6.5 Diesel Injection Pump Failure Symptoms [with fixes!]

An injection pump in 6.5 diesel can take you around 100,000 to 200,000 miles before giving up. However, it doesn’t mean the device will always work smoothly, especially when it’s attacked with damage and dirt.

Some common 6.5 Diesel Injection Pump Failure Symptoms include:

• Engine misfires
• Surges
• Power Loss
• Difficulty starting and
• Gas smell

Besides the warnings, I’ll let you know how they show up and how to deal with them. 

4 common 6.5 Diesel Injection Pump Failure Symptoms

Several warnings help indicate whether the injector pump in 6.5 diesel is bad. Out of them, I found these 5 to be very common symptoms of injection pump malfunctioning. 

1. Engine Misfires

It’s one of the earliest signs of 6.5 diesel injector pump failure. 

The vehicle runs smoothly at 10 to 50 miles/hour. But as acceleration increases, there might be a brief episode of sputtering, especially when you’re on backroads or highways. Such disturbance can continue for 2 to 50 minutes (depending on the severity) before going back to the normal state.

One of the biggest reasons why the jerk happens is that the injection pump on 6.5 diesel is clogged and going bad. The damage causes it to-

• Have a drop in pressure
• Mismanage injection timing
• Send improper air-fuel mix or just air to the combustion chamber. 

This all creates a disruption in flow, triggers the engine to skip power strokes, and forces it to sputter. 

Read also: 4 Most Common 6.4 Powerstroke EBP Sensor Symptoms – (Fixes!)

2. Start Issues

One of the most common 6.5 Diesel injector pump failure symptoms is the engine experiencing start issues. 

A bad pump can hamper the flow preventing engine from getting sufficient gas. Although ignition may work and create enough spark, the engine may not start. A very big reason should be dirty pumps which can lead to damage if left uninspected. 

3. Power Loss

Any damage to 6.5 diesel injection pump can lead to loss of power. 

It may happen when you try to accelerate on highways, tow a load, or climb a hill. All these put extra strain on pump and engine making the latter require more fuel to make up for it. 

So when the pump malfunctions, it creates less pressure in lines of fuel. While the injector works harder, it fails to meet the demand for increased gas. This makes the engine starve resulting in power loss. 

Although these signs are more common in older vehicles, some newer models with 6.5 diesel may experience it too. 

4. Engine Surges

Call it a dangerous sign of failing 6.5 diesel injector pump. Such a faulty device can result in a sudden surge of power. 

This happens mostly because of clogged injectors and may deteriorate in case you don’t check on time. If affected, it can trigger the pump to supply either excessive or less fuel to combustion chamber. Subsequently, the vehicle may speed up or decelerate even if you try to control it. 

It’s pretty risky since it can cause accidents, especially if the symptom strikes on highways. 

Plus, faulty injectors burn more fuel. Hence, you have to deal with poor efficiency and performance too.  

5. Diesel-like Odor

Getting a smell of gas fumes is another sign you have a bad 6.5 diesel injector pump. 

One reason behind this odor is the crack in the O-ring seals at the tip of the nozzles or the injector. This may happen over time since injectors hold a high amount of pressure. So when there’s damage, it triggers the injector to oversupply fuel since it can’t close on time or leak fuel. These end up giving off a diesel like smell. 

These leaks can bring up other symptoms such as affected fuel efficiency and engine performance. 

troubleshooting 6.5 Diesel Injector Pump Failure issues

Dirt and physical damage are two common causes of faulty injector pump in 6.5 diesel. To help you out, let me tell you some effective tips on 6.5 Diesel injector pump troubleshooting. 

1. Clogged Injector Pump – Remove dirt with a cleaning kit 

Injector pump in 6.5 diesel can get dirty over time. Contaminants like old/low-quality diesel, carbon/soot, grease, grime, gunk, and different particles coming from fuel or the system make the injector filthy and clogged. Not just that, they can block the fuel spray tip too. 

