I’m at a point with my 86 GT that I need to make some slight changes to the injector pulsewith tables on the stock V6 ECM. I know what HEX values and lines I need to look at, but before I dive into this I have a few questions.

1. I know that the 2732 EPROM is preaty common, but all the EPROM burners I’ve seen only list the 2764. Will a 2732 still work in most of these programmers? I am mostly looking at the Willem EPROM Programmers.
2. Is there a direct replacement EEPROM for the 2732? I would be a pain to have to UV erase every time I need to rewrite on the chip.
3. I have an electronics degree, but I haven’t played with CMOS style chips for a long time, any suggestions are welcome.

Thanks in advance
Don

[This message has been edited by HitesFiero (edited 10-24-2006).]

Bump, anybody?

You can use a 2764 Eprom in place of a 2732.
It is twice the memory size so for it to work properly you would have to do
one of two things:

copy the file into the eprom twice to fill up the available space
(when I say twice, I mean your file plus empty space to equal one half the size
of the available memory and then put that same file in again)

OR

Know the start address of the upper half of the memory
and just burn your file into that upper portion only

The first method is the easier of the two, you just have to have your file formatted
correctly.

Your programmer software will allow you to copy the file twice and then save it so
you will have a double sized file.

Hope this is of help

2732's are a PITA. they are differrent than the 2764, but that also depends on the suffix of the chip. there were I think 3 or 4 differrent versions of the 2732, each used a differrent programming algorithm and voltage. I'll see if I can hunt up an onloine reference. I would be sure that if you get a burner that it lists 2732 in the list of supported chips. the problem is that the 2732 can use 21 or 25 vpp whereas most higher chips are 5 or 12v units.

I also do not believe there is a EEprom replacement for the 2732, but I have not checked in years......
closest would be a 28c64 I think, and you would need to adapt it and use the lower or upper half. would be easy to do an address line switch, so you could just swap roms on the fly.

the right willem programmer will program a 2732a or 27c32 I reccomend getting the 27c32 as they program at 12 volts instead of 21 volts.

2764's have a different pinout due to having more pins, you will have to do some modifications or build an adapter.

I have no problems with 27c32b chips. I get them for $4.60 on ebay all the time and they work well, jameco.com also carries them.

also not a pain to uv erase. I purchased a replacement uv eraser from ebay for 9.00 and it erases eeproms in 12 minutes, get 3-4 eproms and never be inconvienced.

[This message has been edited by timgray (edited 10-24-2006).]

Is ths stock EPROM a 2732a or a 27c32?

stock is 2732a but a 2732,2732a,2732b,27c32,27c32a, and 27c32b are all 100% identical after programming and in read mode. the only difference is in programming, they all read the same way. the c denotes CMOS low power consumption while everything else is Nmos and higher power draw plus older tech. if you look at a old 2732 and a 27c32b you notice the die inside is significantly smaller because of technology changes from 1983 to 1995.

Thanks for all the replies! You guys have given me the info I needed! I love this forum, +'s for all!

Can anybody recoment a BIN editor that will work well with the BINs I pull off with the Willem unit?

http://fp.enter.net/~rockcrawl/EPROM.html

freebie for Fiero GT 86-88. honestly you need to buy tunercat and a def file to get further along.

quote Originally posted by timgray: ...honestly you need to buy tunercat and a def file to get further along.

That would be my recommendation, too.

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Raydar
88 4.9 Formula IMSA Fasback..........................88 3.4 coupe................................................

Read Nealz Nuze! Praise the Lowered!

I would love to find out what else out there will support our cars and make it easier for advanced tuning... Tunercat is pretty low price compared to some of the other stuff out there, but I cant find anything else that is in the pro level that supports our cars.

Honestly the more you dig into the ECM the more it all makes sense, and the easier it gets.

The only thing that would make it easier is a live tuning system, but that requires you to completely swap out the ECM to an aftermarket.

On a side note, I would love to find a modern GM ecm that is easy to reprogram to see if we could make a cheaper general purpose replacement ECM that allows more advanced tuning than the current one does... but honestly a megasquirt would probably be cheaper wfter you get to that point.

I found a simple Bin/Hex editor and I have already made my changes. I was forutunate enough to allready know which lines of code to modifiy.
For the record, my reason for all of this is to make 19lb injectors work in place of the stock 14.3 units on a mostly stock 2.8. I dialed back the base fuel pulse. My calcultaions where spot on so i think it should work very well.

Well I’m not quite there yet, I have my modified bin saved but now I’m having trouble getting my Willam unit to program my new 27c32b. I’ll have a screen shot up later. Tim, what kind of reader/programmer do you have?

