ECU Tuning - The Movement

It might seem hard, but tuning your ECU on your own isn't difficult. It just requires some basic tools, a lot of patience and plenty of research. Lucky for you, there are thousands of people who've already cleared a path-and they've put it all on the 'Net.

Among the many things we love about Honda is its emphasis on advancing technology, whether that encompasses variable cam timing, producing zero-emissions engines or building robots to help old folks live better lives (we get the shivers when we hear rumors of Honda contemplating entry into NASCAR). Honda's resolve to move the needle doesn't end on the factory or R&D floor. This exploratory spirit has filtered down to Honda heads populating the Internet and given rise to one of the most exciting grassroots tuning movements around: DIY engine control.

This ain't just dialing in cam gears. This is real car geek shit: laptops, chips, burners, code. It all adds up to what the core of these enthusiasts acknowledge as the PGM-FI Movement. Be warned: the following report from our own in-house car geek is not for newbies. It assumes a certain familiarity with engine management principles.

That doesn't mean beginners should shy away. There's a wealth of information out there, happily shared by the enthusiasts who've already taken a machete to the cluttered path. As one pioneer of the movement advises, get some strong coffee and a blank notepad with a lot of pages. Once you dig in, you'll find it hard to stop. - DF

Every Internet community starts with a visionary and some server space. Dave Blundell (screen name: Blundar) started what eventually became in the spring of 2002. The forum's humble beginnings were at a "borrowed" domain name ( Currently, the forum boasts more than 3,700 registered members, all working toward the same goal:

"PGMFI's final goal is for all Honda fuel injection systems to be well understood, properly documented and able to be tuned by [my] girlfriend," Blundar explains on his site. "It is not PGMFI's goal to turn everyone into a rocket scientist, but instead to make ECU tuning more accessible."

The majority of the site's members probably don't know Blundar's girlfriend. Blundar isn't even referring to his girlfriend, more the idea that programmable engine management software and techniques should be easy enough for all to understand.

Blundar says, "My girlfriend is very smart, but she is not all that mechanically or scientifically inclined. She represents an audience I want PGMFI's tools to be accessible and available to."

The first goal the group set for itself was to document the Honda ECU by disassembling it byte by byte. Developing a replacement for the stock program, commonly called "chipping," came next. A quick look at the circuit boards of an OBD-0 and OBD-I ECU shows Honda made chipping these boards easy. The ECU requires no major modifications, just a few additional components soldered into pre-marked locations on the board.

Although enthusiasts succeeded in unlocking and modifying an ECU, its lack of a visual interface made tuning less than user-friendly. Necessity being the mother of invention, a few ROM editors were written, three of which have become staples in the PGMFI world.

William Brown, better known as Jason Parker or TurboEF9 (his mom made him use a pen name on the Internet when he was young and it's stuck ever since), wrote a program called TurboEDIT. It's regarded as the premier OBD-0 ROM editor for DIY tuners. Over the past two years, TurboEDIT has progressed into an unrivaled OBD-0 tuning platform with a host of advanced features including 3-D fuel and ignition maps, datalogging, real time programming and map scalar editing.

"The only engine management available excluding [aftermarket] ECUs was either a rising rate fuel regulator, a piggyback unit, or this program that was just starting out called Ghettodyne," Brown explains. "I checked into Ghettodyne, found PGMFI, and started learning everything I could about Honda ECUs. Eventually, I decided to set out and write something myself."

OBD-I computers like the popular P28 ECU have received endless support and development from the members of the PGMFI group. Two of the more notable tools written for the '92-to-'95 Civic and Integra ECUs are berdata and CROME.

Blake Warner's berdata and John Cui's CROME boast loads of features that give any aftermarket stand-alone system a run for its money. berdata includes tools such as datalogging, real time programming, full throttle launch (two step) and programmable shift lights. The free version of CROME, meanwhile, includes dual table VTEC maps, built-in boost table adjustment, and built-in fuel multipliers (to take the guesswork out of tuning larger injectors). CROMEpro ($149) includes all of CROMEfree's features and tacks on advanced tools like datalogging, map tracing and user-definable auto adjustments.

