Skip to Content

How to Upgrade Fuel Injector on Jeep 4.0? (Cost, Explained)

Your jeep could run OK with standard components. However, if you want more performance, speed, and gas mileage, enhanced injectors is a good option. Such injectors may assist your engine run at peak efficiency and save you money on gas.

Performance injectors increase your vehicle’s power and performance by delivering more fuel into the combustion chamber.

The goal of this post is to throw light on this essential issue by describing when it’s required to change the injectors in your Jeep 4.0 and how to do it correctly.

Can You Upgrade Fuel Injector on Jeep 4.0?

Your Jeep 4.0’s fuel injector can be upgraded. The injection system’s primary responsibility is to start and regulate the combustion process.

Fuel injector improvements are the subject of a lot of misconceptions.

Unlike adding a low restriction air filter, changing fuel injectors is not a “plug-and-play” performance boost.

It’s something that necessitates understanding of how the gasoline distribution system operates.

Before you begin upgrading the fuel injector engine, you must first understand the fundamentals so that you can make the best decision possible.

When Should You Upgrade Fuel Injector?

The fuel injectors won’t be capable of pumping sufficient gasoline to keep the engine from running lean after the engine starts processing more air. This is the time to think about improving your gasoline delivery mechanism. Here are a few indicators.

1. Heat Soak

The injectors are subjected to heat soak when the engine is turned off. The waxy olefins are left behind as the fuel residue evaporates in the injector nozzles.

Because there is no conditioning circulation through the apertures and no fuel running through the injectors to soak it up, the alkynes bake into hard lacquer layers when the engine is turned off.

Detergents are added to gasoline to assist keep the injectors clean because the creation of these deposits is a natural result of engine activity.

However, if your Jeep 4.0 is typically used for short trips, the deposits may accumulate quicker than the detergents can remove them.

2. Less Resistance

When the injector is energized, the solenoid at the top generates a magnetic field that pushes the injector swivel up. Otherwise, the injector may not open all the way because the magnetic field isn’t powerful enough to resist the spring pressure.

Injector solenoid difficulties can also be caused by shorts, openings, or high resistance. When injectors fail, the solenoids frequently short internally resulting in a reduction in resistance.

If a specification requires 3 ohms and an injector only measures 1 ohm, the injector will draw greater energy than the others. If one injector receives too much power, the PCM injector driver circuit may shut down.

3. Balance Test Failure

An injector balancing test can pinpoint a problematic injector if you believe it is blocked or dysfunctional. Injectors can be isolated for diagnostics using scan tools that can deactivate them.

When doing a cylinder balancing test with an injector deactivated, engine rpm decline may not be an appropriate diagnostic procedure. Examining the voltage variations from the O2 sensor is a more effective way.

Even when an injector is deactivated, leaky injectors and certain dead injectors might be overlooked. When an injector is shut off, other faults with the ignition system and mechanical components may not show up as an RPM loss.

4. Failing To Start

Cranking no-start, hard starting, halting, power failure, and poor fuel efficiency are all signs of tainted gasoline. Because the symptoms of gasoline contamination usually manifest soon after refilling, a full fuel gauge needle should always be considered a diagnostic red signal.

Remember to inquire if the jeep has just been refueled, as some drivers simply add fuel to their tanks rather than topping them off.

How Much Does It Cost To Upgrade Fuel Injector On Jeep 4.0?

The cost of replacing your fuel injectors ranges from $250 to $650 on average. The cost range is determined by a variety of things.

Smaller jeeps with fewer cylinders and hence less expensive parts will be at the low end of the price range. Larger, more powerful engines will have a larger price tag. You may also anticipate labor prices to be affected by your location.

Your mechanic will charge you anything from $193 to $415, whereas the Midas shop will cost you anywhere from $206 to $437.

Mr. Tire is comparable in terms of cost, although it is a little more expensive at the higher end of the range, with prices ranging from $215 to $515.

NAPA will provide you with a 24-month guarantee and charge you between $231 and $502 for a fuel injector replacement, but Wal-Mart will charge you between $73 and $264 for only the materials.