I have a old Heathkit eprom programmer and a newer Willem version 4.5 you have to modify older willem programmers to handle the 2732/27c32/27c32b is yours the newer type with pushbuttons to select programming voltages and eprom type? if so a simple jumper in the zif socket to jumper your top right pin up 2 more pins does the trick.

let me look at my documents and I'll tell you mine wants...

try this...


to read or write 2732, 2732a or 27c32 chips insert the chip as normal in the programmer, set up the programming software as normal, now insert a wire jumper from the top right pin of the eprom to the socket point up 2 positions from that.

in other words, jumper pin 24 on the eprom to a blank pin position 2 spots up from 24. This will give the chip power so that you can read and program it normally. the 27c32b should not need any voltage changes, the programmer will do the job it's self.

If you need more details please feel free to ask to clairify before you smoke your programmer/eprom

[This message has been edited by timgray (edited 11-03-2006).]

This is the exact one that it have.
http://cgi.ebay.com/Dual-Power-Universal-Willem-EPROM-Programmer-2732_W0QQitemZ230023467091QQihZ013QQcategoryZ4661QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

The frustrating thing is that I can read just fine!

I'll try the jumper Tim

Yeah, that is an older design... the newer ones have a row of 11 led's across the top and two buttons to override the software and set programming language and modes, you cant adjust your voltages easily on yours.. try the jumper and see if it programs for you.

when you read a new blank one it shows all FF FF FF FF FF FF in all memory locations right?

if your programmer is not setting it up right, try setting it for a 27c64 with the jumper and it will fail programming. but then read the chip and see if the first 32K made it into the chip.

do you have any different eproms to verify that the programmer is working?

Well the jumper did not work, so I got my meter out. The 27c32 takes between 12.5 and 12.75 volts a Vpp to flash. When I set the program to flash i got just that at pin 20. This is driving me nuts!

Offset lines FA through FF are 00 at all points this is how it came off the origional EPROM, do I need to change this before writing?

You want to write to the first 32K of the chip so no offset is needed. the second 32K does not even exist so when that fails it should be fine.

take the bin as you read it and try to flash it with no offset on a different eprom setting. remember, the difference is only address space and extra pins for it to be accessed.

quote Originally posted by timgray: The only thing that would make it easier is a live tuning system, but that requires you to completely swap out the ECM to an aftermarket.

Not quite grasshopper!

What I've done is pulled apart a stock ECM and installed a ZIF socket in place of the ... bizzare-whatever-it-is ... socket for the EPROM.
Then I use a Pocket Romulator ( http://secure.transtronics.com/EPROM%20Emulator.html ) attached to my lappy running tunercat. Presto! On-the-fly programming!

Not quite as nice an interface as my Megasquirt (let's NOT start that debate again ok?!) but it's totally usable.

When I get a profile I'm happy with, I just burn the BIN to a chip, and stick it in. Or I just leave the Romulator dangling out and keep driving until I accidentally knock it out and the car dies and I get pissed and burn a chip and.... well... you get the idea....

Oh - whatever you do - DON'T let your laptop go into standby/hibernate/etc mode when you've got tunercat going "live"!!!!!!!!!!!!!!!!!!!!
The Romulator will erase itself, and the car will go into a somewhat 'limp home' mode!

Of course, all you have to do is fire the machine back up and do a quick reprogram of the romulator - but try explaining all of that.... to the guy at the emissions test station who's test running your car on the dyno at the time! OOPS!!!!!

quote Originally posted by watts: Not quite grasshopper! What I've done is pulled apart a stock ECM and installed a ZIF socket in place of the ... bizzare-whatever-it-is ... socket for the EPROM. Then I use a Pocket Romulator ( http://secure.transtronics.com/EPROM%20Emulator.html ) attached to my lappy running tunercat. Presto! On-the-fly programming! Not quite as nice an interface as my Megasquirt (let's NOT start that debate again ok?!) but it's totally usable. When I get a profile I'm happy with, I just burn the BIN to a chip, and stick it in. Or I just leave the Romulator dangling out and keep driving until I accidentally knock it out and the car dies and I get pissed and burn a chip and.... well... you get the idea.... Oh - whatever you do - DON'T let your laptop go into standby/hibernate/etc mode when you've got tunercat going "live"!!!!!!!!!!!!!!!!!!!! The Romulator will erase itself, and the car will go into a somewhat 'limp home' mode! Of course, all you have to do is fire the machine back up and do a quick reprogram of the romulator - but try explaining all of that.... to the guy at the emissions test station who's test running your car on the dyno at the time! OOPS!!!!!

