Programming & Understanding Chips.


motorhead mike
Sep 9, 2001
Where can I learn too?

I keep "reading" tonnes of stuff I just don't understand... is there a place (site, book) to become more educated on chips and how they relate to our cars?

A few questions.

wilkinshc, thanks for extending the offer.

I guess that it would be best to start with the most basic terms and abbreviations.

Add yours here :)

So at least I can interpret what I am seeing.

What are some of the most basic terms used to identify ECM functions?

[Start loop]
I will admitt that I am very green at automotive programming.
I do have some experience with Basic 7 QBasic from highschool... and I have "hacked" a few video games in my day... but that is about it. I feel that I am a quick learner... so I shouldn't be asking too many questions twice.
[End loop] :D

please feed me what you can... as I am a long way from DFI,
More important than progamming, you need to understand how an engine works, how timing and fuel play their roles, what adding or removing any ingredient does and what the benefits or what damage can be done by your changes or mistakes.

If you really wanna learn the fundamentals, a guy named Bruce Plecan wrote a really informative document. Its up on gm_ecm's ftp site but its address escapes me.

There is a couple docs on their website, both written by Bruce. One is "Bruces Tuning Tips" and is at:

The other very good resource, also by Bruce is:

Which goes over the functions of the various tables and calculations made by the GM computers. That paper is written more for a different ECM, but much of the INFO can be applied here.

Once you fully understand all consequences or your changes, its then time to worry about doing the programming. I am just a tinkerer. I cannot program, I just have (I think anyway) a good idea what it takes to make a car run well. If you can do both, like the Lubrants and the Carters of the world, you'll do well :)

Just realize it will be a learning experience, and be prepared to take things apart should you do something wrong :p

I will read this stuff.

I knew Bruce back when he was on the mailing list. In fact I have some of his "just after completion" pictures of his GN on my website.

He really is a bright guy. I learned a lot in his time on that list.

He is on this board, right? "Bruce" is his user name, I believe?

SBCs & Turbo 231s are apples & oranges.

I know how to tune an apple :D
Not really, only difference when you get down to it is one has 8 holes, the other 6. If you can successfully tune one, you can do the other.

Looks like you got a handle on it. Good luck. If I can help, let me know.
Get the chip docs off and things will be slightly clearer... you can also FTP from the same sight the "Tweaker" program. Not real powerful but GRAPHICAL and that would help you a lot!!! Mostf of the changes you would want/need are there unless you change injectors or some other bigger item. By the time you need more features you will be ready for them.


What I mean is start with something simple and easy to verify such as TCC lockup. Burn it and try it. Doing it this way makes sure that if the car wont idle you may assume the burn process is likely to blame. Using a graphical program like Tweaker ensures you dont make a typo when ONLY adj TCC type settings.... and as a bonus it will calc the checksum for you.

Finally if you havent, I suggest you go ahead and purchase a chip from your fav vendor. Most wont care if you plan to alter it for YOUR purposes, especially if you tell them up front. This gives you a stronger base from which to work and is doubly benificial if making major mods at the same time.


Bob at BM Computer Source sell software or a package setup to burn chips for the TR cars. I bought this setup and didn't know where to start either. Infact I would not and still don't know how to hack into a program. You can download the software for free and look at the tables. Jim Testa is a wealth of knowledge and has help me from time to time. I feel pretty comfortable burning a chip now and even helped others burn a thumbwheel. There is about 5 tables that I change mostly "ecm constants" it changes injector flow rate, fan off mph, fan on temp, boost scaler for 3rd & 4th, torque converter lockup 3rd & 4th, and a couple of others; "pe vs rpm" helps adjust fuel curve ( I also use the injector flow rate also); "boost vs rpm" sets your boost level: "knock attack rate" adjust how much timing comes out when knock is sensed: "knock recovery rate" adjust how fast it puts the timing back in. These are the ones I work with mostly and a good place to start. I would recommend it you start burning chip make small adjustments until you find out what difference those adjustments make.
The software Bob sells also has a compare option which is useful in learning. I took the chips I had and compare them to each other to see what the changes were and made notes to what I liked about them to adjust my own chip. Plus after recording Direct Scan runs I can go back into the chip and adjust the tables for my car and my combo. I don't know how to do patches yet like locking the WOT blm to 128, or fast update code but have made big improvements in preformance on my car.

Re: Thanks.

Originally posted by Mr. T

I knew Bruce back when he was on the mailing list. In fact I have some of his "just after completion" pictures of his GN on my website.
He is on this board, right? "Bruce" is his user name, I believe?
SBCs & Turbo 231s are apples & oranges.
I know how to tune an apple :D

I lurk atta few places <g>..
GN looks about the same from the outside still.
It's getting to be an animal

SBC, Buick Turbo, Viper, Porsche, once you get the basics down they are about the same.

Trouble is the mind likes to play tricks on logical thinking. More timing and more fuel don't always mean faster.

Notes, notes and more notes save lots of time
wilkinshc & bruce

Thanks for the advice guys. Noted!

Bruce, good to hear from you. I have been meaning to write you an email since I picked up the T. I have been waiting to jump into one of these cars for years... money now allows it.

I will never forget those first test-drive posts of "the Black Car".

You were one excited guy :) So was I :D

I still have your last post to the G-body list saved... it has been almost a year!

I hope that all is well...

Before I get into burning stuff... I have to get a resto done on the T... I hope to be getting more "student assistance" to aid in the learning process, if you catch my drift ;)

Reds 93 chip for stock injectors coming... I guess this is where I can start to reference & compare,