how to rebuild lb7 injectors

How to Rebuild LB7 Injectors, the Ultimate Guide

If you’re the type who wants to take the hands-on approach of repairing your LB7 DURAMAX injectors then we can help you out. This is a guide on getting to know your LB7 injectors and how to rebuild LB7 injectors on your own. LB7 injectors are sometimes unstable and usually truck owners need to replace these more often than injectors of other trucks.


What causes LB7 injector problems?

DURAMAX LB7 trucks are known for their great performance and efficiency, however a great number of truck owners are not too happy about early LB7 injector failure. According to most truck owners, LB7 injector failures happen because of the following reasons:

  • Contamination of the fuel system

Poor engine maintenance will affect your fuel system as the system can become contaminated with water, contaminants, and dust. The fuel system can become coated with grime and this makes it more susceptible to erosion. Once the different components of the system have eroded, the fuel injector will soon fail. 

  • Poor lubrication

Poor lubrication leads to the wear and tear of the fuel injectors and this will eventually lead to failure.

  • Over-torqued system

Over-torqued fuel injection parts can lead to leaks and this could be dangerous. Leaking fuel can move to the crankcase and will lead to other problems.

  • Issues of old fuel injectors

Old fuel injector components have many issues. The fuel injectors that were manufactured in 2007 have flaws that make these fail quicker. The design of the ball seat to cover the injector is not solid and thus, daily pressure can lead to early erosion.


How to tell if your LB7 Injector needs repair/rebuilding?

Now that you know what causes LB7 injector failure, you must also get to know some of the ways to tell if your injectors are close to failure. Here are some of the most efficient LB7 injector testing techniques.

  • Have your balance rates checked

Check your fuel injectors' balance rate. This is done electronically and is reflected from your onboard display. If this is higher than 3 square millimeters then your LB7 injector has failed.

  • Check the crankcase

Find out if your crankcase has fuel. If you find fuel on this component then there may be leaks in the fuel injector. You should never overlook any leaks.

  • Check any unburned fuel smell

Smell your vehicle and check for any unburned fuel smell. This unusual smell means that your injector system may be failing. It is dangerous to have leaking fuel as much as this can affect your fuel economy. You must take your car to a repair shop for maintenance ASAP.


Steps how to rebuild LB7 injectors

We recommend leaving repairs and rebuilds like an LB7 injector rebuild to be left to professionals. But if you want to learn how to proceed at your own risk. Having basic knowledge about engine repair and maintenance can help you so much when you want to rebuild diesel injectors on your own.

Take the fuel injector system apart

Take the fuel injector apart. This component comes in three parts: the body, the nozzle, and the cap. Inside the fuel injector body is a spring and this needs to be turned to open the component. Once the nozzle is removed from the injector, take the spring out.

Take a photo of what the fuel injector looks like when assembled and other images of the component in different stages of disassembly. These can help you rebuild the LB7 fuel injectors after you have cleaned and replaced its parts.

Remove grime, dirt, and dust

Diesel injectors are very prone to the accumulation of grease, dust, and grime and this amount of dirt is worse when your injectors have not been cleaned or maintained for a long time.

You must clean these using some alcohol and a small soft brush. Dip the dirty part in alcohol for a short time and then use the brush to remove all the dirt.

If you have pressurized air, you can use this to clean all injector parts very well. Afterward, use paper towels to wipe everything.

Rebuild the fuel injector with new components

Replace the injector’s old nozzle and the cap with new ones. When you’re done, take the different parts and re-assemble the injector. Tighten the injector cap with a wrench.

You may use the photos of the LB7 Duramax injector components as a guide to avoiding any errors upon re-assembly.

Rebuilding injectors in my LB7 Duramax YouTube Video


Is it really better to rebuild an LB7 DURAMAX injector?

A lot of LB7 Duramax truck owners say that an LB7 DURAMAX injector rebuild is not practical as you are likely to spend a lot of time taking things down, cleaning, replacing, and re-assembling. It's easier to order new injectors and replace the old failing ones. Also, consider that if you're not familiar with fixing injectors or you are rebuilding one in an uncontrolled setting then contaminants may still affect the system. You may still end up rebuilding and cleaning the injectors soon.

But if you’re the kind who finds value in learning different technical tasks, then this is an invaluable learning opportunity for you.


How to keep your fuel injectors healthy?

To save yourself time, money, and effort in rebuilding LB7 fuel injectors, follow these preventive tips:

  • Always keep the fuel system neat and clean

A clean system will reduce grime and dust that build up inside the injectors.

  • Use only clean and high-quality fuel

Dirty, low-quality fuels will end up damaging the injectors and affect their function.

  • Consider fuel injector cleaners

Buy quality fuel injector cleaners. These are usually added to regular fuel to improve engine function. These products will enhance the function of your LB7 fuel injectors.

  • Refuel only from a reliable source

Refuel from a good, quality fuel station. If you need to travel remotely,  go on a full tank, or have a fuel container filled with your preferred quality fuel.


Now that you know how to rebuild LB7 injectors, you'll be saving money on professional mechanic fees and parts. Indeed this is a learning opportunity and a great way to revive an ailing fuel injector. Have fun rebuilding your LB7 DURAMAX injectors.

About the Author JamesL Davis

James is a certified auto technician specializing in commercial vehicles. With 30 years of experience under his belt, James has encountered almost every type of automotive issue there is! Besides his day job at the repair shop, he is also an amateur race car driver.

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