How long do fuel injectors last?

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Fuel injectors are a key part of modern automotive systems, as they're responsible for getting gasoline into the engine in a precise, orderly and carefully engineered pattern. In general, they're expected to last a pretty long time. Both Bosch and Delphi, two major manufacturers of automotive components, say their fuel injectors have a life expectancy of 1 billion cycles. Essentially, that means that the fuel injectors should last as long as the car does.

So why, then, is this even a matter for discussion? How do fuel injectors fail? And, perhaps most importantly, is your mechanic trying to pull a fast one on you and your sputtering engine?

Unfortunately, the conditions you drive in are not ideal. Pollution is in the air, and fuel can be contaminated with water, dirt particles and other debris. Even though injectors are designed and tested in factories where engineers compensate for real-world factors, there are always unknowns and variables. Gasoline of unreliable quality, destructive driving circumstances (such as stop-and-go traffic) and your car's overall condition can add up, causing premature fuel injector failure.

You can delay the degradation process with a few simple steps that take no longer than a regular fill-up, such as buying high-quality fuel. Though all passenger car fuel is theoretically formulated to prevent grimy buildups, different brands and blends do have an impact on your car's performance. So do your driving habits -- short trips and frequent stops allow more fuel debris to accumulate, since it tends to stick when the engine is idling or turned off often. Look for higher-quality gasoline blends that claim to help maintain a cleaner engine by including detergents that prevent deposits.

Regularly changing your fuel filter (according to your vehicle manufacturer's recommendations) will help keep debris from circulating. You can also add fuel injector cleaner to your gas tank, which may help solve running issues such as sputtering. Doing this at regular intervals of 10,000 miles or so might provide more cleansing than your engine actually needs, but it won't harm the system [source: Allen]. Keep in mind, though, that while fuel injector cleaner can help restore your car's performance so that its power and mileage are closer to new, it can't improve your car beyond its original specs [source: Allen].

Even the best kept fuel injectors can be prone to trouble, though. The next section will discuss what you should do when your injectors are too fouled up to keep things going.

Faulty Fuel Injectors

If your fuel injectors are on the fritz, you'll definitely notice a difference when driving. Left unchecked, faulty fuel injectors can damage an engine enough to keep the car from running, but there's usually time to intercept and fix the problem.

Faulty fuel injectors on late-model cars will make their presence known by causing a cylinder to misfire. This is because on newer fuel-injected systems, the injectors work in sequence, and when the engine misses a dose of fuel, it won't run smoothly and may suffer damage over time. It's less of a problem in older cars featuring simultaneous injection systems, because good fuel injectors can sometimes compensate for weaker injectors, allowing the engine to recover its sequence more quickly.

Still, faulty injectors can't be overlooked or ignored for long. Dirty or worn-out injectors can also cause preignition or detonation [source: Carley]. Detonation is a fairly common problem in which gas remaining at the end of the normal air/fuel burning cycle (which is set off by the spark plug) spontaneously combusts. Detonation is harmless in some cases, but the pressure has potential to break engine components and cause pitting and scuffing around the pistons. Preignition is when the air and fuel combust before the spark plug fires, causing severely increased engine temperature and damaged pistons. This problem is much more likely to pinpoint a leaky injector than detonation is, because it's a relatively rare occurrence in fuel-injected engines.

Leaky injectors can also cause the car to flood -- that's when the engine is shut off with excess fuel trapped in the system. The fuel then vaporizes, settles and purges when the car is restarted, which can cause extensive damage [source: Allen].

Try cleaning your injectors before considering a replacement [source: Carley]. When replacement is the only option, take heed: At the very least, you'll need to replace only the faulty injectors [source: Carley]. They can cost several hundred dollars apiece, depending on your car, but you can ask your mechanic to look for rebuilt or remanufactured OEM (original equipment manufacturer, or factory quality) injectors to pare down the cost.

Whether your injectors are new or old, now's the time to start a preventive maintenance regimen. Read on to the next page for lots more about fuel systems and taking care of your car.

Related Articles


  • Allen, Mike. "Auto Clinic." Popular Mechanics. June 26, 2006. (Accessed July 20, 2010)
  • Allen, Mike. "Auto Clinic Expert Q & A -- Fuel Injection." Popular Mechanics. October 1, 2009. (Accessed July 17, 2010)
  • Allen, Mike. "Fuel Additives, ABS Lights, Fuel Injections, Stuck Pedals and Timing Belts: Mike Allen's Weekly Auto Clinic Online." Popular Mechanics. October 1, 2009. (Accessed July 20, 2010)
  • Carley, Larry. "Tech Tip: Diagnosing Fuel Pumps and Injectors." Import Car Magazine. November 13, 2008. (Accessed July 20, 2010)
  • Cline, Allen W. "Engine Basics: Detonation and Pre-Ignition." Contact! Magazine via Streetrod Stuff. January-February 2000. (Accessed July 20, 2010)
  • Delphi. "Delphi Multec Gasoline Multi-Port Fuel Injectors." (Accessed July 21, 2010)
  • Pro Flow Technologies. (Accessed July 21, 2010)