So I just got a programmer and tried my first prom.

The car is a '89 to which I am putting a 350 with a tpi and harness from a 305 '86. The engine was running on the original 305 prom (not driven as the car is not drivable yet)

So my first burn was a stock '89 350 bin on a 27c256 chip. I think I got the bin doubled up on the larger chip though I can't figure out how to load only half the bin into tunerpro to verify it. When I read the chip with the programmer on the 27c128 setting I get a 16k bin that matches the original.

When I put this new chip into the car I got nothing. It wouldn't run at all. I went back to the old 305 chip and it ran, but not like before. I'm sure it was in limp mode (the fan was coming on). Then I read the codes and it gave me a 51, problem with memcal. I think I was having connection problems with the zif socket I put on the memcal though even when I took the zif off and put the stock chip directly onto the memcal it was still in limp. I don't know if I messed up my ecu with the burnt prom or bad zif connection. The factory prom still reads fine on my programmer.

I am still struggling with the bin definition thing. I now know that the original chip has a 32 xdf and the 89 I burnt is a 6e xdf. Must I stick to the 32 xdf?

Thanks,

Mike

 

If you want to load a 16K bin (MAF) on a 32K chip (27C256), you must load it on the "upper" half. People either use a 16K address offset (if their burn & software can do it). Else, they "double up" the bin make one large 32K bin out of 2 - 16K bins.

You can do this with a DOS Command similar to:

32k.bin=16k.bin+16k.bin

Then you load 32k.bin onto your burner's buffer for burning.

 

So after some more searching and reading I now understand it is okay, and many say desirable to replace a $32 bin with the 6e, minus the cold start injector.

So am I correct if I say the prom contains both the data for the car (the part we all modify), and the program to interpret the data (the mask or definition) ?

Now, these xdf files, I understand these are files for us to interpret the data. Now are these files that someone made for their own use, then was gracious enough to share with the rest of us, or, are these actual GM files?

Thanks,

Mike

 

if i understand your question right, the mask is whats on the chip, i.e. 32 or 6E, & requires the right definition file to interpret the data on the chip.

my understanding is in the early days the definition files were done by the DIY community with some help from someone at GM. sense then others have added the the definition files.
things have progressed greatly in the last few years, the early programs were hard to use & from what i understand most only worked only in DOS, a good example of the advancement of the tuning programs is TunerPro.

if you haven't read this thread already, you may find it useful,
https://www.thirdgen.org/forums/diy-...tion-file.html
its an example of DIY at work.

 

The truth is, GM used a number of different calibrations ($6E, $32, $32B) where used with the '165 ECM. They used even more with the SD '730 ECM.

You can think of this as running "Windows 3.1, Windows 95 & Windows 98" on the same computer.

However, as the programming (and data) in each calibrations is different, you need a different "XDF" (if using TunerPro) to modify the various data portions within the bins.