6 Diesel Fuel Injector Testing Questions and Answers
As diesel emissions specialists, we receive a wide range of questions regarding the maintenance, cleaning, and testing of diesel fuel injectors. To best serve our customers, we’ve compiled the top questions we’ve received into this handy Q&A blog.
Read on to get your diesel fuel injector questions answered - courtesy of Lynx Emissions.
What do Diesel Fuel Injectors Do?
Injectors are essential components in diesel-fueled internal combustion engines, as well as the exhaust aftertreatment system of these engines. The specific function of these injectors changes depending on where in the system the injector is located. Here are a few of the different areas, as well as the function that the injector serves:
Engine Fuel Injectors: These diesel fuel injectors deliver the right amount of atomized fuel to the engine cylinders at precise intervals, ensuring effective combustion and optimal engine performance.
Aftertreatment Fuel Injector: Some emissions systems from the Mid-2000s to Mid-2010s include fuel injectors as a vital part of the exhaust aftertreatment system. These additional injectors, commonly known as the “7th Injector,” help boost the exhaust gas temperature to allow carbon particulate to break down in the filter (regen). AFI’s supply atomized fuel to the exhaust stream before the DOC, which reacts with the precious metals within the catalyst, creating heat. On the oldest versions of exhaust systems with AFI’s, they sometimes do all of the heavy lifting if the system does not contain a DOC.
DEF Injector: While not a fuel injector, this injector still plays a vital role in your engine’s aftertreatment system. The DEF Injector sprays DEF fluid into the exhaust stream before the exhaust enters the SCR, turning toxic NOx particles into non-harmful particles (N2, CO2, H2O).
What are the Symptoms of Failing Injectors?
When a fuel injector starts to fail, your vehicle may show several symptoms, including:
Reduced engine power
Engine misfires
Rough idling or engine vibrations
Sluggish acceleration
Check engine light illumination
Lower fuel efficiency
Stalling
Difficulty starting the engine
Strong fuel odor from the engine
Increased emissions
Promptly addressing these symptoms can prevent further damage to your engine.
Why do Injectors Fail?
There are several different reasons why injectors fail, some of which can be solved:
Carbon buildup on Injector Tip: This can be resolved by cleaning.
Faulty Solenoids: Not releasing as much fuel as the ECU calls for.
Bad Fuel: Water in the diesel causing rusting.
Failure of parts upstream in the fuel system (Debris): Particles in diesel or a blown pump.
What is Injector Testing?
Injector testing is a process used to check the functionality and condition of diesel fuel injectors and DEF fluid injectors. This testing ensures that the injectors are properly pressurizing and injecting properly atomized fluids at the correct intervals, making it a crucial part of engine and exhaust maintenance.
Why Test Your Injectors?
Testing your injectors can provide several benefits:
Better Engine Performance: Ensures your engine gets the right amount of fuel.
Improved Fuel Efficiency: Saves fuel and money.
Lower Emissions: Helps your vehicle produce cleaner exhaust.
Prevents Engine Damage: Avoids problems that could harm your engine.
Smoother Driving: Reduces issues like misfires and rough idling.
Why Should Fuel Injectors Be Tested Before Replacing Them?
Testing diesel fuel injectors before replacing them has the potential to save you a lot of time and money. Here are the two main ways that this occurs:
Although you may suspect an injector is responsible for your machine’s troubles, it’s possible that the injector may just be a symptom of a larger issue further up the fueling system. Testing allows us to find out what is really happening under the hood.
If a fuel injector is dirty or clogged, your engine won't get the necessary flow of fuel, leading to poor acceleration, engine performance, and gas mileage. Testing helps diagnose whether the injector is the problem or if there's another underlying issue.
Not all injectors may have failed. Some injectors might just be too far out of spec compared to the rest of the injectors in the engine, causing an uneven firing order.
Why Do Injectors Need to be Tested by a Professional?
Professional testing of both diesel fuel injectors and DEF injectors ensures accurate diagnostics, meaning that you get a clear answer on whether the next step should be cleaning or replacement. Professionals have the right tools and expertise to detect issues that might be missed in a DIY approach. If your injector passes testing, they may be able to help advise where the source of engine issues stems from.
At Lynx Emissions, we offer meticulous testing, cleaning, and diagnostics for your fuel injectors and DEF injectors.
Failed injector? No worries! We also provide high-performing injectors and fuel pumps that meet OEM standards. If your injectors fail our tests, we have immediate replacements available with as little as a 1-day turnaround. Count on us to keep your vehicle running smoothly and efficiently.
Contact us today to let us take care of your fleets exhaust systems, so you can get back to focusing on what matters to your operation.