I suggest you clean the injector pump properly with fuel injector cleaners before it malfunctions. Speaking of which, cleaning fluid with polyetheramine (PEA) is an efficient method. It’s a nitrogen-based detergent that helps dissolve stubborn carbon and lacquer deposits. 

2. Physical Damage and Leaks – Repair leaks or replace the injector pump

Impurities, clogs, corrosion, and lack of oil change can damage injector pump directly or indirectly. However, some of the devices may come with defects from the factory. 

If it’s some parts like O-rings and ball seats that broke, then you need to fix or replace them. Because when they are affected, it causes the 6.5 diesel injection pump to supply fuel at the wrong time. 

In case the damage is serious and creates troubles like fuel leaks along with incorrect timing, then I advise you to rebuild or replace the pump completely. 

3. Contamination Inside Injector – Use fuel cleaner additive and clean the injector.

I’ll continue this part from the first cause. Injector pump can get contaminated due to sediments, filths, clogs, and bad fuels. 

6.5 diesel injection pump is designed to deal with great amount of stresses and motions. It requires everything neat to work properly. 

However, a tiny foreign particle gets inside and it can mess up the system, stopping injector from closing. If injector doesn’t open and close properly, it may lead to failure. On top, it lowers cylinder performance. 

Check the root of the problem first. If it’s a dirty fuel, adding some fuel additive will help you get rid of unwanted particles. Apart from this, clean the injector properly as I mentioned in the first cause. 

4. Clogged Air Filter – Clean it with a cleaner and replace it when needed. 

Clogged air filter can damage the injection pump in 6.5 Powerstroke diesel. Similar to the injector, contaminants can foul air filter over time and turn it black or dark brown. As the filter gets super dirty, it clogs the path. And consequently, it prevents injection pump from getting the required amount of air to operate the engine smoothly. 

Hence, clean the air filter regularly. A solution of water and mild laundry detergent is enough to do the job as it does for me. A very efficient way is to use an air filter blaster or cleaning kit. I also suggest you replace it every 12,000 to 15,000 miles. This will help keep the system well-functioning. 

5. Low Fuel Level – Tow the car to the service spot and fill up the tank

Fuel acts as a lubricant for the injection pump bearings. If the tank has low level of fuel, it prevents both injectors and engine from running properly. Result, both the engine and pump may get damaged. 

Make sure to fill up the tank whenever the indicator lights up. To be on the safe side, I recommend you refuel when there’s a quarter or half of the tank left. 

Frequently Asked Questions (FAQs)

1. How To Test A 6.5 Diesel Injection Pump?

Checking the fuel volume and pressure is an efficient way to test a 6.5 diesel injection pump. 

Keep your engine running and open the T valve. Then, drain the fuel and observe. It should take 30 seconds for the fuel to be released at 1,500 psi. If the engine dies before that, then injection pump might have some problems. 

2. What Does A Bad Injector Pump Sound Like? 

If there’s an unusual jerking, rattling, or taping sound, then this may indicate a faulty injector pump. 

Although some noises are normal, the prominent one is when engine misfires and ends up sputtering. 

3. How Much Does It Cost To Replace A 6.5 Diesel Injection Pump?

It may cost around $350 to $2,400 to replace a 6.5 diesel injection pump. 

Here, the cost depends on the quality of injector pump, whether it’s the parts or whole needed to be replaced, and time of labor. The service fee may range from $400 to $1,000 and parts may take around $650 to $1,800.

in Conclusion 6.5 Diesel Injection Pump Failure Symptoms

Having a safe driving habit and taking care of the injection pump along with the system is a must. These two are the only methods that help prevent injector pump problems symptoms in 6.5 diesel. 

You must clean the device at least once every 2 or 3 years. Also, don’t forget to replace it whenever it starts failing. Because showing carelessness can lead to severe damage and safety hazards. 

Video References

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Iyul Nasruddin

Nasruddin is a passionate car enthusiast with a love for troubleshooting and diagnosing all sorts of vehicle problems. With years of experience in OBD diagnostics, Nasruddin, has become an expert in identifying and solving complex automotive issues.