Does your vehicle have poor performance, lousy gas mileage, or rough idling? It either has a severe case of the Mondays or, more likely, some dirty fuel injectors.
Spotting the signs of dirty fuel injectors and investing in a quick cleaning can help you smooth out your rough ride and get back to carefree cruising.
What Is A Fuel Injector?
The fuel injector is a critical component of the modern automobile, responsible for atomizing and injecting fuel into the combustion chamber. A fuel injector is considered the “heart” of the engine.
The fuel injector, connected to an Electronic Control Unit (ECU), regulates the fuel injection process. The ECU controls the opening and closing of the solenoid valve to inject the fuel in the high-pressure fuel rail into the combustion chamber to ensure efficient combustion.
The fuel injector injects atomized fuel directly into the engine’s combustion chamber. This process of delivering fuel to the engine is known as fuel injection.
The fuel injection process helps to provide maximum power while minimizing fuel consumption and reducing pollution. Fuel injectors help reduce emissions by producing a finer fuel droplet spray that burns more efficiently.
Electronic fuel injectors are more reliable and efficient than the ones used in the past, making them a popular choice.
How Does The Fuel Injector Work?
A fuel injector comprises a solenoid, a nozzle, and an injector body. The fuel injector nozzle is a precision-machined device with two openings: an inlet and an outlet. As the inlet draws fuel from the fuel tank, the outlet sprays fuel into the combustion chamber.
The fuel injection process helps ensure that fuel is delivered most efficiently. Fuel injectors are typically made of stainless steel and have a plunger or valve that opens and closes to control fuel flow.
The injector body is responsible for converting the electrical signal from the solenoid into pressure to push the fuel through the nozzle. When the injector is triggered, the solenoid opens, allowing the fuel to flow through the nozzle and into the engine’s combustion chamber.
The fuel injectors, connected to the fuel rail, carry fuel from the fuel tank to the injectors. The fuel injectors read data from sensors to determine how much fuel needs to be injected into the engine.
Bad Fuel Injector Symptoms
Here are some of the most common signs of a fuel injector issue. Keep in mind that the fuel injector in question may simply be clogged so don’t automatically think that replacement is necessary.
Using a bottle of fuel injector cleaner may help, and even better, doing a proper cleaning with a fuel injector cleaning kit is recommended before spending the money on new injectors.
#1. Rough Idle or Engine Stalls.
Because your vehicle is not getting enough fuel or an uneven supply of fuel, the RPM while idling drops below the optimal level and results in a rough or even violent idle. If the RPM falls too low, the car may actually stall and you will need to restart.
This issue is particularly noticeable when your engine is cold or when you’re sitting at a stoplight.
#2. Engine Vibrates.
Bad fuel injectors can prevent specific cylinders from firing properly, resulting in noticeable engine vibrations. As you drive, you may feel a rhythmic shaking (through the seat or steering wheel) or hiccupping sensation, especially when maintaining a steady speed.
This happens because the affected cylinder isn’t receiving the correct amount of fuel, disrupting the engine’s normal firing sequence.
The vibration can vary in intensity depending on which injector is malfunctioning and how severely it’s affected. You might also notice the vibration is more pronounced at certain RPM ranges.
#3. Engine Misfires.
Engine misfires happen when a cylinder doesn’t fire correctly, often due to a clogged or malfunctioning fuel injector. You’ll likely notice a hesitation or stumble when accelerating, almost as if the engine is briefly losing power. In some cases, you might feel a slight jerk or shudder.
While fuel injectors aren’t the only cause of misfires, they’re a common culprit and should be one of the first things checked when this symptom occurs. Any time an engine’s air/fuel ratio is upset, you’ll want to resolve it quickly.
#4. Check Engine Light Turns On.
The most obvious sign of any car problem is when the “Check Engine” light illuminates on your dashboard. Although this could mean a lot of things, a bad fuel injector (indicated by a code such as P0201, P0202, P0203, or P0204) could be one of them.
Any time an injector delivers less fuel than needed (or more in some cases), the engines efficiency is lowered and can trigger the CEL to come on. Use an OBD2 scanner to confirm the issue.
#5. Fuel Leak
If your fuel injector is actually broken or cracked from damage or old age, then fuel will begin to leak out of it. You may notice wetness around the fuel rail area, and in severe cases, actual gasoline pooling on the ground underneath.
In most cases, the leak originates from a deteriorated fuel injector seal. But no matter the severity of the leak, you’re dealing with fuel, making it a significant fire hazard. Get it fixed ASAP.
#6. Fuel Odor.
