How To Install Aftermarket Injectors

How To Install Aftermarket Injectors


Installing aftermarket injectors can be a difficult job for the uninitiated and can be dangerous due to the fuel or fuel vapors present. When it’s time to upgrade your injectors, it’s important to realize what kind of injectors you are working with. The process of How To Install fuel injectors is not difficult but can be time consuming.

There are two types of gasoline injectors that you will be looking at generally, and thats high or low impedance injectors or otherwise known as peak and hold vs saturated.

Tuning your vehicle is vital after adding fuel modifications


What’s the difference between Peak and Hold Injectors vs Saturated ones?

Before you can learn How To Install fuel injectors, you must understand the different types of injectors available.

Peak and hold injectors are low impedence and operate in the 1-4 ohm range. These kind of injectors truly do follow their namesake in the way they work and function. When the ECU or PCM actuates the injector, it sends voltage to injector until the peak current is reached.

During that time the injector will fire for a duration of one fuel injector pulsewidth and slightly reduced ( this held ) during that time. This kind of injector mimizes the injectors “fire” time and is faster to react than the saturated counterparts. However the constant holding of voltage to the injector can lead to faster failure due to extended heat to the coil inside the injector.

We’ll be installing these 750cc high flow RC Injectors today


Saturated Fuel Injectors run on a higher impedance than their peak and hold brethren, operating in the 10-15 ohm range.  These injectors are constantly “on” for the entire length of the injector pulsewidth, which reduces heat in the injector coil and extends injector life.

These high impedance injectors are usually not found in performance applications as they are slower responding injectors and smaller in flow design.

If you are purchasing aftermarket injectors, make sure to check our guide here for injector sizing. If you have a high impedance vehicle and want to switch to peak hold injectors, you will need an injector driver to adjust the ohm range for your injectors.

Injector Drivers are easy to wire in and convert your injector ohm range.
Injector Drivers are easy to wire in and convert your injector ohm range.

After you have taken the time to choose your injector size, the next up is to purchase your set of fuel injectors in a kit or individually. Now you will need fuel injector clips, or OBDI style clips for most aftermarket fuel injectors. Depending on your year make and model, you most likely will require new injector clips to convert and install your fuel injectors.



While many companies like BLOX racing and RC Injection offer plug and play conversion harnesses like the ones shown above, chances are you will need to wire in your injectors. Today we’ll be installing a set of RC 750cc injectors into Project SRT-4 to help reach the 500whp mark. Although our How To Install fuel injectors article can apply for many other types of injector.

OBDI Style clips on the left, stock SRT clips on the right

To begin open your fuel cap and undo the tank cap to release any excess pressure left over in your fuel lines or system. Next undo your battery negative terminal, if you own a factory stereo now is the time to locate your security code or call your dealer.

As with all of our how-tos and writeups, this is just a guide for informational purposes and if you do not feel comfortable working on your own car stop here and take your car to a mechanic. Pro Street is not liable for any damage, however directly or indirectly comes from modifying your own car. Fuel modifications involve fuel vapors and dangerously high chance of fire. DO NOT PROCEED IF YOU ARE NOT COMFORTABLE.

Our stock injectors


To begin locate your fuel feed and disconnect the quick connect fitting, allow fuel to drip dry from the fitting and set safely to the side.


After this fitting is removed you can now move onto the 12mm pegs that secure your fuel rail to your cylinder head. Make sure not to lose the metal spacers during this job, and make sure you do not drop these spacers down your intake manifold or engine bay.


Here is a shot with all the pegs removed and ready to slide the fuel rail and injectors up and out.


Next line up your injectors and install your fuel orings if they are not already on your injectors. If you have clips now is the time to get them ready for wiring into your vehicle.


Lift the stock injectors and fuel rail out of your intake manifold and make sure you do not drop anything down the injector bosses that are machined into your intake manifold.

Carefully and slowly remove each stock injector from the rail until you have removed all your stock injectors. Next lube the top oring of your RC Injector with a small amount of dielectric grease or white lithium grease to help ease into your fuel rail without tearing.


Take your time during this process as any tearing or pinching of your orings may cause leakage. Once you have all the RC injectors installed, snug them down on your intake manifold and reinstall your 12mm pegs.


With all the injectors installed and clamped down, put the car to the “ON” position and make sure your fuel rail and lines have been pressurized. Check for any leaking at this stage, if you are in the clear move onto the wiring, if not take off your rail and try to figure out what went wrong. Now you are more than halfway through our How To Install fuel injectors guide.


Next up take your stock injector clip and note it’s orientation, make sure you install your aftermarket OBDI style clips in the same direction so that you don’t mix any of the wiring up.


Although you can solder each connection, it’s usually best to use injector clip butt-connectors as to not alter the nature of the injector wiring. Once you have tightened it all down and installed your injector clips you are now ready to test start the vehicle and check for any leaks!

Double, triple and quadruple check your fuel injectors, the fuel injectors bosses and all orings for any signs of leaking or failure. If everything checks out you have now successfully completed your fuel injector install! You now know How To Install fuel injectors in your performance vehicle!

Happy Tuning!