Warner says, "berdata is, in short, a piece of software that enables you to modify your Honda ECU's code using a Windows-based program. Does this mean your Mom's Accord can use berdata? Probably not. You'll have to check the list of supported ECUs to see if berdata can be useful to you."

As of this writing, the PGMFI group has decoded, modified and replaced programs in almost every '88-to-'95 Civic and Integra ECU. There have been limited advancements on the pre-OBD ECUs, such as those in '83-to-'87 Civic/CRXs. Direct solutions for tuning OBD-II ECUs aren't available, but the groundwork is in progress. And according to Cui, people are documenting their progress on NSX and S2000 ECUs, which may someday offer the same tuneability as a Civic or Integra ECU. is now three years strong and in that time has grown from a couple of guys interested in tuning on the cheap to a few thousand people on a collective mission to push the limits of the stock ECU.

If you decide to check out the PGMFI scene, prepare for some sleepless nights and times when your brain will feel overloaded with information. But all the knowledge is there, free for the taking by anyone with the initiative to learn.

A word of caution: PGMFI's treasures aren't always well organized and the sites and forums can be very brutal on newbies. We can't stress enough to use the search function. And read. Read some more. Refresh your choice of energy-addictive drink and continue reading. This is not a community that gladly suffers fools and those in need of instant gratification.

And finally, remember that PGMFI is a collaborative effort. Even if you're not a programmer or an electronics master, you can help. New code writers always need testers and guinea pigs. If you're good with posting images on the Web, create write-ups and tech articles for others to learn from. The Web sites, test ECUs, chips, burners and other hardware needed to push the learning curve cost money. While the programs are free, donations are welcomed and well-deserved.

HT Talks with Some Key Players in the PGMFI Movement

Dave Blundell, founder of; John Cui, developer of CROME; Christian Dorner, better known as DOC from PGMFI; Jason Parker, from turboEDIT; and Craig Moates from

Honda Tuning: Let's open this can of worms. What role do you feel you play individually in the PGMFI Movement?

Dave Blundell:

John Cui: I'm the guy who puts everything together into a smaller, more manageable package. I write the software that people end up using so they don't have to memorize formulas and memory locations, and end up making changes to the ECU program one byte at a time.

Christian Dorner: I'm a researcher and developer, mainly for OBD I. I've spent a lot of time analyzing how the ECU works, hardware and code-wise. My findings result in development like datalogging code and a very simple board that allows you to tune your ECU in real-time (RTP). Evan Lathouras (Australia) and I developed our own RTP software called ProECU."

Jason Parker: I'm the author of the TurboEDIT ROM Editor. I help develop and promote the pre-OBD/OBD-0 camp, and recently OBD-I through a plug-in that installs into TurboEDIT.

Craig Moates: My role is to make very affordable, high-quality, easy-to-use hardware available for the DIY-EFI/PGMFI user via Since I'm an EFI vehicle owner and tuner myself, I have a solid perspective on what's useful. I'm always open to new ideas, and I take product/project suggestions seriously.

HT: Recent developments in hardware have opened up possibilities that at one time were reserved only for top-dollar engine management systems. Where do you see the PGMFI movement heading? What's over the horizon?

DD: Better documentation, more stable feature sets. In one word, accessibility. Both the OBD-0 and OBD-I scenes have advanced to the point where most common technical challenges have workable solutions. What's left is refinement of features using feedback from the people using them. Additionally, the programs available to help people need to become friendlier, or at least better documented. A large part of the goals of PGMFI is to further educate DIY'ers. I see this becoming a much bigger deal in the future now that many of the basic tools are available.

