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5 Signs that Indicate Diesel Injector Failure

While extraordinary technological advances were made with the advent of the modern common-rail diesel injection system, new common-rail systems are subject to extreme operating conditions, making them susceptible to injector failure.

If proper maintenance is performed and problematic practices are avoided, the vast majority of diesel owners will go thousands of trouble-free miles without a problem. However, when compared to older diesel injection systems, modern common-rail diesel injection systems often present more challenges for vehicle owners due to the fact that they can fire two to three times per engine cycle.

This is because older diesel injection systems only use about half the fuel pressure modern engines do, and older injectors send the fuel through much larger passages. Modern common-rail diesel injectors also fire two or three times per engine cycle, which doubles the wear on the injector compared to diesels of the past.

With that in mind, let's take a look at the most common symptoms that might indicate that a diesel injector is failing.

  • Trouble starting the vehicle or uneven idling. The engine cranks but doesn’t start unless you crank it for a long time or it uses different speeds of revs on idle.

  • Misfire. If the vehicle misfires on ignition, a complete diagnosis involves finding the combustion process element that is lacking, which is either lack of fuel injection or a lack of combustion chamber heat. There is a low level of fuel being pumped into the ignition or the fuel charge in one of the cylinders fails to ignite.

  • Smell of fuel. The smell of diesel indicates a leak somewhere. This could be from a failing fuel injector allowing fuel to flow out of the injector when it isn’t active.

  • Dirty emissions. Today's common rail systems are extremely susceptible to contamination due to the extreme conditions they operate within. Contaminated or clogged filters and injector deposits cause an uneven or incomplete fuel burn, resulting in a dirty area around the exhaust and the release of white smoke from the exhaust pipe.

  • Increased fuel consumption and poor miles per gallon. Faulty injectors burn more fuel and will directly impact your vehicle’s performance and efficiency.

These symptoms, and injectors that are dirty, clogged, or have a leak, should not be ignored. If your vehicle has over 100,000 miles on it without replacing the fuel injectors, it is time to have them checked out by a trusted professional.

In the event that the injectors must be replaced, explore GB Remanufacturing's line of premium remanufactured diesel injectors that are remanufactured and re-engineered to perform better than OEM diesel injectors. With over 200 diesel part numbers and coverage from 1968-2021 for popular Dodge/Ram, Ford, GM, and Navistar applications, GB Remanufacturing's light and medium-duty diesel fuel injection program has you covered.


Curious to learn more? Visit our Knowledge Center, packed with fuel-injection related articles and topics to assist you in better understanding fuel injection systems and technologies.


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