Okay here goes,have tried unsuccessfully to burn the atmel29c256,btw it burned to the point that I can go back and read it.Tried a 27c128(can read it also)but check engine light comes on immediately(runs sh***y)memcal is from an 86 corvette(165 ecm) and runs fine in it.tried in a 86 z28 and runs also.fwiw
the prom i.d. changed after modifying chip to my likings.Is this a relevant factor? Chip has never been removed(27c128)so I know it is not a grounding issue.I can always go back to the tpis chip and runs fine.This has been tried in 2 different p.p. and the same results.I've been at this for about 4 months and getting know where fast!!any help/advice or insights would be greatly appreciated.this is causing insanity!!!! thanks in advance

 

OK, I'll take a shot at it. I am pretty inexperienced, but it sounds like something basic is wrong. If you use a 256K chip in a 165 ECM you either need to start burning at a different address, or "double up" on the code. Check the Properties of the .bin file you're burning and size should be exactly 32K. If it's 16K, go into DOS and copy your bin onto itself:

c:\ copy /b file.bin+file.bin newfile.bin

where file.bin is the 16K .bin file. Newfile.bin will now be 32K in size.

Not sure why the 128 chip doesn't run right in the 165 ECM; if it's running lousy, sounds like you're in "limp home" mode. The prom ID may be a hint: I've never noticed if mine change or not. How are you modifying .bin files? Also, don't understand what you mean by "This has been tried in 2 different p.p. ".

I think you need to give us more detail and focus on what you're trying to accomplish i.e. is it to use the 29c256?

good luck

 

Glenn suggested this to me in my post 'Chips not burning correctly' a few weeks ago:

Burn the AT29C256 chip in PP like you normally would, then read it as a 27C128 chip. Compare this buffer to the .bin file you created, they should be the same.

We need a bit more info though, like what program are you using to create the .bin file, and what kind of changes are you making?

To troubleshoot, I would try reading the stock bin and burning it onto the 29C256 chip. If you can't get that to work, let us know.

My promid changes with different bins, I think it's related to the checksum..