The links to other sites will probably cover a great deal more than anything I can write about currently. This page should help explain some of the basics for now and any other questions I find from those just starting out with any of this.

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Q: What is a bin file?

A: A binary file with the data and execution code for your computer, listed by 4 letters and 4 numbers. Those 4 letter codes are called BCC or Broad Cast Codes. They are the identifier for the code on that particular chip. If you look up your vehicle and find that a few different bins match, there might be a difference between the 2. It is best to get the letters off the chip in your car and looking in the download area to see if we have it already. For starting out though, just grab one and examine it.

Q: What is the code mask? What Is A1 DF 88 6D?

A: Each bin has a layout for that chip. The code mask is like a key, telling you where the variables and tables are. While a 1990 and a 1991 3.1 may have very little changed in the code, the layout for each will be different. This means you will want a definition file for your chip to put the code into terms you can deal with.

Q: Ok, then what is a Definition File?

A: This is the map for your code. It will translate those hex values into decimal values and also explain what they go to. You need a program however to use a definition file.

Q: What programs do I need?

A: I use winbin and TunerPro to edit the bin files. TunerPro is more advanced and has much better capabilities than winbin and can use the winbin .ecu files.

Q: What does BLM and INT mean/do?

A: BLM and INT, which is long term and short term respectively. Both should be as close to 128 as possible (BLM more so). Ill try to explain it, but you can read more about it (in terms of the older computers and F bodies at that) here.

Block Learn Multiplier is what your fuel is based on, using the hard coded fuel tables in your computer as a guideline. If you need more fuel than the computer is programmed for, the BLM will increase. If you need less, it decreases.

The Integrator is how the BLM changes effectively. BLM doesn't jump around instantly based on changing condition, but the INT does. It uses the O2 feedback to either increase fuel or decrease fuel compared to the hard coded fuel tables. If you are constantly needing more fuel, the BLM will increase and the INT will slowly decrease. From a tuning perspective, I add both BLM and INT and divide by 2 to get the real fuel needs at a particular point.

Things you should look at, an INT that is jumping higher and lower than 128 at different RPM and load (MAF, MAP, whatever setup your car has). If it is going all over the place, a reprogram would be highly advised. Reason being consistency. The fuel at WOT does not use the O2 sensor is solely based on the BLM at the time you go WOT (called power enrichment or PE in the computer).

Links

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Until I have time to go through a detailed list for this FAQ, you should check out the following links for information.
Thirdgen.org
Diy-efi.org