This goes along with a fuel leak but when you have gasoline that’s not getting burned due to a damaged injector or one that’s stuck open, you’re going to smell gasoline. Sometimes the issue may be your fuel lines or a faulty sensor telling the ECU to inject more fuel than in necessary.
Either way, you need to find the cause of the fuel odor and fix it right away before it becomes a major fire hazard.
#7. Engine Surge.
If the fuel injector is spraying too much fuel into the engine cylinder, this will create a surge in the engine. You might feel the car speeding up and slowing down slightly while maintaining a steady throttle position. This uneven performance is particularly noticeable during highway driving.
Engine surging can also present itself as RPM fluctuations under constant load, rather than remaining at a constant RPM.
#8. Bad Fuel Economy.
Similar to how a bad fuel injector may not deliver enough fuel, it may be delivering more fuel than necessary. One of the most obvious signs of this is having to fill up your gas tank more often than usual.
Your car’s computer might try to compensate for perceived fuel shortages by injecting even more fuel, further worsening the situation. This excess fuel consumption not only hits your wallet at the pump but it’s not exactly good for the environment.
#9. Failed Emissions Test.
And speaking of the environment, because a faulty fuel injector can cause an uneven or incomplete fuel burn, increased emissions are a result. This means your chances of failing an emissions inspection increase greatly. If you’re also getting a Check Engine light, failure is guaranteed.
In some cases, a fuel injector leak can cause the air/fuel mixture to be so rich that it eventually burns out the catalytic converter.
#10. Uneven Cylinder Temperatures.
If you have access to an infrared thermometer, you can use it to measure temps across your exhaust manifold. Each cylinder should have a similar temperature when your engine is running properly.
If you notice signification temperature variations between cylinders, you may be dealing with uneven fuel distribution, with a fuel injector being a possible cause. Poor engine performance often comes along with it. That said, you’ll want to take a look at your spark plugs as well.
Should You Clean Your Fuel Injectors?
Some experts recommend cleaning your car’s injectors every 25,000 to 30,000 miles. Although some might say that’s overkill, there are definite benefits to cleaning dirty fuel injectors, one of which is that it may save you from having to replace one or more of the injectors.
There are two primary injector cleaning methods. The first is the on-car method, which typically involves using pressurized equipment to run solvent through the injectors.
There’s also an off-car procedure, where the technician removes the injectors from the engine, then places them in a dedicated cleaning machine. Cleaning the injectors off of the car provides the best results, but it’s also the most expensive of the two methods.
Also, there are bottles of fuel injector cleaner that you can pour into your gas tank. Some professionals swear by these products, while others feel they don’t do enough on their own without a full-fledged injector cleaning.
Cleaning Cost
Fuel injectors do not last forever but you can take steps in preserving their lifespan for as long as possible. Many experts recommend that the fuel injectors be cleaned every 30,000 miles or so. That way, the injectors don’t get clogged and prevent fuel from spraying into the cylinder.
Fuel Injector Cleaner
Using a bottle of fuel injector cleaner every now is good preventive maintenance and it’s fairly cheap. Expect to pay about $10-$15 for a bottle of cleaner.
For maintenance, you’d use one bottle right around the time you do a regular oil change but as often as every time you fill your gas tank if the injectors are already showing signs of being clogged.
Professional Fuel Injector Cleaning
For more severe cases of dirty or clogged injectors, a more expensive professional cleaning is required. Expect to pay anywhere from $50-$100 for this service.
Some companies even allow you to ship them your dirty injectors where they’ll clean them for around $15-$20 each and then ship them back. They’ll probably do the most thorough job but you’ll obviously have some down time if you need your vehicle.
DIY Fuel Injector Cleaning Kit
Alternatively, part-time or full-time professional mechanics can purchase a fuel injector cleaning kit that will usually pay for itself after a few uses. A good kit will include various adapters to allow you to work on most fuel injected vehicles.
When To Replace A Malfunctioning Fuel Injector
The fuel injectors in a car will typically last between 50,000 and 100,000 miles, but according to numerous studies, the components will last anywhere from 50k to 100k miles.
Several warning signs can indicate that the fuel injector needs to be replaced, such as engine misfires, reduced fuel efficiency, and fuel leaks. Getting a quality fuel injector back on the car is crucial to improve the vehicle’s performance.
Hiring a professional is the best way to ensure a suitable fuel injector replacement.
How Much Does It Cost To Replace A Fuel Injector?
Replacing a fuel injector can be costly and ranges from $300 to $900, depending on the type of vehicle, the fuel injector’s brand, and the repair’s location. The cost of the parts and labor for the replacement can range from $150 to $400.
It is essential to replace the fuel injector adequately to avoid problems down the road and ensure that the car runs efficiently.