Quality Rebuilt Versus New Injectors

Mechanical diesel fuel injectors

  Make the correct choice when you purchase injectors for your diesel engine.

There are many injectors on the market today for diesel engines, some are new and some are rebuilt. Many people think new are better than remanufactured, however the correct answer is it depends. If they are not Original Equipment Manufacture (OEM), then new will not be as good as a quality rebuilt injector. OEM means the original Fuel Injection Equipment Manufacture (FIE), not necessarily the engine manufacture. There are a lot of variables with what may be called a rebuilt or remanufactured injector. Noted below are the variables to consider when purchasing injectors for your application.

Some will-fit aftermarket new injectors have such poor build quality, that we can not use the injector bodies during the rebuild process. The quality is such that there are multiple failures, even with installing OE nozzles. Non OE injector bodies will receive no core credit, as they are often junk.

The 3 on the left are aftermarket, notice the gap of the retaining ring where the hold down nut goes. The aftermarket ones have too large of a gap, which damaged the body and were not holding the injector at the correct torque. The one on the right is a Bosch OE injector.
What wears out in an injector?

The injector nozzle is the most common worn component in a mechanical injector. It is subjected to millions of opening and closing cycles during its lifetime. A little math would show an injector opens and closes 60,000 times during 1 hour of operation at 2000 rpm. Nozzles are also subjected to potential contaminates in the fuel as well as combustion gases. Poor quality air or fuel filtration will result in scoring, erosion, and other damage to the nozzle assembly.

What other components wear out in an injector?

Mechanical injectors are simpler than common rail injectors. Sometimes springs, nozzle guides or inlets need replacement, but usually at much higher hours of operation than the nozzle. Common rail injectors are more complex, with additional parts that can cause problems when worn. Additional parts that may need replacement include the armature, and valve body (ball seat).

What do you replace when you rebuild a mechanical injector?

We replace the nozzle 100% of the time with a genuine OEM nozzle from the OEM manufacture. There are a few exceptions to this, such as when a nozzle is no longer produced by the OEM. The remaining components are inspected and replaced as required. Opening pressures are set within 2%, for a balanced set of quality rebuilt injectors.

Do you use reman nozzles when you rebuild injectors?

The injector nozzle has had millions of cycles during its original life. Cleaning the tip and regrinding the seat is like putting lipstick on a pig, it is still a pig. A reman nozzle will not perform as well as a new OEM nozzle.

Why do you use OEM nozzles and components?

The OEM parts perform as the original part did, and if there have been updates, we update the rebuilt injector. The OEM parts will perform the same as the original part and the durability will be the same as the original part.

Do you use aftermarket Chinese parts?

No, our experience reveals that many aftermarket parts do not perform as well, nor do they have the durability of OEM components. We have seen aftermarket bodies with 10k miles pounded out by the nozzle and looking like they have 300k miles on them. We have seen aftermarket nozzles that stick or have poor spray patterns after a short run time. Testing reveals a wide spread of opening pressures or fuel deliveries. Simply put, they will not perform as well or last as long due to poor quality and engineering.

Are new aftermarket injectors any good?

New injectors that are not OEM, are not built to the same standards as OEM. Some suppliers sell a new, non-genuine injector for various applications. The older the application, the less likely it will be an OEM injector. Verify if it is an OEM injector, and where it was manufactured, before you purchase. OEM nozzles are available long after the injector assemblies are no longer produced new, making our factory authorized rebuilt injector a better-quality assembly

Can you verify if a common rail injector is good if you test it?

If we are testing Bosch common rail injectors or 6.4L Powerstroke injectors, the answer is yes. There are multiple test steps that would verify proper operation throughout the operating range.

Diesel Common Rail Injectors

What if one injector tests bad out of a set?

We have found a wide variance in fuel deliveries for performance injectors. Recording fuel deliveries and comparing it between different brands of 90HP injectors may be a 10-12% flow difference. Even plus 33% injectors flow different total flow rates between brands. You really do not want to mix brands. If you have performance common rail injectors and the manufacture is unknown, they should be tested in as a set to identify deliveries and flows that could be out of balance. If they are out of balance, delivery wise, or fail testing, a replacement nozzle of the same brand should be installed. When you do not know the brand, you may want to replace the entire set of injectors. Most aftermarket performance injector nozzles do not have identifying numbers such as spray angle or hole size on them. Or if they started their life as an OEM injector and were extrude honed, then the size would be unknown.

Can you verify if a mechanical injector is good if you test it?

If we are testing a mechanical injector, then you can tell if it is bad, but not necessarily if it is good. Spray pattern, atomization and opening pressure are checked, but you cannot tell reliably if an injector is sticking unless you remove the nozzle, inspect, and check the needle. An injector will open 6 times per second at idle, and over 21 times per second at 2600 rpm, you can not duplicate that with a pop tester. Spray angle and volume of fuel from a mechanical injector are not easily determined.

Oregon Fuel Injection is a factory authorized repair facility and uses Original Equipment Manufacture (OEM) nozzles and components from Bosch, Delphi, Denso, Stanadyne, Ambac and Yanmar. We are also factory authorized by Bosch for testing common rail injectors.

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