issue with CP4 is real bad news, but prevention can help you keep your CP4 healthy, and those above discussed symptoms will help keep a close eye on your CP4 to prevent any severe issue.

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