Picture this: your truck is in bad shape. It’s rough idling, guzzling fuel faster than usual, jerking at stops, and has been all over the place in terms of revolutions per minute (RPM). Your truck is displaying dirty fuel injector symptoms.
But what exactly is a fuel injector? And, how do you know when it’s dirty, gone bad, or needs fixing?
Understanding the symptoms of faulty fuel injectors can help you diagnose your rig’s suspicious behavior, so you can get back to doing what you do best.
If you’re looking for clear signs and indicators that signify a dirty or faulty fuel injector, you’ve come to the right place.
In this quick read, we’ll discuss:
- The functions of fuel injectors
- What causes dirty fuel injectors to fail
- 7 tell-tale symptoms of bad fuel injectors
- How to prevent dirty fuel injectors from causing damage to a vehicle
- Tips for fixing faulty or dirty fuel injectors
Table: The 7 bad fuel injector symptoms
| 1. A vehicle’s engine misfires. 2. A vehicle rough idles. 3. Fuel mileage decreases. 4. The revolutions per minute (RPM) needle starts acting up. 5. The check-engine light turns on. 6. The vehicle refuses to turn on. 7. Fuel leaks pop up. |
But first, what does a fuel injector do?
If you’re new to fuel injectors, we’re here to help. Your fuel system includes a fuel filter, pump, and injectors that are interconnected under the hood of your truck. The filter, pump, and injectors ensure your engine receives the right mix of air and fuel, so that your truck can keep on cruising.
Here’s how the fuel system works on a vehicle in four simple steps:
- Step 1: Your truck’s fuel pump pumps fuel to the fuel injectors
- Step 2: Your fuel injectors go to work. They inject fuel via a fine mist into the intake manifold.
- Step 3: Air and fuel meet inside the combustion chamber and intake manifold.
- Step 4: As the air and fuel mix, the mixture compresses in the combustion chamber.
If a fuel injector isn’t working, don’t hesitate or neglect to act. Issues with the combustion process can occur, which can lead to increased emissions, exhaust, and buildup of harmful substances in the engine.
By understanding how a fuel injector works in diesel engines, you can diagnose fuel injector issues before they affect engine performance or become significant liabilities.
What causes a fuel injector to fail?
Speaking of performance and fuel, how exactly does a fuel injector fail? Here are some of the most common reasons for a fuel injector failing.
- The fuel injector becomes contaminated and clogged: Dirt, carbon, and poor-quality fuel can clog up your system, reduce fuel flow, and cause misfires.
- The fuel injector experiences electrical issues: Wiring issues can affect the injector from opening. The result is a defective fuel injector that could hurt an engine’s performance.
- Fuel system failures: Sometimes, the issue isn’t as much the fuel injector as it is other components in the fuel system. Fuel pumps, pressure regulators, and vacuum leaks can affect how the fuel moves through the system. As a result, the fuel injection system might appear to be malfunctioning when the culprit is really the fuel system.
- Incompatible fuel: Using the wrong fuel, or contaminated fuel in general, can prevent fuel injectors from working and can cause injector problems and combustion issues.
The good news is that familiarizing yourself with the symptoms of a bad fuel injector can help you prevent fuel injector issues from popping up in the first place. Let’s take a look at some of the most common signs and symptoms of failed fuel injectors.
The 7 symptoms of failed fuel injectors
To help diagnose malfunctioning fuel injectors, you’ll want to know what happens when dirty fuel injectors go bad. Here are some of the most common symptoms of dirty and failed fuel injectors.
1. Engine misfires
A failed fuel injector starts with a dirty fuel injector. And, a dirty fuel injector can cause a vehicle’s engine to misfire.
How do you know if your engine is misfiring? If you notice that your vehicle is spluttering or vibrating, you could be experiencing an engine misfire.
In other words, a misfire can occur when the fuel injector affects the mix of air and fuel inside the engine. The disequilibrium created by the imbalance can affect the vehicle’s performance.
To determine a dirty or faulty injector, check your engine first.
2. The vehicle experiences rough idling
Rough idling refers to when your vehicle experiences variable revolutions per minute (RPM) even when your foot is off the gas pedal. Occasionally, you’ll also notice that rough idling is accompanied by an engine stalling.
In general, rough idling and engine stalls can also indicate symptoms of a larger problem. You could be experiencing issues with your engine.
Also, if you notice your truck is shaking while at a standstill, the shaking could be a sign of dirty fuel injectors.
