Is your vehicle experiencing poor performance, reduced fuel economy, or rough idling at stoplights? It either has a terrible case of the Mondays or, more likely, it has some dirty fuel injectors.
Recognizing the symptoms of dirty injectors and getting a simple cleaning can eliminate the rough driving experience for a more enjoyable drive.
What Is A Fuel Injector?
The fuel injector is important for the modern automobile, as it is responsible for atomizing and injecting fuel into the combustion chamber. It is known as the “heart” of the engine.
The fuel injector is connected to the Electronic Control Unit (ECU), which is responsible for controlling the fuel injectors. The ECU varies the opening and closing of the solenoid valve to inject the fuel into the high-pressure fuel rail, which is injected into the combustion chamber so that combustion is as efficient as possible.
The fuel injectors inject atomized fuel directly into the combustion chamber. The fuel injected is referred to as fuel injection and utilizes the injector.
The fuel injection process enables maximum power while minimizing fuel consumption and pollution. Fuel injectors help reduce emissions through smaller droplet sizes of atomized fuel to achieve a more efficient burn.
Electronic fuel injectors are more reliable and efficient than in the past, by far, and are incredibly prevalent as a choice.
How Does The Fuel Injector Work?
A fuel injector consists of a solenoid, a nozzle, and an injector body. The fuel injector nozzle is machined to a high degree of precision. Like many other devices, the nozzle has an inlet and an outlet. The inlet draws fuel from the fuel tank, and the outlet delivers the fuel as a spray into the combustion chamber.
The overall fuel injection process allows for injecting fuel into the combustion chamber in an efficient and timely manner. Fuel injectors are usually constructed of stainless steel, and the injector has a plunger or valve that opens to allow fuel through or closes to stop fuel flow.
Also, the body of the injector is responsible for converting the electrical signal from the solenoid into the pressure needed to push the fuel through the nozzle. Once the injector opens, the solenoid is pulled up, and the resulting fuel will now flow through the nozzle and into the combustion chamber of the engine.
The fuel injectors come from the fuel rail, which holds the fuel that comes from the fuel tank, and connect to the injectors to read sensor data on how much fuel will spray into the engine.
Symptoms of a Bad Fuel Injector
Here are the most common symptoms of a fuel injector issue – just remember, the fuel injector may just be clogged, and you might not need to replace it.
Also, using a bottle of fuel injector cleaner can work, but doing a proper cleaning with a fuel injector cleaning kit is preferred before you spend the money on new injectors.
#1. Rough Idle or Stalling Engine.
Under-fueling or even-fueling the engine will cause the RPM at idle to be lower than optimal, resulting in an obvious rough idle or violent idle. If the RPM becomes too low, it could stall the engine, and you’ll have to try and restart it.
The rough idle is most pronounced when the engine is cold or sitting at a stoplight.
#2. Engine Vibrations from Bad Injectors.
Bad fuel injectors can cause specific cylinders in the engine to fire improperly and may cause the engine to begin vibrating noticeably.
If you are driving, there may be a rhythmic shaking (and you feel the shaking all the way through to the seat or steering wheel) or a hiccupping sensation if you are attempting to maintain a speed.
The shaking can go away as it is a result of the engine running normally, but it will return as it becomes uneven again, too.
This happens because the cylinder is not getting the right amount of fuel it normally would, causing the normal firing in the engine to run out of order.
The intensity at which the vibration is felt can vary depending on the bad injector and the severity of the application. You may also notice the vibration is worse at certain RPMs.
#3. Engine Misfires Caused by Clogged Fuel Injectors.
When a cylinder doesn’t fire properly, that’s called an engine misfire. Misfires can happen for several reasons, and whether due to a clogged or malfunctioning fuel injector, you will typically notice a hesitation or stumble when you try to accelerate, as if the engine suddenly lost power, and may feel a slight jerk or shudder in some cases.
While only a fuel injector should not be solely to blame for a misfire, it is often the blame or should be one of the first places to look for solving the problem. Anytime your car’s air/fuel ratio isn’t correct, you want to resolve it as soon as possible.
#4. Check Engine Light.
The most obvious sign that something is wrong with the car is when the “Check Engine light” turns on in the vehicle’s dashboard. Even with that, “check engine” can mean several things, and a bad fuel injector (specifically codes P0201, P0202, P0203, P0204) can be a big possibility.
So, if an injector delivers less fuel than needed, (or delivers more fuel as if to lower engine performance that could result in a cause difference in power for resetting for the season,) the operable efficiency of the engine is low, and performance issue (like a fuel injector could) could trigger the CEL to conscious right, so we suggest this is done with an OBD2 scanner.
#5. Fuel Leak.
If your fuel injector is broken, cracked due to damage or old age will leak through it. In some instances, you may find the underside of the fuel rail wet, if not gasoline on the ground below, depending on the sustained distance to take air inhalation elsewhere.
Most times, though, your leak leaked from a degraded or damaged seal at the fuel injection, and no matter how bad it is, it’s fuel, so it’s a hazard, safe, and timeline to repair.
