How Often Should Fuel Injectors Be Replaced? –

Signs It Is Time To Replace Your Common Rail Fuel Injectors

Knowing when to replace defective fuel injectors can make all the difference in the world. We have put together a quick guide of common signs that may tell you it’s time to replace your fuel injectors. Remember, these are just the most common signs, but not the only ones.

For starters, decreasing fuel efficiency could be a sign that something is wrong. Couple that with a decrease in power and it’s almost certain that something isn’t right with the injectors. 

A raw fuel smell is another indicator that something is wrong. We all love the smell of fresh diesel in the morning, but it should not be coming from your exhaust pipe. Get the injectors checked out as soon as possible by a reputable shop like HHP.

Engines, diesel or not, are carefully engineered to keep all liquids away from one another. Unfortunately, that does not always work out well. Diesel fuel can end up making its way into the crankcase via worn-out O-rings or defective fuel injectors. Not only will it reduce the lubricating properties of the engine oil, but can also cause a whole host of other issues. 

Lastly, engine misfires are a common sign that your injectors may be defective. Unfortunately, an engine misfire can be caused by several issues ranging from a loose or severed wire to low compression. If you are unsure about what the root cause of the misfire is, get a reputable shop to determine why it is misfiring in the first place.

Looking for new injectors but don’t know where to start? No problem! Highway & Heavy Parts has a post all about choosing the right fuel injector here.

How Often Should Injectors Be Replaced?  

On average, diesel fuel injectors should be replaced every 95,000 miles. Of course, several factors go into play such as operating conditions, the load being put on the engine, and the quality of fuel used. 

If you bought the vehicle used, a thorough inspection will tell you how much life is left on the injectors and other vital key components. You can even send your injectors in to have them flow tested. Don’t wait until it is too late by ignoring the common warning signs. It will just end up costing more time and money in the long run.


Is it expensive to replace fuel injectors?

Depending on the make and model of your car, the average fuel injector replacement cost will run you about $800 to $1,450 for a full replacement. If you have the knowledge to do the replacement yourself, the parts alone are around $600 to $1200, while the labor cost is only about $200 to $250.

How do I know if my fuel injectors are clogged?

Five Signs Your Fuel Injectors Are Clogged or Bad
  1. Bumpy Idling. Rough idling is a sign that your automobile’s engine is not getting enough gasoline, and one reason why it might not be getting enough gas is that your fuel injectors are clogged. …
  2. Dancing RPM Needle. …
  3. Dead Engine. …
  4. Low Gas Mileage. …
  5. Misfiring Engine.
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Replacing a fuel injector should take 1 to 2 hours for a mechanic to remove and 4 to 5 hours for a non-mechanic to remove. The average fuel injector costs $150 to $600. The total cost of replacing the fuel injector can go up to $1100. 

There are several signs that show a fuel injector causing a problem in the engine, including consuming more gasoline to go the same distance. There may also be thick dark smoke coming from the tailpipe, and the engine completely refusing to start upon ignition. 

If the engine misfires, it could be because the fuel injector is actually dirty and it needs cleaning.

When should a fuel injector be replaced?

There are many other parts of a vehicle’s internal combustion system that will wear out faster than a fuel injector. But in certain situations, fuel injectors can gust, stop working, or become clogged. 

When a fuel injector is not working as it should, a vehicle will give us several noticeable signs that something is not working as it should. Here are a few signs that can tell a vehicle owner or mechanic that there is something wrong with the fuel injector:

● A vehicle will consume more gasoline to go the same distance

● When a vehicle is idling, the engine will be louder and rougher

● The driver will have to ignite the engine 3 or 4 times to finally turn it on

● Any smoke coming from the tailpipe will become darker and thicker

● The engine will work harder and anyone in the carriage of the vehicle will feel stronger vibration coming from the engine

● If a fuel injector is extremely damaged, the vehicle’s engine will not be able to start at all

All of these signs and a few others not mentioned here indicate that there is something wrong with a part of the engine. But these signs can also be symptoms of a different part of the engine. 

The only way to truly know if the issue is with the fuel injector is to connect the engine’s diagnostic system with a scanner tool. 

A mechanic will be able to do this, but a vehicle owner can buy this tool as well and use it at their home whenever there is an issue with their vehicle. 

What are the symptoms of a failing fuel injector?

An abrupt loss of engine power is a somewhat obvious sign of a fuel injector failure. If the fuel injector is clogged, the fuel supply will be irregular too. When the fuel level fluctuates drastically, the high and low rpm’s will cause the engine to move in surges rather than slow and gradual movements.