[QUOTE]Originally posted by watts:

a lot of ppl rumulate till tuned then burn a chip...
or burn a multi chip (8 to 16 diff tunes) for all occasions and toggle or switch between .bins

http://www.moates.net/product_info.php?cPath=51&products_id=48

http://www.moates.net/product_info.php?cPath=26&products_id=39

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[img]http://img423.imageshack.us/img423/1603/streetbacksmr1md.jpgGT just waiting for the conversion[/img]

84 Fiero Turbo Vortec 4300 Phantom GT
L35 block, Syclone Intake and ECM
T31 turbine with T04B S3 compressor
super T61 waiting for next winter
www.cardomain.com/id/vortecfiero
Murphy's Constant Matter will be damaged in direct proportion to its value
Murphy's Law of Thermodynamics Things get worse under pressure.
Arthur C. Clarke "Any significantly advanced technology is indistinguishable from magic"

Well I got the writing problem figured out! My two spare 27c32 have a write voltage of 12.75V, my Willem programmer was set at 12.5. I was aware of this but I assumed that .25 volts would not make a difference boy was I wrong! I would write the first bit then error out. So out of sheer frustration I set the unit at 25V figuring that if I killed one of my EPROMs I would only be out $5. Well at that voltage it worked like a charm. Unfortunately I was only writing test code and not my modified BIN, and when I went to UV erase my two chips my second hand eraser decided to fry itself. I have a friendly acquaintance at a local electronics repair shop that will erase them for me. So after that I should be able to report on how well my mod has worked.
Until later.

a cheaters Eprom eraser is a daylight color 60 watt Compact flouresent lamp. take a tye wrap and make a slightly snug band around the lamp and hold the chip window against the bulb and leave it on for a couple of hours....

works great for me, it has to be a daylight bluish tint though... those have lots of UV coming out of them. also bare bulb type. a cover is usually a uv filter.

That's good to know Tim, thanks! I was contemplating the use of the huge mercury vapor light in my garage, but it throws out so much heat I'm afraid that it might damage the chips.

If you have a decent eltrical suuply house around, you can get a germicidal 6" flourescent lamp that will work in one of those little battery powered portabloe single flourescent tube units. mod the unit for an adapter, put it in a box as uv is very bad for your eyes, put the chip about 1/2-1" away from the bulb, it will be erased in an hour or less.
for more details do a search on eprom eraser, there is a uk site that gives all the details.

CRAP! CRAP! CRAP! CRAP!..........Ok, I think I got it out of my system. Well I was able to write the BIN back to the EPROM and it looked identicle to stock with the exception of the changes I made. I reinstalled the chip and low and behold!?!?!?!?! I have a rapidly flashing Check Engine Light! Advise, insight, holy water? Anybody?

did you put the chip in backwards??

Ok now that you stopped throwing wrenches at me for being a smart-ass....

Read it and compare to your file to be 100% sure it was the same.

I suggest ruling out burning issues by burning a read of your stock chip onto a blank and trying it.

On the last 4 or 5 lines of code there is no real data, should these "blank" rows be populated with 00 for FF?

I dont think there is a checksum, although I never edited a prom by hand in a hex editor.

A burn of a stock read worked then? so you can rule out burner settings and technique?

I have not got to this point with my 3.4 but I thought there was a checksum and read that it will set a light if not right.
I could be wrong. I'll see if I can find that site.

Yes Tim, that is correct, I made a direct dupe of the original and it worked. I don't suppose anybody out there would be willing to take a look at my BIN if I Email it to them? I haven't driven my GT in 3 weeks and I'm going through withdrawal!

Tim, you have been a huge help to me up to this point and I appreciate it!

yes there is a checksum. if you downloaded that free gmpro fiero version, you can set the correct checksum with that. I'm running in linux right now as my xp partition is crashed, so I'm doing this from memory, but I beleive it is an option on the right side to calculate the checksum.
btw, if you get lucky, you migh only have to hit those bytes (2 I think) if the bits line up that the off ones are correct, you can just tweak those bytes. eproms as you should know turn off the bit on a burn, and you can alter bytes without a full reburn if you are lucky. (that's a real old time trick!)
btw2 here is the link to the cheap build it yourself eprom eraser:
http://www.mikeg2.freeserve.co.uk/eprom/eraser.html

Would a pooched checksum cause the supper fast blinky on my SES light?

Sweet! good to know. I never made changes outside of gmepro in a straight hex editor so I never encountered the checksum gotcha.

Dodgerunner, if you can post the site that has details like that about our proms that would be great.

Might not be a bad idea to put together a "Fiero ECM EPROM FAQ" thread about this so others will have an easier time of it.

[This message has been edited by timgray (edited 11-09-2006).]