Picture of the MSD Atomic EFI Module

Atomic EFI

We’ve blogged before about how to power many different EFI systems with Infinitybox.  Examples include the Ford Coyote ECU, the GM LS ECU, the Holley Dominator, the FAST EZ-EFI and many others.  This post is going to cover how to wire the Atomic EFI system from MSD.

Here’s what MSD says about their Atomic EFI:

“The Atomic EFI provides the performance and driveability benefits that you expect from fuel injection. Quick starts, smooth idle and great throttle response just to name a few. Combine the fact that the Atomic will support ignition timing through the ECU and you have a win-win combination. Initial timing is handled through a compact handheld monitor where you simply answer a few car guy questions about your engine and you’re off and running!”

Just like any other EFI system, wiring it with our Infinitybox 10 or 20-Circuit Harness Kit is very easy.  You get several advantages over wiring with a traditional wiring harness.

  • You run less wire in the car.  The ECU sits behind the dash and connects to the MASTERCELL.  The cooling fan and fuel pump are wired to their local POWERCELLs.  You’re not running wires from the ECU all over the car.
  • You can eliminate the need for relays and external fuse holders.  The POWERCELLs are your relays.  Each output is fused inside the POWERCELL.
  • You get security and immobilizer functions in your Infinitybox system.  You don’t have to add a separate alarm system to keep unwanted people from starting your car.
  • You can get cooling fan timing and delays right in the Infinitybox system.  You don’t need to add separate controller modules.

Before you connect your Infinitybox system to your Atomic EFI system, you must completely understand the instructions from MSD.  Click on this link to get to the manual for their Atomic EFI PN 2910 – Throttle Body Kit.  This post is going to show you how to wire the key-on power to the Power Controller.  It will also show you how to wire ground, constant battery power, the fuel pump trigger and the cooling fan trigger.  See the MSD manual for the rest of the electrical connections to their harness.

This diagram will show you the details of wiring your MSD Atomic EFI system to your Infinitybox system.

Picture of wiring diagram showing how to wire the MSD Atomic EFI Power Module with the Infinitybox 20-Circuit Kit

Picture of wiring diagram showing how to wire the MSD Atomic EFI Power Module with the Infinitybox 20-Circuit Kit

To start, you need to connect constant power and ground to the MSD Power Module harness.  MSD recommends connecting the large red wire directly to the battery.  The ground wire should get connected to the chassis through a metal-to-metal connection.

The small red wire is the key-on power wire to the Power Module.  When you key is in the on or start position, you should have battery voltage on this wire.  The small red wire in the MSD harness is going to connect to the ignition output wire on your POWERCELL.  Check the configuration sheet that came with your kit for the correct color and connector orientation for all of the POWERCELL connections.

There are two wires in the MSD Power Module harness for cooling fan triggers.  The pink wire is the primary and the tan wire is for the secondary cooling fan.  Both of these wires are intended to ground a relay coil to turn on the fan.  You can connect them directly to the MASTERCELL inputs.  The MASTERCELL inputs are expecting a ground trigger to turn on the inputs.  You must put a diode in-line between the Power Module fan trigger wires and the MASTERCELL input wires.  This should be a 1N4001 diode.  The orientation of this diode is critical for this to work properly.  See the diagram above for correct orientation of the diode.

Once you have the MASTERCELL input wired to the Power Module for the cooling fan trigger, you need to connect the POWERCELL output to your cooling fan.  See the configuration sheet that came with your kit for the proper wire color.  If you want to use a secondary cooling fan, you can use any of the OPEN outputs on your system.

There is a large orange wire on the Power Module harness for the fuel pump.  This wire puts out a positive signal for the fuel pump.  You will need to invert this signal to a ground signal to work properly with the MASTERCELL.  You can use a relay to do this.  This link will show you how.  The easier way to do this is to use one of our inVERT Mini‘s.

Once you have the MASTERCELL input for the fuel pump properly connected to the MSD Power Module fuel pump output, you need to wire your POWERCELL output to your fuel pump.  Again, your configuration sheet will shows which wire to use.