How to Change Your Fuel Injectors?

Fuel injector replacement needs special equipment and tools. You can shop for them at your local auto parts stores or order them online. If you’re skillful enough, then you can do it yourself. However, I highly recommend you get help from a professional.

When you take your car to a mechanic shop, expect to pay up to $1500 (this number varies on your make and model). The parts themselves are quite expensive, not to mention the labor cost. If you want to save some money you can go for aftermarket parts. So make sure you look around for your budget.

What Are Fuel Injectors and How Do They Work?

To understand how much it costs to replace fuel injectors and why it’s important to get it done, it helps to know more about how your fuel injection system works. Fuel injectors play an important part in the function of your car’s engine. Here’s a quick rundown of what they do:

  • Fuel injectors spray fuel into the cylinders of your engine.
  • There is one fuel injector for each cylinder in the engine.
  • The fuel pump sends fuel from the gas tank, through the gas lines, to the injectors.
  • Your car’s computer system sends signals to the fuel injectors to tell them how much fuel to spray into the cylinders.
  • The nozzle at the end of each fuel injector partially atomizes the liquid fuel into a spray that then enters the cylinder.
  • The cylinders then fire to trigger the internal combustion process that powers your vehicle.
  • The fuel injectors will spray more fuel over a longer spray when you accelerate and will spray less when slowing down or idling.

How Often Do Fuel Injectors Need to Be Replaced?

As a general rule, diesel fuel injectors will need to be replaced between 150,000 to 250,000 miles. For the best performance, they should be inspected by a professional every 50,000 miles.

This will obviously vary depending on how you take care of your engine. factors like:

  • Regular oil changes
  • Injector cleaner pneroidcally
  • Installing clean fuel
  • Replacing BOTH primary and secondary filters on schedule

Fuel Injector Replacement Cost

Best places to order parts?  See: 19 Best Online Auto Parts Stores

Fortunately, most fuel injector issues can be fixe

Fortunately, most fuel injector issues can be fixed with a professional cleaning or replacement of the O-rings if a leak exists there. But when a fuel injector cracks or breaks, replacement is necessary and it can be expensive.

Although fuel injectors are individual, they are designed to work as part of a team with the other injectors. So if you’re wondering if you can replace just one injector or all, the answer is almost always to replace them ALL.

Depending on your make and model, you can usually expect to pay around $800 to $1,450 for a complete fuel injector replacement. Parts alone are about $600 to $1200 and the labor cost will run about $200 to $250.

There are exceptions of course. Using non-OEM parts can save you some money while certain makes/models of vehicles can run upwards of $2,000 for a replacement. It makes sense to shop around for this type of job.

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Should I just replace the bad injector or all 8?

This is a great question but unfortunately, the answer is it will depend on your budget. As a whole, it will be better to replace all 8 injectors when you have one fail. If one injector is failing the other 7 are likely to follow suit. They were all manufactured around the same time. If you can afford it, it will save you money, time, and hassle.

Money does not always permit the best practices but it would be best if you are already having issues from one the rest are more likely to follow.

It is also a very good idea to go ahead and replace the injector wiring harness while you are in the crankcase. They often get brittle and begin to deteriorate abut the same time the injectors begin to fail. The heat and vibration get to everything in time.

Fuel Injectors Fuel Systems Resources

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How to tell if a fuel injector is bad?

There are many things to look for to determine if your fuel injector is bad. Some of the symptoms are the following:

  1. The check engine light is on
  2. The car idles rough
  3. You can smell gas
  4. Engine misfire

It is important to diagnose the problem before you replace your fuel injectors. Knowing what is causing the problem will help narrow down the possible cause.

If one of these signs is present, then it is a good idea to have a certified mechanic check out your vehicle. And inspect all components that could be causing the trouble. They can pinpoint the exact source of the issue and will be able to replace the part that is causing the problem.

You can use an OBDII scanner to get a code for the injector to narrow things down. If the code is for a specific injector, then that is the issue.

Final Words

Fuel injectors won’t last forever. They need to be replaced in due time. Whether you do it yourself or let someone else do it, the most important thing is to keep them checked on a regular basis.

Observe your car’s performance and if it doesn’t feel right, then the best thing that you can do is replace it. You don’t have to wait until they fail. Just follow these tips and you can extend their life span by quite a lot.

Changing fuel injectors is a major job that requires a lot of skill, patience, and experience. If you don’t have the right tools and experience, you might end up doing more harm than good. Take your car to an automotive shop if needed.

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