Diesel Injector Buyer’s Guide
- Mechanisms like carburetors and fuel injectors are what help combine fuel with air into the proper ratio for the engine to burn.
- While carburetors rely on pressure difference to draw fuel that will mix with the air flowing to the engine, fuel injectors are designed to infuse the air with fuel.
- A diesel injector is specifically made for diesel engines, which is a type of compression-ignition engine.
- The types of fuel injectors include single-point or throttle body injectors, multipoint port fuel injectors, and direct fuel injectors. A diesel injector is a type of direct fuel injector.
- Fuel injectors, including diesel fuel injectors, are structured similarly to retractable pens with the inner needle serving as a valve that can be moved mechanically by pressure or electronically by the car’s computer.
- When the needle is moved inwards, fuel can come out from the opening in the nozzle.
- How to tell if a diesel injector is bad is by observing the engine’s performance, since it is the injector that is responsible for supplying fuel into the engine. Other bad diesel injector symptoms include diesel odors, poor emissions, and reduced gas mileage.
- Aftermarket diesel fuel injectors can cost from around $52 to $334.
- Aside from the fit and the cost, you should also consider the material used to make the diesel fuel injector. It should be durable enough to withstand being under a lot of pressure.
In cars with internal-combustion engines, power is generated by the movement of the pistons, which in turn rotate the crankshaft to produce torque. This rotation is then translated and transferred to the wheels to make the car move. Force is needed for the pistons to move. Without any mechanical part to move the pistons, what provides the required force is the explosion from the combustion of fuel.
To make engines produce as much power as possible, engineers made combustion more efficient by designing ways to better mix fuel with oxygen. Mechanisms like carburetors and fuel injectors are what help combine fuel with air into the proper ratio for the engine to burn. While carburetors rely on pressure difference to draw fuel that will mix with the air flowing to the engine, fuel injectors are designed to infuse the air with fuel.
What is A Diesel Injector?
The type of fuel injector in a vehicle will depend on the engine it has. A diesel injector is specifically made for diesel engines, which is a type of compression-ignition engine. Unlike in gasoline engines that use sparks to ignite the air-fuel mixture, diesel engines are usually designed to make the air in the cylinder hot enough to burn the fuel.
A fuel injector is basically the output nozzle of the fuel delivery system. It is mainly classified by its location.
Single-Point or Throttle Body Injector
Located before the intake manifold, the throttle body houses a valve that helps control the amount of air that goes into the engine. The fuel injector in the throttle body adds fuel to the air that goes through the throttle body and into the intake manifold.
Multipoint Port Fuel Injector
The intake valve is what lets air in from the intake manifold to the engine cylinder during the intake stroke. With a multipoint port fuel injector (MPFI), the fuel is sprayed at the intake valve during the intake stroke. Due to how it functions, each cylinder will have one MPFI. The version of this fuel injector that features a timing system is called a sequential fuel injector.
Direct Fuel Injector
Fuel is delivered right into the engine cylinder with a direct fuel injector. The nozzle of this injector has access to the inside of the cylinder.
Since diesel engines ignite the fuel using the air that is heated in the engine cylinder, the fuel would have to be added during the compression stroke when the air is under high pressure. To do this, diesel engines make use of direct fuel injection. This means that a diesel fuel injector is usually a type of direct fuel injector.
How Does a Diesel Fuel Injector Work?
Fuel injectors, including diesel fuel injectors, are structured similarly to retractable pens in that they have a hollow body encasing a spring and a moving inner component. Inside the hollow injector body is the injector needle which serves as a valve. A spring pushes the needle towards the tapered end, keeping the nozzle hole blocked.
In the simplest type of fuel injector, such as a mechanical diesel injector, the needle and inner part of the body are shaped in a way that fuel can get to the shoulders of the needle. When there is enough pressure, the fuel can push back on the needle and flow through the opening that is created. As for more modern fuel injectors, the actuation of the needle is controlled by the car’s computer.
Since it has to release fuel into the compressed air, the fuel injector in a diesel engine should be able to produce a hard spray that can penetrate the pressurized air. The design of the injector nozzle helps with how the fuel is sprayed into the cylinder. Usually, the hole injector nozzle type is what enables hard sprays while the pintle type is able to spray fuel at lower pressures.
Bad Injector Symptoms in Diesel Engines
Due to all the different types of pressure that a diesel engine injector has to handle, it could wear, crack, or break over time. You can tell a diesel injector is bad by observing the engine’s performance, since it is the injector that is responsible for supplying fuel into the engine. Other bad diesel injector symptoms include the following:
When fuel for combustion cannot be delivered properly, the engine might vibrate or hiccup, misfire, or stall. You might also experience longer cranking or starting times and rough idling.
Fuel might leak out instead of going into the cylinder when the diesel injector has cracks. When this happens, you might smell the diesel fuel that is leaking out of the injector.
