By Mike McGlothlin
The fuel injectors inside your engine are everything. Without them functioning properly, the performance of the car, truck, or SUV you drive will suffer. When the operation of a fuel injector is compromised, your vehicle could make less horsepower, see a decrease in fuel economy, a downturn in overall drivability, and produce increased tailpipe emissions—or a combination of all of those things. However, with proper care your fuel injectors can last hundreds of thousands of miles. Regular fuel system maintenance, as well as ensuring clean fuel is always in the tank, can play a large part in injector durability, and further protection can be had by running a quality fuel additive and performing periodic fuel system cleanings.
Fuel System Basics
Every modern internal combustion engine employs a fuel system that consists of a fuel pump, filter(s), and fuel injectors. Many late-model gasoline and diesel engines both utilize high-pressure direct injection, with diesel power plants seeing in-cylinder injection pressures as high as 30,000 psi. Direct injection and higher pressures are key reasons why modern domestic gas and diesel engines are able to meet the most stringent tailpipe emissions in the world. Additionally, today’s high-tech fuel injectors work to curb noise and NVH while also facilitating the highest horsepower figures ever seen in U.S. automotive history.
Fuel Injectors—The Modern Marvel Inside Your Engine
Today’s high-pressure fuel injectors are electronically controlled, boasting lightning-quick actuation and deactivation. These near-instantaneous on and off times enable the most precise injection events possible, which has allowed auto and engine manufacturers to build the cleanest and most powerful vehicles on the planet. For example, Ford’s high output 6.7L Power Stroke—a diesel V-8 equipped with piezo electric fuel injectors and a 36,000-psi high-pressure common-rail injection system, already meets 2027 EPA federal particulate matter (PM) standards while simultaneously turning out 500 hp and 1,200 lb-ft of torque.
Why Your Fuel Injectors Are So Vital
AGX1W6 Side view of spray from a diesel engine fuel injector. Image shot 2006. Exact date unknown.
In many diesel applications, the fuel injectors carry out five or more injection events per combustion cycle (i.e. each power stroke). In order to function at their peak potential, fuel injectors must be kept in tip-top shape—this means clean, high-quality fuel and routine filter changes are mandatory. Fail to do this and you’ll get lousy performance, poor fuel economy, increased emissions and, eventually, a steep repair bill when the injectors (or fuel pump) quit working. Today’s fuel injectors feature microscopic internal passages (i.e. ultra tight tolerances)
when compared to the injectors of old, and they do not tolerate deposits or debris—even in the most miniscule of forms.
Don’t Take Them For Granted
It’s no secret that the cutting-edge engines produced today are built with expensive components, and this is especially true regarding the fuel injection system. As we previously alluded to, injector failure is costly. This is because modern fuel injectors, with so many jobs to do, are equipped with electronic solenoids and utilize exotic internal components such as DLC coated nozzles, needles, plungers, and thrust plates in order to last. Outside of high miles, most injector failures are traced back to maintenance neglect. Warranties are voided every day due to lack of (or improper) fuel system maintenance, and many warranty claims are also denied due to contaminated fuel, such as water-laced diesel fuel.
Symptoms Of An Injector Issue
Poor performance, such as a rough or inconsistent engine idle, lack of power, and a loss in fuel economy, are often associated with fuel injector failure. However, an engine that’s hard to start or one that stumbles or even dies is a common occurrence as well. Higher tailpipe emissions can be a good indicator, but it can be harder to detect on modern diesel engines equipped with exhaust aftertreatment systems. One of the most frequent findings with fuel injector failure becomes evident once a scan tool is connected to the OBD-II port and reveals unlevel injector balance rates.