JC: I see PGMFI expanding to more than just Hondas. There are already ROM editors available for other make vehicles and more are coming out. Also, when the right information comes along, we won't be too far from being able to tune your NSX or S2000 with the stock ECU.

CD: The development will continue. We'll continue our work in the OBD-0 and OBD-I section to make things like boost control from the ECU possible. We'll continue working on the OBD-II computers and work has already begun on the new K-series/D17 ECUs.

JP: I think PGMFI is going full steam ahead! We've got some talented people aboard, and as the word gets out I see even more people helping the cause. There are some awesome things on the horizon for TurboEDIT. We've already got a great plug-in interface so that anyone can write TurboEDIT add-on functions and applications. Also, new achievements in the TurboEDIT ROM that will give us real-time programming through a custom board designed and built by our own PGMFI members. Advanced datalogging support, dual-map VTEC support through the PM6 ECU, wideband O2 sensor support-all previously available only on high-dollar engine management systems.

CM: The recent application of integrated datalogging, wideband and realtime emulation is key. I believe continued software development toward auto-tuning will be very interesting. By building in the knowledge of how to efficiently tune the vehicle, optimized performance may eventually be plug-and-play. If coupled with actual performance data, such as accelerometry or F = mA calculations, the possibilities become extreme.

HT: What are the limitations of modifying OEM ECUs? Are there engine setups that necessitate something beyond what TurboEDIT, berdata, or CROME have to offer? What can't you do with a stock ECU?

DB: Non-four-cylinder engines. Engines that a Honda/Denso distributor cannot be fit on (hint, hint). Coilpacks/coil-on-plug/ion sensing ignition systems.You can't flexibly control more than four injectors (it's already being done, but not in a simple, DIY manner). Proper acoustic knock monitoring. Other than those, the sky is the limit.

JC: With the right knowledge, modifying the OEM ECU is almost limitless. Most engine management systems are the same at heart: computers that sample sensors several times a second and produce the right combination of fuel and ignition timing based on what the different sensors read. The best thing about using the OEM ECU is that most of the hard work is already done. It's just a matter of manipulating small portions of the code to make it do what you want.

CD: At the moment, I don't see any limitations. It's not a matter of the ROM editor you use. The editor is just a front end for the user or tuner. The code on the ECU does the real work. If the code isn't written yet for a certain engine combination, it just needs to be written when the problem occurs.

JP: So far, any limitation that we've been presented has been overcome with creative programming techniques. Things like ECU processor speed and available math. Pre-OBD/OBD-0 ECUs use 8-bit math, but some of our calculations require 16-bit. So far, I haven't run into an engine setup that at least one of the PGMFI-derived software applications can't handle.

CM: I don't know of any limitations, other than the knowledge base with respect to factory code disassembly. The software guys have been great in this regard, so the user just needs to worry about timing and fuel. Those factory boxes are powerful pieces of hardware, with some extra stuff built in that doesn't normally get used.

HT: What is your take on freeware? Has your work in this field been rewarding, even if not monetarily?

DB: I do it for the chicks. Seriously, I've met more geniuses that I connect with on both a personal and intellectual level working with PGMFI than I can count. Even though I haven't had an OBD-0 car of my own for more than six months now, my personal project remains coding for the beloved CRX. I'm involved for the intellectual challenge. I've learned so much from my work with PGMFI, it has kept me alive intellectually.

JC: Free is always good, but freeware often progresses at the developer's pace and you can't do anything about it. Although I don't get much monetarily from making free software, accomplishing something I thought I couldn't do is always rewarding. Getting compliments for my work always boosts my morale and is really the main reason why I still do what I do.

CD: Freeware is a good thing. Especially in the area of ECU development, where no tools or software pre-exist. It is very helpful to freely share the few that we have written. Without this, we would be still some years back.

JP: I love the idea of freeware. Something as important as engine management shouldn't be left to the rich boys only. I feel we offer stable, feature-filled applications that everyone can use. If you want to use a commercial app, that's cool. But before dropping that $400-$1,200, see what's out there and I'm sure you'll be impressed.