The engine might not be able to burn the fuel properly due to having the wrong air to fuel ratio (AFR). This could make the exhaust appear dark or black.
Reduced Gas Mileage
Since the engine is not receiving the right amount of fuel it needs to burn, the fuel delivery system and your car’s computer might signal for more fuel to be sent to the engine. This would increase consumption and lessen fuel economy.
If you see or experience any or all of these diesel injector problems and symptoms, it would be best to bring your vehicle to a certified and experienced mechanic. It is possible that the signs are caused by another component of the fuel delivery system or by a part of the engine. Your mechanic would have the right tools needed to pinpoint exactly where the problem is. Replacing a diesel injector could get expensive, so isolating and identifying only the bad injectors instead of replacing all of them would be ideal.
Diesel Fuel Injector Replacement
It is important to have a worn diesel injector replaced immediately to avoid further complications and potentially more expensive repairs. How much a diesel injector is would depend on the type that would fit your vehicle’s make, model, and year. Aftermarket diesel fuel injectors can cost from around $52 to $334. Aside from the fit and the cost, you should also consider the material used to make the diesel fuel injector. It should be durable enough to withstand being under a lot of pressure.
Dos and Don'ts when Buying a Diesel Injector
Do not neglect the signs of a damaged diesel injector. When you are experiencing difficult car start ups, severe fuel leaks in the cylinders, and too much smoke from the exhaust, you have to act quickly and do the necessary repair procedure. The first step in fixing this problem is finding a replacement diesel injector. The task may be a little tricky if it's your first time to do this. To help you out, you can refer to the following tips on what you should do and what you should avoid when buying a diesel injector.
- Determine the right amount of flow rate that your vehicle requires to achieve its maximum efficiency. Flow rate is the amount of fluid that passes through the cylinders at a given unit of time. Diesel injectors come in different levels of flow rate, which are predetermined by the manufacturer. You have to bear in mind that the increase in horsepower and speed depends on the flow of fuel that the diesel injector can possibly allow.
- Choose a diesel injector that is made from the finest materials and components to be sure that it can last for a long time. The temperature inside the combustion engine can be extremely hot. Only prime metal types such as iron and steel can withstand that condition. That's why when buying, you have to watch out for the kind of metal used in producing the injector.
- When selecting a diesel injector, take in consideration the design of the injector's nozzle. It may not be obvious, but size and form of the nozzle and its needle affects the fuel flow rate. When looking for injectors online, carefully check the catalogues for information regarding the nozzle type.
- Do not buy from unauthorized dealers or resellers. It's highly advisable to buy from only trusted brands to be sure that you're not only getting a high quality injector, but also a product warranty. Diesel injectors are pricey; they cost a hundred dollars or more. Branded injectors have a heftier price tag, but you have to remember that you're also paying for the warranty, and this warranty is your protection in case you bought a wrong part or you got a damaged injector.
- Do not purchase a diesel injector unless it's an OE replacement or a direct fit. Remember that leaking fuel in the cylinders is a very common problem when the injector loosened and lost its proper fit in the cylinder. A wrong-sized replacement injector, even though it's new, may generate the same problem. Aside from fuel leaks, you'll also have a hard time installing it because you still have to cut or trim it.
Amp Up That Horsepower: Install a Diesel Injector
One of the simplest and easiest performance enhancements that you can do to maximize your car's fuel-efficiency and horsepower is by installing a diesel injector. The diesel injector pumps the highly pressurized fuel into the cylinders for efficient distribution into the combustion chambers. It helps a lot in burning the fuel well to generate more power and speed.
Installing diesel injectors in your car may only take a few minutes. If you're ready to amp up your car's performance, here is what you have to do.
Difficulty level: Moderate
Prepare these tools:
- Safety glasses
Step 1: Open the car's hood and locate the valve cover. It is usually on top of the engine. Remove that cover by using the ratchet and the socket to unfasten the two bolts that hold it.
Step 2: Find the fuel injectors. Use a clean rag to wipe off dirt from the injectors and the fuel lines.
Step 3: Locate the fuel supply lines. A line, usually in gold color, is attached to each of the injector. Remove that using your wrench.
Step 4: Take out the two bolts that hold the injector holder. Take it out of the engine for a while.
Step 5: Pull the injector out of the engine. Don't forget to wear your safety glasses because some of the fuel may squirt. Pull the entire injector assembly including the washer. Place a small duct tape on the open valve to prevent dirt from getting in.
Step 6: Place the new injector. Put back the injector holder and tighten the bolts. Repeat the same procedure for the remaining injectors.
Step 7: Reattach the fuel lines and make sure that all bolts are back in place.
Step 8: Return the valve cover. Test the car after to see if there's any leak.
See the difference that one part can make in the overall function of your car. Enjoy the DIY project and good luck!