[jpnovak]

Recently there have been a large number of questions about installs, build threads with EFI swaps and yet, there was not a good collection of information in one spot. This post is to conceptualize the setup and tuning process of a stand-alone system. I told myself a long time ago that I would write a dialog to help answer most of the questions I get on a regular basis. This is what I was able to put down on “paper”.

This is a compilation of emails, texts, and posts I have sent to many of you on the BBS. So, It may seem familiar to some. If you are new to EFI or if you are considering EFI swap for whatever reasons this should help you.
I will not cover all the basics because there are other resources available. The books by Greg Banish as well as all ECU tuning manuals are a great place to start your Journey to EFI. If you prefer the video method then I highly suggest that you pay for and subscribe to HPA tuners. Their library is unmatched.

I will also say that you should not try to DIY an EFI system without some concept of electronics; including wiring, circuits, computers, and also concepts of how an engine works related to fuel delivery and ignition timing. None of what is in this post will make sense without some basic background.
The examples I give will be based on a Megasquirt platform but the process is the same. I have used the same techniques on MS, AEM, Motec, BigStuff, ECU Masters and others. Some of the parameter names are the same and some are different with the same function. This is not meant to be an exhaustive tuning guide. But, this will get you to a knowledge level that will not only get the car running but allow you to self-tune and have the car drive very well.

As you consider an EFI system, make sure you choose an ECU that your tuner understands. Maybe that is a shop - Every shop has a favorite. Maybe that is you. In this case, be willing to spend hours over weeks and months learning the hardware and software functions to take advantage of EFI; there is no shortcut to DIY, you have to commit to putting in the time.
Disclaimer: I have spent more than 15 years doing EFI systems. I researched for a few years before I pulled the trigger. You can do serious damage to an engine if you get things wrong. In a high-performance build you can do serious damage when you are on the edge of doing things wrong. So. Don’t F-Up your engine.

However, if you get it right EFI can do things that CIS, Motronic, Carbs and yes, even MFI can’t do. I will not be doing a comparison of those systems here. There are 20+ years of archives you can search in Pelican to find comparisons and reviews. There are also a ton of online resources that can be found with a simple web-based search.

Before you get started with tuning your EFI system it’s absolutely imperative that all of the mechanicals are dialed in and operating as they should. The most important thing you can do to set yourself up for success is balancing your ITBs. If your throttle bodies are not balanced, no amount of tuning will make your car run well and you will be chasing your tail. This guide will not go into how to balance your ITBs or set up the linkages as each system varies. Do keep in mind that balancing the ITB’s is not done at idle but also at 3000 and up. You want your car to drive well, not just to idle well.

The other key thing to remember is that tuning EFI is so much about making a single change, looking at the data and then refining. The beauty of EFI is that you have copious amounts of data at your fingertips. You don’t need to listen to or smell the engine to know if it’s rich or lean. Tuning EFI systems takes time and getting a really good tune without a dyno or professional is absolutely possible if you approach each step methodically and driven by the data.

These will be links to individual posts for quick navigation.

Terms and Definitions
Load Models
Sensors
AFR Targets
Ignition
Road Tuning
Idle Tuning
Cruise Tuning
Acceleration Enrichment
Fuel Scaling
Maximizing Resolution
Datalogs and Analysis