That’s it.  All of your relays and fuses are built into the Infinitybox system.  Once you follow these steps, you’re ready to power up your system and start tuning the engine.

You can download a PDF copy of this wiring diagram by clicking this link.

Contact our technical support team with any questions related to wiring the MSD Atomic EFI system with your Infinitybox system.

Wiring the MSD Ignition System

Our Infinitybox systems are used to power all of the electrical functions in your car.  This includes all of the systems that run your engine.  One of the most popular ignition systems in the automotive restoration and performance space is from MSD.  The MSD 6AL is a powerful and easy to install Ignition Control system.  It gets the spark to the engine but our Infinitybox system gets it the power it needs to run.  This blog post shows how easy it is to wire on your key-on or ignition power to the MSD 6AL.  This instructions will work for any of the Ignition Control systems in the MSD lineup.

Before you get too far, it is very important that you read and follow the instructions that come with your ignition system.  We are going to show you how to wire the key-on power.  You need to refer to their instructions and diagrams to wire all of the other connections that go to their box.  Their manual highlights warnings and critical things to follow when you are wiring their boxes.  Be sure to read these and completely understand them before you proceed.  You can download a copy of the MSD manual by clicking on this link.

Also, this blog post and wiring diagram show you only how to wire the key-on power to the ignition system.  See the manual that came with your Infinitybox harness kit and other wiring diagrams for the rest of the functions in the car.

This picture shows you a simple diagram for wiring the MSD 6AL.

Image of wiring diagram showing how to wire the MSD 6A with the Infinitybox system.

Image of wiring diagram showing how to wire the MSD 6A with the Infinitybox system.

There are three wires from the MSD 6AL that we will consider for this wiring diagram.  The heavy red wire, the heavy black wire and the smaller red wire.

  • Heavy Red (Positive)- This wire connects directly to the battery positive (+) terminal or to a positive battery junction or the positive side of the starter solenoid. NoteNever connect this to the alternator.
  • Heavy Black (Negative)- This wire connects to a good ground, either at the battery negative (-) terminal or to the engine.  We can’t stress enough the importance of good ground connections.  Spend some time here and do this right.
  • Red- This wire connects to the POWERCELL ignition output on the Infinitybox system. See your configuration sheet for the location and color of this wire.
  • Connect the remaining wires according to the MSD instruction manual.

The heavy red wire that brings the primary power from the battery is fused internally to the MSD 6AL but this does not protect the wire if it were to get shorted to ground.  We recommend putting a fuse ahead of this wire at the point where you connect it to the battery.  A 25-amp fuse in this wire would safely protect it.

You are then going to connect the MASTERCELL input for ignition to your ignition switch.  The input works by simply being connected to ground.  See the configuration sheet that came with your kit for the connector location and wire color for the ignition input.  You can also choose to use our integrated one-button start input to control both the ignition and the starter.  Again, see your configuration sheet for the location and color of this wire.

The POWERCELL ignition output is your key-on power.  You are going to connect this to the red wire on the MSD.  You can also use this wire to power other accessories in the car that need ignition power.  Examples include gauge power, ignition power for a head-unit and ignition power for a Vintage Air system.  You can create a simple ignition power bus using a terminal strip for all of these functions.  You can use the Infinitybox Splice Saver Kit to create a reliable buss bar. 

You need to insert a fuse into the POWERCELL to protect the ignition harness.  Remember that a fuse is designed to protect the wiring in the harness.  The fuse should be sized to protect the smallest gauge of wire in the harness connected to that output.  All of our standard harnesses are 14-AWG wire, so you can protect them with a 25-amp fuse.  If you connect any smaller wires to these outputs, you need to choose the right size fuse to protect the wire.  See other posts in our blog about proper selection of fuses for different wire gauges.

You can download a PDF of this wiring diagram by clicking this link. 

If you have any questions about this wiring diagram or anything else with our Infinitybox system, give our technical support team a call.  We can be reached at (847) 232-1991 or  You can contact our team directly by clicking this link.