Diesel Engine Common Rail Injectors: Potential Failures & Causes

You've just been told that you need to replace your diesel engine fuel injectors. 

But what exactly caused the failure that led to this point? 

There are several things that could cause problems with your diesel engine common rail fuel injectors, including poor fuel filtration, fuel contamination, improper installation, and the use of non-OEM quality remanufactured parts.

We're taking you through each of these problems so you can better understand what's going on in your engine, and so that you can better prevent these problems in the future. 

Need more information on common rail fuel injectors? Check out our blog on the differences between common rail and unit injectors.


Looking for replacement common rail injectors? Highway & Heavy Parts carries Bosch injectors! Call our ASE Certified Techs and let them help you get the right injectors for your engine.

Give Us A Call!


Poor Fuel Filtration

One of the main problems you might be having with your common rail fuel injectors is poor fuel filtration. 

A common issue you'll see with these systems is ball seat erosion. This can occur when the small ball that seals the passage of the magnetic valve at the heart of the common rail injector is not sealing properly. A correct seal is vital for proper function, so when abrasive contaminants erode and damage that ball seat, you won't be getting proper injection. 


ball seat erosion graphic | Highway & Heavy Parts


If this happens in your diesel engine, you might notice:

  • Excessive Smoke
  • Starting or Idling Problems
  • Potential Engine Failure


new valve body graphic | Highway & Heavy Parts


To help ensure that your common rail fuel injection system functions properly, use filters that have the same micron rating as the OE filters. Be sure to follow the oil change interval recommended by the OE. 


Fuel Contamination

Did you know that a large number of diesel engine problems are caused by contaminated fuel? This is true of fuel injectors as well. Another major problem you can have with your common rail fuel injectors is corrosion caused by water contaminating the fuel. 


injector corrosion 1 graphic | Highway & Heavy Parts


This contamination can be the result of water entering a fuel storage tank. These tanks have a vented cap that allows air to enter, equalizing pressure as fuel is removed. This air is obviously from the outside, and contains moisture. So, as this air enters the tank, the moisture condenses into water inside the tank. 


injector corrosion 2 graphic | Highway & Heavy Parts


Fuel contamination symptoms include:

  • Poor engine performance
  • Engine idling problems (vibration)

To help prevent this problem, make sure you're purchasing fuel from a reputable provider. Using the correct fuel/water separator can also help prevent contaminated fuel from damaging your diesel engine. 

Read our blog post to learn other problems fuel contamination can cause your diesel engine. 


Improper Installation


combustion residue graphic | Highway & Heavy Parts


Installation problems can also cause a failure in your common rail injectors. This can range from missing sealing rings, to incorrect tightening torque, to incorrect cleaning of the nozzle. Improper installation techniques can cause:

  • Poor Performance
  • Engine Misfiring
  • Black Smoke
  • Check Engine Light (MIL)


solenoid stud graphic | Highway & Heavy Parts


Problems from incorrect installation can be avoided by always following your engine manufacturer's maintenance instructions.


Non-OEM Quality Remanufactured Parts

As we've mentioned before, not all remanned parts are created equal. Some will give you more problems than they're worth. The quality of the injector depends on the remanufacturing process and the components that are replaced in it.

Sometimes, an injector will be marketed as rebuilt, but really it was only refurbished. Want to know what the difference is? Read our post on the difference between refurbished, rebuilt, and remanufactured

You'll probably get a good deal on these parts, but they won't keep your engine running in peak condition. 

To avoid this problem, make sure you're buying OEM quality remanufactured injectors. Here at HHP, we're proud to carry Bosch common rail fuel injectors. These injectors are the same as OE in design, engineering, materials, manufacturing, and quality control. They meet all the latest emission requirements and include all the OE updates, so they might even be better than the ones you're replacing. 


Why take a risk on your common rail fuel injectors? Let Highway & Heavy Parts get you the best quality replacement injectors for your diesel engine. 

If you need fuel injectors for your diesel engine, we have ASE Certified Technicians on staff ready to help you out! Call us at 844-304-7688, or request a quote online!