If you notice issues under the hood of your vehicle, we recommend coming in for an in-shop truck repair and engine diagnostic service. A professional diesel truck technician can conduct a comprehensive, multi-point fuel system inspection and provide fuel system cleaning if needed.
3. Fuel mileage decreases
When your engine runs smoothly and efficiently, your truck can keep you going for miles and miles. Often, as is the case, dirty fuel injectors can cause poor fuel economy.
Reduced fuel efficiency and fuel mileage are another unfortunate side effect and symptom that a pair of eyes are needed on the fuel injectors.
4. The tachometer/ RPM needle goes haywire
You might like to think you’re in control of your vehicle at all times. Not so when you have a dirty fuel injector under the hood of your vehicle.
Dirty fuel injectors can cause the needle on the tachometer gauge to move in an erratic fashion. If you notice that the needle moves in unpredictable ways, even if you’re not changing gears in your vehicle, you could be experiencing issues with your fuel injectors.
5. Check engine light turns on
The classic check engine light: if it turns on in your dashboard, you might be experiencing issues with your fuel injectors. For example, when an injector delivers an inconsistent amount of fuel, the result can be decreased engine performance and poorer fuel economy.
What’s more, if the right amount of fuel isn’t entering the engine’s combustion chamber, you could experience issues with the engine.
6. Your vehicle won’t turn on
Also, if the right amount of fuel isn’t entering the engine’s combustion chamber, you could experience issues with the engine. Too much or too little fuel in your engine can cause issues with the fuel injectors and other engine components.
Fuel injectors provide gas to the cylinders in the vehicle. If they don’t, your engine won’t receive the right air and fuel mixture it needs to operate.
If the air and fuel mixture is off, your vehicle’s motor won’t be able to generate the combustion needed to keep it moving. Sometimes, fuel injectors can even prevent fuel from entering your engine, which can result in the vehicle not starting
That’s why proper preventive maintenance is key. By bringing your truck in for regular maintenance, you can prevent issues before they lead to vehicle failures.
7. A fuel leak (or clog) occurs in the fuel system
Without proper preventive maintenance, leaks can occur, especially in fuel injectors. The reason is that fuel injectors experience a ton of wear and tear.
The heat and moisture that build up inside it can lead to cracks. The cracks then lead to leaks in the rubber seals in the fuel injectors, and the result is reduced engine performance and potential earnings.
How do you prevent dirty fuel injectors from causing damage?
Fuel injector issues can lead to serious damage. Fortunately, when you take proactive steps to fix them, you can protect the life of your vehicle and keep your engine running in peak condition.
Here are some steps you can take to prevent fuel injector failures:
- Drive your vehicle often: when old fuel sits in a vehicle that hasn’t been driven for a long period of time, the fuel can build up and cause issues if not used.
- Fill your fuel tank up before it runs low: when you run your truck near the empty sign, sediment can build up, which can lead to clogged injectors.
- Change your fuel filter per your manufacturer’s recommendations: Doing so helps prevent contamination in the fuel tank and fuel injectors.
- Drive with the right fuel in your fuel tank: This may sound obvious, but it’s worth mentioning. Poor-quality or incompatible fuel can leave deposits at the bottom of the fuel tank. Always make sure to use high-quality fuel in your tank to help prevent fuel injector issues.
- Schedule maintenance or a phone call with a professional truck consultant: a certified truck advisory technician can show you how to operate your vehicle so it maximizes fuel efficiency and prevents engine- and fuel-related issues from arising.
Tips for fixing faulty fuel injectors
Wondering how to diagnose a faulty fuel injector? Identifying a bad injector isn’t always as simple as it seems. Many of the symptoms of a faulty injector may also point to other engine issues, such as a failing manifold gasket.
We recommend speaking to a diesel truck mechanic who has the tools, equipment, and experience to help fix the problem pronto, the first time around.
If you think your fuel injectors need a little attention and you live on Long Island, NY, we invite you to visit our shop. We’ll conduct a complete vehicle inspection and fix any issues that can affect your ride.
Don’t live on Long Island, NY, but still want a professional mechanic’s advice? Don’t sweat it.
Our diesel technicians would be happy to answer any questions you have. Whether you’re looking for tips on how to prepare and pass roadside inspections, doing your own DOT inspection, or reducing vehicle emissions, we have your back, and we’d be happy to help.
To get in touch with our knowledgeable and dedicated diesel truck technicians, contact us today.
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