Bad Injector Indicators:
*Poor engine performance
*Rough/inconsistent idle
*Hard starting
*Engine stalling or stumbling (missing)
*Decreased fuel economy
*Increased tailpipe emissions
The Many Faces Of Fuel Injector Failure
As with a lot of engine problems, fuel injector failure runs the gamut in terms of what specific component gives way. Below, you’ll find a list of the parts that fail most often inside a fuel injector, along with the most commonly observed injector-related issues:
*Failed internal high-pressure injector seal
*Incorrect nozzle needle clearance
*Excessive needle lift
*Improper nozzle flow balance
*Seized nozzle needle
*Damaged nozzle needle seat
*Cracked nozzle
*Partially clogged nozzle
*Cracked injector body
*High mile or damaged injector ball seat
*Leaking cross tubes
Causes Of Injector Failure
Sources of fuel injector failure vary as well, but internal wear typically occurs due to age, low-quality fuel, or deposits within the fuel. Deposits often lead to plugged nozzles or unnecessary wear and tear, but abrasion—the microscopic impurities that exist in all fuels—has the potential to cause excessive damage in fairly short order. Other fuel injector failures tend to result from incorrect assembly (think of a remanufactured or refurbished set of injectors) or poor-quality parts. When top-quality components are not employed in a fuel injector rebuild, early failure is commonplace.
Injector Cleaning (Gasoline Engines)
Screenshot
For late-model gasoline engines, it’s ideal that they undergo a fuel system cleaning every 25,000 to 35,000 miles. It’s a procedure that can consist of comprehensively cleansing the fuel lines, rail(s), pressure regulator, fuel injectors, throttle body, and even the vacuum line(s). Most fuel system cleanings remove carbon buildup from the intake manifold, throttle body, intake and exhaust valves, and even the combustion chambers. Some injection system cleaning services also offer pressure testing of the fuel pump and fuel system. It’s a process that’s geared toward maximum fuel system longevity, which ultimately translates into improved overall engine longevity.
Injector Cleaning (Diesel Engines)
For modern diesel engines, comprehensive fuel system cleanings aren’t as common, though they do exist (more on them later). Instead, the primary source of fuel system care entails regular fuel filter maintenance (i.e. replacement), keeping quality fuel in the tank, and using a reputable, proven fuel additive—one with detergent and dispersants that help control deposits. Finding tiny deposits, rust, carbon, or other debris in a plugged-up diesel fuel injector nozzle is a frequent discovery. Luckily, the right fuel additive can rid the fuel system of these contaminants before they become a problem or (worse) cause irreparable damage inside the fuel injector.
Complete Engine Cleaning (Diesel Engines)
Though not performed as frequently as it is on gasoline engines, there are select complete engine cleaning services available for diesel owners. Most of these cleanings serve to purge the fuel, oil, and emissions systems of soot, carbon, debris, and deposit buildup. They’re known to do a good job dissolving internal injector deposits, can reduce exhaust aftertreatment regeneration intervals and also serve to keep the EGR system operating on the up-and-up. As we alluded to above, running a reputable diesel fuel additive is a key part to preserving the life of fuel injectors, and it’s something that is included when performing a full-on diesel engine cleaning service.
How To Keep Your Injectors Alive For The Long-Haul
With the right combination of clean fuel, routine maintenance, and a reputable additive in the tank, the fuel injectors in your diesel or gas engine will live a long, healthy life. In light-duty diesel applications, this recipe for care is known to glean at least 200,000 miles from a set of high-pressure common-rail fuel injectors. Of equal importance, it’s vital that you address any fuel-related issues with your engine immediately. Never take chances or delay repairs with a $15,000 - $20,000 injection system. The reward for proper upkeep and attentive eyes and ears is increased injector life, decreased emissions, more up-time, fewer repairs, and a safer experience out on the road.
Methods Of Maintaining Your Injectors:
*Regular fuel system cleaning service (gasoline engines)
*Run a reputable, high-quality fuel additive that contains detergent and dispersants
*Only fill up at high traffic fuel stations with quality diesel or gasoline
*Perform fuel filter changes at (or before) manufacturer-specified intervals
*Immediately address any fuel system and/or engine-related issues
*Avoid allowing air to enter the fuel system (properly prime the system following repairs or filter changes)