My Top Recommendation on Jeep 4.0 Fuel Injector Upgrade

Here are some recommendations for upgrading the fuel injector in your Jeep 4.0.

Remanufactured: 4 Port Upgraded Fuel Injector XJ/MJ

  • They can get greater MPG thanks to an upgraded design that allows for better fuel atomization.
  • For the Bosch or Siemens metal body injectors, the connections are a direct fit, plug, and play replacement.
  • These Fuel Injectors have 4 Hole Discharge Nozzles for greater fuel atomization, quieter idle, improved throttle response, performance, and efficiency.

6X4 Hole Upgrade Fuel Injectors For Jeep 4.0L

  • A high-performance fuel injector that meets the required OEM specifications and is extensively examined before delivery.
  • Enhance your O-ring installation; straight replace your vehicle’s original factory element, made of metal and composite plastic.
  • Internal seal rings in our fuel injectors prevent fuel contamination, reducing in-use “sticking” for longer durability.

High-Performance 6pcs 4-Hole Upgrade Fuel Injectors

  • Manufactured in the front and rear of the vehicle 0280155784 is the part number for this item.
  • Other Item Number: 1999 2000 2001 XJ TJ WJ EV6 4 Nozzle Wrangler Please note that this is a high-quality aftermarket part.
  • Double-checks your replacement parts before purchasing.

How to Upgrade Fuel Injector on Jeep 4.0?

Before you start changing a fuel injector or fuel injection rail, you should consider your safety. When working with gasoline, always keep fire safety in mind. Make sure you’re using eye protection as well.

This is a step-by-step guide on how to upgrade the fuel injector on your Jeep 4.0:

1. Starting

Make sure you follow the technique for releasing the pressure in the fuel system. This is a critical point.

Examine the injection system of your vehicle. Some systems are easy to find, while others are nearly hidden. Plan your attack so that your work is well-organized.

If you’re going to remove fuel injectors, you should acquire a fuel injector puller. There are alternative options, but you run the risk of harming costly fuel injection components.

2. Fuel Rail Disconnection

If your fuel injection system uses a fuel rail to feed gasoline to the injectors, you must first remove the fuel rail before removing the injectors. This is a simple task.

To begin, disconnect the primary fuel line at the rail’s end. There might be another line at the other end, so delete that as well. Depending on your car’s arrangement, screws or bolts hold the fuel rail in place.

These screws or bolts must be removed. If your wiring crosses the top of the rail, go to the following step to disconnect it. Pull the rail away from the fuel injectors with everything detached from it.

3. Fuel Injector Disconnection

You removed the fuel rail in the previous step if your vehicle requires one to feed fuel to the injectors. You’ll need to remove a fuel line from the top of each injector if you don’t have a fuel rail. It’s just as simple to take out; just be careful.

You can now unplug the fuel injectors when the fuel supply has been completed. Each injector will have a connector that connects to the wire harness at the top.

A springy wire holds most fuel injector wiring connectors securely in place. Simply place a flat head screwdriver in the gap between the spring and the plug and gradually push the wire-free. It’ll be simple to remove. Don’t let it go.

4. Fuel Injector Pulling

You’re ready to remove the injector now that everything else is out of the way. Many individuals, unfortunately, attempt to pull them out. Understand that your fuel injectors are directly in the midst of the engine’s most fragile area.

A fuel injector puller is the safest technique to remove a fuel injector. There are various ways to remove gasoline injectors, but you risk damaging certain valuable fuel injection components if you aren’t cautious.

Furthermore, the injector puller makes it simple to remove the injector; simply slip it beneath the lip in the injector housing and pull the injector out.


Installation, as every vehicle repair instruction will tell you, is the inverse of removal. Before installing the new injector seals, make sure they’re lubricated and that you don’t pressure something in. Fuel injection techniques have been developed to the point that they usually last a long period with little maintenance. However, this does not imply that they will last indefinitely.

Related Posts:

Leave a comment

Your email address will not be published. Required fields are marked *