CM: Freeware is a good thing. From everything I've seen, it's software that was written by the people for the people. I wrote some freeware several years back for datalogging on the GM OBD-I vehicles, and that was the first of its kind at the time. Taking money for a product, either hardware or software, is a double-edged sword. On one hand, it can make it worth your while in terms of continuing support. On the other hand, you become beholden and the most important element of freeware-freedom-is lost.

HT: Do you have any suggestions for somebody who is just getting into the PGMFI scene?

DB: Read. Read some more. Read even more than that. Try it. Break it. Fix it. Try again.

JC: For people just getting into the PGMFI scene, it's always best to know the history of the whole movement. Expectations can often get really high and when something doesn't come out the way you thought it would, you'll easily be disappointed. But if you knew what it took to get to this point, you'd be amazed at how such things are even possible with the stock ECU.

CD: Read a lot. If you want to tune your car, use one of the editors, then read and ask in their respective forums. If you want to dig deeper, read the development forums and try to catch up.

JP: Take your time, research and be proactive about learning. A lot times people mistake our giving of information and software for spoon-feeding. We won't spoon-feed anyone. If you sincerely want to learn, grab a cup of coffee, a nice chair and a notepad, because once you get into it, expect to have many sleepless nights.

CM: If you're just getting into the DIY PGMFI scene, then you're fortunate. Much of the groundwork has already been laid, so you can get right to it. Do a lot of reading on the Internet. Read through the message forums and retrace the steps of those that have gone before you. Don't be afraid. It's not that tough. You'll have to do some research, but in the end you save some money. More importantly, you learn from the effort. And even more importantly, you can help teach the next guy!

We could fill an entire issue or more on DIY ECU tuning-there is that much to cover. But we'll show you the basics here. Chipping the ECU is the first step to tuning a car on your own. We used the berkit from to chip our P28 ECU, which includes the parts you need to use the ROM's written memory using PGMFI software. The kit includes:

  • (1) 28-pin quick-release zif socket
  • (2) 0.1uF ceramic disk capacitors
  • (1) 1.1k ohm resistor
  • (1) 28-pin dip socket
  • (1) jumper wire

    Now that our ECU is chipped, we're ready to start tuning. First we need to hook up our wideband O2 sensor to the car. We got our wideband from Innovate Motorsports. The LM1 kit came with everything we needed to effectively wideband tune our Project EJ Civic. While we are not going to get into the tuning process this time, we'll explain how to install and set up the wideband for use.


  • air/fuel ratio: the ratio between air and fuel entering engine
  • . BIN file: a binary file. It is a file filled with 8-bit binary data
  • datalogging: recording the conditions of a running engine
  • dual tables: fuel and timing maps for low cam and high cam on the same ROM. Usually used with VTEC motors
  • ECU: Engine Control Unit, a computer that controls a car engine
  • EEPROM: Electronically Erasable Programmable ROM; chip. (IE AT29c256)
  • OBD-0: the first unofficial generation of Honda engine electronics ('88 to '91)
  • OBD-I: The second unofficial generation of Honda engine electronics ('92 to '95)
  • ROM: Read-Only Memory
  • ROM burner: a device that programs ("burns") chips
  • ROM emulator: a device that functions like a ROM but allows changes in real-time (i.e. Moates' Ostrich)
  • speed density: the type of engine management used in Honda ECUs (n=PV/RT)
  • volumetric efficiency: a comparison of the volume of air/fuel mixture drawn into cylinder vs. the volume of the cylinder itself
  • wideband 02: a device to measure a (relatively) broad range of air fuel ratios

    PGMFI Grassroots Engine Management
    Boomslang Fabrication
    Turbo Edit
    Innovate Motorsports
    5 Jenner, Ste. 100
    CA  92618
    618 Carriage Way
    Dept GMHTP
    Baton Rouge
    LA  70808
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