#6. Fuel Smell.
This is along the lines of a fuel leak, but when you have gasoline that’s not being used because of a broken fuel injector or stuck open, you’re going to smell gasoline.
Maybe it’s your fuel lines, or even a defective sensor that is telling the ECM to add more fuel than what’s needed.
Bottom line, figure out the cause of the fuel smell, and get it fixed ASAP before it’s a fire hazard.
#7. Engine Surge.
When the fuel injector is spraying too much fuel into the engine cylinder, you will have a surge in the engine. You may even feel the car slightly speed up, then slow down while you’re maintaining a steady throttle position. This is especially noticeable at highway speed.
Engine surging can also present itself as RPM fluctuations under constant load, as you try to maintain a constant RPM.
#8. Poor Fuel Economy.
Similar to fuel injectors that may have failed fuel delivery, they can also deliver excess fuel using the metrics of gas prices today. One of the more obvious signs of this is having to fill your gas tank more than usual.
More specifically, the car’s computer may be trying to account for, lack of fuel, consequently injecting more fuel, worsening your situation. Not only do you feel the impact at the pump, but this excess fuel consumption isn’t particularly great for the environment either.
#9. Failed Emissions Inspection.
This may also be spoken about as it relates to the environment, but due to uneven or incomplete fuel burn due to a faulty fuel injector, associated increased emissions = higher odds of failing an emissions inspection. If you also have a Check Engine light on, failure is even greater odds.
In some examples of fuel injector leaks, the air/fuel mixture can be so rich that it burns out your catalytic converter.
#10. Unequal Cylinder Temperatures.
If you have an infrared thermometer, use this to measure temperatures across your exhaust manifold. Each cylinder should be operating at a similar temperature in a properly running engine.
Should you notice considerable temperature variation between cylinders, then you may have a negative fuel distribution issue, whereby a fuel injector could be a contributing factor.
You’d also want to evaluate your spark plugs, as poorly performing engines can be a contributor to excess heat stress.
Should You Clean Your Fuel Injector?
Some professionals suggest cleaning your car’s injectors every 25,000 to 30,000 miles. While you may think that is excessive, there are huge benefits to cleaning your dirty injectors, especially since it may save you from having to replace one of your injectors.
There are mainly two types of cleaning methods for injectors. The first is the on-car method using equipment that presses a solvent through the injectors, usually while the injectors are still on the car.
There is also an off-car procedure where the technician is able to get the injectors out of the engine and then place them in a machine with dedicated cleaning. Off-car injector cleaning is the best method, but the most expensive.
There are also pre-made bottles of fuel injector cleaner you can buy and pour into your fuel tank. Some professionals swear by them while others feel they are not worth it, and that full-fledged injector cleaning is needed.
Cleaning Cost
Fuel injectors do not last forever, but you can do things to help preserve their lifespan as long as possible. Most experts will recommend you clean the fuel injectors every 30,000 miles or so to avoid the injectors getting clogged and not being able to spray fuel into the cylinder.
Fuel Injector Cleaner
Using a bottle of fuel injector cleaner once in a while is good preventive maintenance and relatively inexpensive. You can expect to pay about $10 to $15 for a bottle of fuel injector cleaner.
For maintenance, you would use one bottle approximately once at your regular oil change, but as often as once each time you fill your gas tank if the injectors are beginning to show symptoms of being clogged.
Professional Fuel Injector Cleaning
For worse cases where the fuel injectors are dirty or clogged enough to prevent proper function, a more expensive professional fuel injector cleaning is required. Expect to pay between $50 and $100 for this service.
Some companies will even allow you to ship dirty fuel injectors, and they will clean them for you for around $15 to $20 each and ship them back (they may do the most detailed cleaning job, expect downtime if you need the injectors on your vehicle).
DIY Fuel Injector Cleaning Kit
As another option, part-time or full-time professional mechanics can buy a fuel injector cleaning kit that will usually pay for itself after so many uses. A good kit will come with several different adapters, which should allow you to work on most fuel-injected vehicles.
When Should You Replace a Damaged Fuel Injector?
Fuel injectors have a lifespan of 50,000 to 100,000 miles in a vehicle, and there have been multiple studies conducted that show fuel injectors may last somewhere in the range of 50,000 to 100,000 miles on average.
There are several indicators to look for when it comes to replacing a fuel injector, such as engine misfire, fuel economy drops, and fuel leaks.
Getting a good fuel injector for your car is essential for getting better performance out of the vehicle.
Using a trained professional is the best way to repair or replace a fuel injector.
How much does a fuel injector replacement cost?
Replacing your fuel injector could get expensive. The costs to replace a fuel injector typically range from $300 to $900, depending on the make and model of your vehicle, the brand of fuel injector, and the location of the repair.
The necessary parts for the fuel injector replacement could run anywhere from $150 to $400.
Being sure to replace your fuel injector properly will help eliminate any issues leading up to the cost of repairs, and also ensure your vehicle is in working condition to operate as efficiently as possible.