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EFI Expert Holley EFI Technical Information

On this page I will post documents, notes and videos pertaining to the Holley EFI systems.

Obviously you will probably have questions so don’t hesitate to email me.

Or call me at 209-247-6497

August 2017: A surprise article showed up on the Hot Rod Magazine web site:

New product offering for Mopar people who want to go CNP. 

Click HERE to go to the CNP page

Wiring diagram is at the bottom of this page

Here is a link to a pretty good

Video about the Terminator - X line

Here is an Excel Spreadsheet

that compares the terminator-X line to the other Holley products

Holley now offers a plug-and-play harness for the Gen-3 HEMI.

Click on the link above to see specific instructions about this harness.  You will see two different part numbers:

558-115 and 558-116.

The 558-115 is for early HEMIs that use the 36-2 waste spark crank trigger.  The 558-116 is for the later 60-2 fully sequential engines. You must know what crankshaft sensor you have.  These harness are both for cable driven throttle bodies.

I also offer a special DBW harness option if you so choose for the Dominator only. (Late pedal with the compact Molex connector ('08-2012 Up cars, '07- 2012 Trucks). The 0459 1847 factory drive-by-wire throttle body has been pre-calibrated and approved for use with these harnesses.


Holley EFI has released Version 4 of the EFI software.
You can download V4 from:

There are many enhancements but one particularly nice feature is in the Global Folder arena.  Since I assist most of my customers via email I always ask you for the current program. Holley has previously stored programs in a “Global Folder” which was just a Windows folder that contained multiple files.  You had to Zip the entire folder in order to send it.  V4 still uses the global folder terminology but everything is stored in one file.  That makes it much easier for you to attached it to an email.  V4 will automatically read V2 and V3 folders and converter them to V4.  There are many other enhancements that you can peruse yourself but downloading HERE.



What? No Installation Instructions or Documentation?

All documentation is included within the software.  Install the appropriate software and go to Help.  All the information is there starting with the installation.



Helpful conversion formulas:

I don't know how many times people have asked "what the hell is a kilopascal" in terms that they are used to thinking about.


To Convert                          Multiply By   

Atmosphere to inches of mercury     29.921253      

Atmosphere to kilopascals (Kpa)     101.325

                                    (that's why the "football" of a non-running engine is about 100

Atmosphere to psi                   14.69595        

Inches of mercury to atmospheres    0.0334211      

Inches of mercury to kilopascals    3.37685          

Kilopascals to atmospheres          0.0098692      

Kilopascals to inches of mercury    0.296134   (minus one atmosphere)

                                    (so a kPa of 53 is about 15 inches of mercury)

Kilopascals to psi                  0.1450377      

Pascal to psi                       0.000145        

Psi to atmospheres                  0.068046        

Psi to inches of mercury            2.036021        

Psi to kilopascals                  6.894757


Injector Types:

There are many different styles and types of fuel injectors but here's a picture of the basic normal vs stubby types. Note also that there are different connectors with the most common being EV1 and EV6. Also here is the injector offtime information for Holley injectors.

IAC Wiring Considerations


Here's a drawing of the IAC wiring options. Customers buying the Holley EFI systems do not realize that Holley likes to use Chrysler IACs because they flow more air than a standard GM LS style.  If you are configuring a system that uses a "standard" GM IAC you will have to make a minor wiring change in order for the IAC to work.


To find out whcih type of IAC you have, look at the drawing below.

With an ohm meter measure between the center two pins (B and C) of your IAC.

If it’s an open – you have a GM style IAC.

If you see resistance you have a Chrysler style IAC

Here's the wiring for the Mopar CSS-HPT pigtail for the Holley HP and Dominator.

Crank and Cam Pigtail Harness 2.jpg

* Holley HP or Dominator Kit


This is the complete Mopar kit that will work with either the Holley HP or Dominator systems. It is Plug-and-Play. Nothing has to be custom cofigured.

Here's the Holley Ignition setup.

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