Just bought an 88. It has a hypertech chip in it. I'm trying to program a stock bin to a new chip, but the only file that my ecu recognizes is if I program the hypertech bin to the new chip. All other bin files leave my car in limp mode. Anyone know if I need to change the mecal?...does hypertech use their own, "special" memcals? Thanks!

 

Which type of eprom is on the memcal?

Is it a 27C128 or 27C256?

If its a 27C256 eprom you will need to stack the stock bins to double the size or offset the start of programming to 4000.

What is the size of the hypertech bin file? 16384 or 32768 bytes? That should offer a clue as to which eprom is in use, if you can't make it out on the chip itself.

 

The stock eprom (which I don't have) is supposed to be a 27c128 ABTS. I can't find that excact bin file anywhere. The Hypertech chip is a 27c256. I've succesfully programed the hypertech bin file on another 27c256, and on a 27128 chip. It's just trying to program a stock bin I've downloaded to a chip that I'm having trouble with. I've tried several different bins...ARAP, ABTR, ABTP, etc. That's why I'm wondering if the whole memcal was changed and won't work with any file except the hypertech one.

 

With a 27C256, you need to either stack a stock bin (16k) to create a 32k file with a stacking utility or hex editor, or simply program the 16k file onto the 27c256 starting at address 4000 instead of 0000.

Your programmer should permit options for start and end addresses.

The hypertech bin is probably already a stacked bin, which would explain why it works with the 27C256.

I've stacked bins successfully for 27C256 eproms, but I have never tried programming one with the starting address offset by 4000. Both methods should work.

Normally I use 27C128 eproms since that's what I have on-hand and its nice not having to bother with stacking bins, etc.

Here's a listing of 88 bccs from chevythunder.com if it helps. I use an ABTR based bin with my 4+3.

1988 350 (5.7L) "F" body Camaro-Firebird-Trans Am "Y" body Corvette

Prom BCC Prom Code Scan ID Trans Gear Ratio Emissions Body
HCY 9539 1571 4 sp man 3.07 Fed Y
HCZ 4423 1581 4 sp man 3.07 Fed Y
HDA 4427 1591 Auto 2.59 Fed Y
HDB 4431 1601 Auto 3.07 Japan exp Y
HDC 4435 1611 4 spd man 3.07 Fed Y
HDD 4439 1621 4 sp man 3.07 N/A Y
HDF 4443 1631 Auto 2.73/3.07 Japan exp Y
HDJ 4457 1651 Auto 3.07 export Y
HDK 4461 1661 4 sp man 3.07 euro exp Y
AKXX 3269 4731 Auto 3.27 Fed F
AKXY 3287 4741 Auto 3.27 Fed F
AKXZ 3294 4751 Auto 3.27 Fed F
ABTP 4757 7841 4 sp man 3.07 Fed Y
ABTR 4763 7851 4 sp man 3.07 Fed Y
ABTS 4767 7861 Auto 2.59 Fed Y
ABTT 4773 7871 Auto 3.07 Fed Y
ABTU 4802 7881 4 sp man 3.07 Fed Y
ABTW 4806 7891 4 sp man 3.07 Fed Y
ABYA 5400 8461 Auto 2.77 Fed F
ACKY 9968 9531 Auto 2.73/3.07 Fed Y

 

Thanks for the codes. I understand about starting at hex 4000 and stacking. I've tried both ways. The hypertech 27c256 is started at hex4000. I can sucessfully program the hypertech bin file on both a 256 and 128 chip. The problem is getting any other bin to work. That's why I'm wondering if the memcal is from hypertech....and will only work with a hypertech chip.

 

Maybe something screwy about the Hypertech memcal hardware or encryption scheme. Strange.

Can you read the hypertech bin file with an editor and 32B mask? I have at least 1 hypertech bin from an 87 f-body, that I was able to read and edit normally.

What don't you like about the Hypertech for your car?

It is likely only a lightly reprogrammed stock bin, anyway (fan on/off temps/idle rpm/converter lock up speed changes, etc.).

Unless it is somehow encrypted, or a unique mask??, you should be able to diff it against a stock bin to see the changes and you should also be able to edit it to correct whatever you want with any of the editors out there.

If that's the only bin you have that's working, try and tune it to meet your needs, until you can score another memcal to work with.

Good luck.

 

Thanks for your help. Yeah, I've tried several masks to read the hypertech chip with no luck. Guess I get another memcal.
BTW, problems with the hypertech: Idles at 800 in drive, shifs at 4300rpm at wot, fans turn on at 180 so their always on, and seams to have a lack of power....can't spin tires from a standstill!!