Injectors FAQ

Injector stuck open

Contact Nostrum if any injector issues are suspected. Email: support@nostrumshop.com

Injector not firing (stuck closed)

  • Verify that the connectors are secure and no wires are broken or unplugged.
  • Check that there are no codes on the ECU precluding the injectors from firing, and that there is fuel pressure available.
  • Check that the fuel pressure has not exceeded the maximum design pressure of the injectors.
  • Make sure the injector drive current is appropriate (for applications where this is a tunable parameter).

If you are still having trouble, please contact us directly at info@nostrumshop.com

Vacuum leak at the manifold/injector seal

If you suspect a vacuum leak at the manifold or injector seal, make sure that the factory o-rings didn’t come off, the sealing surfaces are clean, and the new injector o-rings are properly seated. It is recommended to wet the o-rings with fuel slightly before inserting the injector as this will help prevent them from binding and rolling over.

Leak at the fuel rail seal

Ensure that the factory o-rings have not ended up inside the rail when the original injectors were removed, the fuel rail is clean, and that the new o-rings are properly seated. It is also recommended to wet the o-rings with fuel slightly before inserting the injector, as this will help prevent them from binding and rolling over.

My car is not running properly after installment of Nostrum injectors

Nostrum Injectors are designed to flow higher quantities of fuel than the factory injectors, therefore they will not work with an engine that is still running the factory ECU calibration. Tuning is required for all aftermarket injectors. Improper tuning may result in poor engine performance or even engine damage.

What is the “Kinetic Mechanism” and why does it matter?

Nostrum’s patented kinetic colliding jet technology relies on bringing multiple jets of fuel together at a central focal point to create a collision that atomizes fuel spray up into much smaller fuel droplets. The superior atomization results in more power, better efficiency, and lower emissions.

What is “Split Gamma” and why does it matter

“Gamma” refers to the angle between two separate fuel spray plumes. A Split Gamma injector has two distinct fuel sprays, each one individually aimed at the back of the intake valve. This is very important because every engine in production today has two intake valves, so fuel injectors that produce only one fuel jet tend to wet the divider between these two air paths.

See examples of a Split Gamma injector here.

What is “Spray Targeting” and why does it matter?

Spray targeting is the process of using Computational Fluid Dynamics (CFD) to aim the fuel spray plume accurately away from the walls. This targeting exercise considers the airflow in the intake port and how it affects fuel spray travel. The result is a fuel spray that has the least possible impingement on the intake ports.

Fuel injectors are rarely installed with a direct path to where the fuel needs to go due to design constraints. Compounding this issue, the high velocity airflow in the intake path of the engine also has a strong tendency to guide the fuel spray towards the walls of the intake port.

The reason we never want fuel to end up on the intake ports and manifold walls is because once it collides in these places, it will coalesce into a liquid film. As this happens, some of the fuel evaporates off those walls, displacing the air, thus reducing the volumetric efficiency of the engine (which reduces horsepower).

The fuel that does not evaporate off the intake port and manifold walls runs into the engine as large droplets. When this happens, the fuel doesn’t evaporate or mix with the air well. This is one of the reasons why engines with aftermarket fuel injectors tend to have trouble starting when cold, particularly on ethanol based fuels which are less volatile than Gasoline.

Troubleshooting FAQ

Can I install K-DI Injectors myself?

Yes – but we don’t recommend it unless you’ve had previous training or experience. Go through a tuner for the best results.

However, if you want to learn to do it yourself, we highly recommend our partner tuning school, EFI University, as the best place to do so!

If you feel confident enough to DIY, check out our YouTube Instructional Videos to follow along.

Where can I tune my car?

There are various tuners, Nostrum recommends the following:

For GM LT: Lingenfelter

For Ecoboost: COBB

What size (flow rate) of injectors should I buy?

Fuel injector flow rate depends on the number of cylinders, how much power is desired, and the fuel type being used.

Generally speaking, alcohol type fuels will demand considerably more flow from the injectors for the same power output (approximately 30% more for E85).

A rough estimate on size can be obtained if you know the flow rate of your factory injectors and how much horsepower they can support in your application.

Type in your vehicle application specifics under the “Products” tab dropdown to see which injectors are available for your platform. Or contact us at support@nostrumshop.com for assistance in choosing the right injectors.

Does fuel pressure affect injector flow?

Increasing the fuel pressure will increase the injector flow rate as follows: Square Root (New Pressure/Old Pressure). For instance, doubling the fuel pressure will theoretically raise flow by approximately 41%.

What is the maximum fuel pressure that I can run?

Maximum pressure is application dependent, but varies from 160Bar to about 220Bar. It is not recommended to go above the maximum factory pressure, because it can severely reduce fuel pump life, and does not result in a dramatic increase in flow rates.

Nostrum recommends maintaining the factory fuel pressure settings; our injectors flow more than stock at any given pressure! As always, contact your tuner for application specific questions.

What is injector latency?

Injector latency is the lag time between when the injector is commanded to open and when it actually opens. Maximum pressure is application dependent, but varies from 160Bar to about 220Bar. It is not recommended to go above the maximum factory pressure, because it can severely reduce fuel pump life, and does not result in a dramatic increase in flow rates.

Nostrum recommends maintaining the factory fuel pressure settings; our injectors flow more than stock at any given pressure! As always, contact your tuner for application specific questions.

