article do i replace a single fuel injector or the entire set
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Can You Replace One Fuel Injector Or The Full Set? Read This!

When dealing with a faulty or an old diesel fuel injector that needs replacement, a common question that comes up is whether one should replace the one faulty injector in your engine, or the entire set of diesel fuel injectors? 

We’ve talked a lot about the role of diesel fuel injectors in your engine, along with signs to look for if you suspect that you’re having problems with your injectors. Now let’s dive into certain factors to consider if you need to replace one of the injectors that go into your Doosan Bobcat engine, used in excavators, skid steers, track loaders, tool cat machines, skid steer loader and tow compressors. Although we will be talking about replacing bad injectors related to the D18, D24 and D34 engines, these tips can help you with any diesel fuel injector. 

Before jumping into factors to consider, if you are personally inspecting the injectors to determine whether there is an issue, be sure to only remove the faulty injector from the engine. If you need to remove all of the injectors from the engine, make sure to label each one to prevent forgetting in which order they were originally placed since each injector needs to be coded with an ECU. 

Tip #1: What Condition is Each Injector in? The Others May Not Have Much Time Left.

Let’s say your check engine light turns on and you find that one of your fuel injectors is no longer working. Have you conducted a leak test? Have you done cleaning on the other injectors? Are there early signs of potential issues that may arise in your other injectors? Do these injectors have 50,000+ miles on them already? If you answered yes, to any of these questions, then we recommend replacing all four of your fuel injectors. The reason why is that there may be a short while left before another one of your injectors gives out and starts having issues. Replacing one or four injectors is a process that costs you time and money, so its usually better to change all injectors at once while your machine is down. 

Furthermore, cleaning injectors is highly recommended from a regular maintenance perspective, but it will not undo the wear and tear that comes naturally from use over time. 

If you are not the one who is inspecting these injectors, we recommend taking all four injectors into a dealer who can provide you with a test on the quality of each injector and proceed from there. 

On the other hand, if your fuel injectors are still fairly new and perhaps you have an issue with one fuel injector due to a manufacturer's defect, then its a safer call to replace that one faulty injector. 

Tip #2: What Caused The Problem? 

Hitting on our last point, do you know what caused the failed injector to malfunction? What symptoms did your machine or injector show? Did it malfunction due to old age and the general wear and tear that all fuel injectors eventually get? It’s important to get down to the bottom of what caused this fuel injector to fail. There may be a more serious underlying issue with your entire fuel system overhaul kit or engine, such as your fuel pressure controller, wiring issues or the driver subsystem. If its a more serious issue, replacing the injectors will not be the entire solution. 

Tip #3: How Fast Do You Need to Get Your Engine Back Up and Running? If Its Urgent, Skip Testing Your Injectors From a Dealer. 

We know that many folks only have one or two machines they rely on and use everyday. For many, a down machine means a loss in money, so if you need your machine repaired as soon as possible, then we recommend purchasing an entire new set. Sending them off to a dealer to get your fuel injectors checked has many benefits, but not necessarily on saving time. 

Tip #4: Will You Or a Mechanic Replace the Injector? Cost of Labor and Time Adds Up. 

This is another important factor to consider. Say your fuel injectors are fairly new and have not given you issues before. It just so happens that one out of the four injectors really is faulty. If you personally plan on replacing that one faulty injector at home, then it may make most sense to only replace one of them. We highly advise you to be experienced and familiar with replacing parts otherwise you cause more issues by damaging another part in your fuel system. If you’re familiar with replacements, then it should be a simple fix for you, and you may not have to replace the entire set. 

On the other hand, if you plan on taking this to a mechanic for replacement, then we suggest replacing the whole set of fuel injectors as mechanics are expensive when it comes to cost of labor and replacement. Furthermore, this can sometimes take a while. Better to de-risk potential future costs and time from adding up and have your mechanic replace the four fuel injectors now. 

Tip #5: Buying Four Injectors is Sometimes Cheaper Than Buying One ​​— Bulk Order

In some cases, buying the entire set of diesel fuel injectors for an engine like the D24 or D34 means you can actually pay less when you divide the cost of each injector. We personally discount our set of fuel injectors vs when someone purchases a single injector from us. Buying in bulk is usually more economical. 

To rebuild or purchase new? We recommend purchasing new fuel injectors. 

You can either purchase a new injector or send them out to be rebuilt. Oftentimes, sending your used injectors to be rebuilt can take a long time and end up costing you more in the long run. We also don’t recommend rebuilding them at home due to the complexity of this process. Facilities that specialize on rebuilding fuel injectors work and operate out of clean environments in order to prevent particles such as dirt or dust from contaminating these parts.  

Do you have any other tips worth keeping in mind when considering, “do I have to replace all injectors or just one?” If so, email us at We’d love to add them to this list. 

We hope this was helpful. Don’t hesitate to reach out with questions on your parts or if you’re searching for a part. 

Are you looking for high quality diesel engine parts such as fuel injectors, fuel pumps, crankshafts, turbos and more? Specifically looking for new diesel fuel injectors? Check out our wide selection of fuel injectors for your machines.