What is fuel injection pulse width?

Fuel injection pulse width is the time (typically expressed in mili-seconds, ms) the injector is commanded to be on by the engines ECU. Fuel injection pulse width is calculated by the ECU based on measured or inferred airflow, and the fuel injector flow curve.

How can I clean my fuel injectors?

Under most conditions you should not need to clean your fuel injectors. However if you do, Nostrum offers this as a service. Contact Us for details.

What does “direct fit” mean?

Nostrum Fuel Injectors are designed to be a direct-fit. This means they drop-in to the factory application exactly as factory injectors would, without adapters, pigtails, or any other changes.

What does “retro-fit” mean?

Retro-fit means to add a component or accessory to something that did not have it when manufactured. In the case of the GM LT engine series, a fuel rail adapter as well as a wiring harness adapter are provided to ensure a perfect fit. These are bolt-on components, requiring no wiring or mechanical changes to the engine, and retaining OEM quality throughout.

Do you provide training for calibration associated with your K-DI injectors?

Nostrum Energy has partnered with EFI University to create a Direct Injection Calibration Course where you will learn how to calibrate a direct injection vehicle. View the course information here: https://www.nostrumshop.com/product/direct-injection-tuning-course/

There are also shops that are familiar with tuning direct injection vehicles that can handle this for you.

Why are the K-DI injectors application specific? Can I purchase a universal K-DI injector?

Each component in an engine is specific to that engine design and engine architecture. Fuel delivery is very specific to that particular engine’s combustion system. The way air travels through an engine’s intake manifold, down through the cylinder head ports, around the intake valves and throughout the combustion chamber significantly impacts combustion quality.

Direct fuel injectors (GDI, DI, DIT, SIDI, etc.) are designed to spray the fuel into the combustion chamber with this air motion so that fuel exits the injector in a way that allows it to mix well in the chamber and avoid as much surface contact as possible. This is what engineers refer to as the “combustion system”.

Nostrum uses advanced computation fluid dynamic tools to design the K-DI products so that the fuel spray mixes well with that particular engine’s combustion system. The K-DI nozzle for the GM LT engine is very different than the VAG EA888 engine which is very different than BMW N55 engine.

A universal type KDI injector, which could have a very generic or arbitrary spray pattern will create combustion issues, from impingement on surfaces or rich-lean regions in the chamber, that will not be possible to calibrate the engine, resulting in poor operation, and could result in engine damage. Therefore Nostrum does not sell a universal direct injector.

If you have an application not seen on our site yet, please send us an email and we will evaluate your application for our product plan.

Why are the K-DI injectors so expensive?

Direct injection fuel systems operate at higher pressures than traditional port fuel injection (2000-3000PSI, compared to 40-80psi for PFI), and operate at higher voltages as well (55-60V as compared to 12-14V). The manufacturing tolerances and precision required are much higher, and this is reflected in the price per unit.

Our products are engineered and manufactured as OEM injectors. These are not re-purposed or modified (ground or drilled) stock injectors.

Our K-DI products use a completely new high pressure nozzle. So let’s get technical: The nozzle is Swiss and CNC machined, made from heat treated 420 stainless steel. The pintle valve seat is precision ground with a 0.001mm circularity tolerance, a 0.003mm run-out tolerance, the 120 degree seat angle is +/- 0.5 degrees, and the seat depth is well within 0.005mm depth. The fuel orifice hole diameters are between 0.250mm to 0.400mm with a 0.015mm diameter tolerance and a 0.035mm true position tolerance. These orifices are EDM’d (electrical discharge machining – see more here https://en.wikipedia.org/wiki/Electrical_discharge_machining ) and then HEG’d (hydro erosive grinding – see more here https://en.wikipedia.org/wiki/Hydro-erosive_grinding ) to produce nozzles that flow within 1% of each other and to the target flow rate. Then the nozzle is electron-beam welded (EB-Weld see more here: https://en.wikipedia.org/wiki/Electron_beam_welding ) to the pintle shaft on the injector assembly.

Not only that, we use OEM injector cores, which are precision machined for nozzle assembly. We reset the solenoid gap in each injector to increase the fuel flow. Then every injector is leak tested, pressure tested and flow tested at multiple pressures with the new Nostrum recommended drive current. These processes and tolerances at low volume (when compared to OEM volumes) drive a much higher price point than “re-purposed” or “ground down” injectors.

What is the maximum fuel pressure I can run on a port K-ITI fuel injector?

Nostrum PFI Injectors have been tested to open up to 10bar in fuel pressure, but are not generally recommended for usage beyond 5 bar due to durability concerns.

Can I use methanol in your water injectors? Do I need to run any special water in your water injectors?

Nostrum Water Injectors are designed for Water, Alcohols (Methanol or Ethanol) and any mixtures thereof.

Why do I need to purchase some K-DI injectors from a tuner’s website, such as Lingenfelter or Xtreme-DI?

Direct Fuel Injection systems are considerably more complex than traditional Port Fuel Injection, and vehicles in need of fuel system upgrades are already modified enough from their OEM configuration to need calibration changes. For those reasons, whenever possible Nostrum has partnered up with leading companies in their segment for their fuel injector distribution so as to ensure the success of our customers.