LT1 $EE Read .bin Flash different from .bin Flashed??

[dave w]

I've just benched flashed my first LT1 PCM. I've noticed some differences in the .bin file I read from the LT1 PCM vs. the .bin file I flashed. I'm using the compare tool in TunerPro. All the differences compare tool finds are "undefined" address. Is this normal with the LT1 PCM's? Are the "undefined address" related to Check Sum? Maybe the differences are with VIN information?

My other flash experience has been with both the LS1a & LS1b PCM's, I get no differences comparing the flashed vs. read file. I admit I'm not using TunerPro with the LS1a & LS1b PCM's.

dave w

[steveo]

did you read the bin, modify it, then load it?

or did you start from scratch with a bin you downloaded from somewhere

yes those are a lot of differences, and no they aren't checksum or vin related

they're probably routines such as you'd see from comparing a 94 to a 95 bin, or a vette bin to an f-body bin, but those usually have a ton of known constants that are different as well?

[EagleMark]

Checksum is only a few bytes, so is VIN... you've got 587 bytes difference? Me thinks something bad happened? Did you try and reflash first read back in? Also need to turn off Key On power for 30 seconds before removing Batt power for VIN change.

[dave w]

The sequence I did using an OBD1 bench flash setup. This is not the first bench flash setup I've done. Seemed to read fine. Attached is the original .bin I read. Laptop is WinXP OS.
1. Read the original .bin file.
2. Modified the original .bin file. (note I switched manual trans using TunerCats Software)
3. Used TunerCats to flash the PCM with the modified .bin. On the read from the TunerCat flash I noticed the BLM 128 lock had differences plus the "undefined" differences.
4. Reflashed the modified .bin file with WinFlash (free trial version) and read again, the BLM 128 lock differences were unaffected with WinFlash but the "undefined" differences were still there.

Plan going forward, to troubleshoot.

1. Reflash (WinFlash) the original read .bin into the PCM. Check the original read vs. the reflashed original read.

2. If need be, I'll use one of the $EE .bin files posted here at gearhead-efi.com and see what happens.

3. Theory I'm thinking, the flash erases the .bin then a new .bin is programmed. What gets flashed into PCM should read back exactly what was flashed in.

It's a used PCM, so maybe I started with a bad .bin / PCM?

dave w

****Added more read files bench flashing setup ****

[steveo]

yes that's possible

thing is you should get checksum err if the flash was bad...

if you write a bin then read it, it should be bit for bit identical. if not, something is screwy.

[dave w]

yes that's possible

thing is you should get checksum err if the flash was bad...

if you write a bin then read it, it should be bit for bit identical. if not, something is screwy.

I just flashed (WinFlash), then read (WinFlash) BKFS ( http://www.gearhead-efi.com/gearhead...16181333%20EE/ ). Something must be screwy!

Get this ... the first time I read BKFS after flashing BKFS I got about 1200 bits difference "undefined only" between the file I downloaded and the file I read. So I read the PCM again, after removing power for a few minutes, that time I got about 1600 bits difference "undefined only" between the file I downloaded and the file I read a second time. It's very screwy, because only "undefined" bits are different not the defined parameters. It's very odd, the differences are not "FF" or "00" they have a value like something was re-wrote.

I can try a different laptop computer to flash / read with. The bench flash setup should be solid, I'm thinking it would be impossible to flash / read without an error if the bench setup was wired wrong? Maybe move the data line to Blue 30 instead of Blue 29, but I don't see that making a difference?

I'm using a USB ALDL cable from http://www.aldlcable.com/ ... the jumper is across the top two pins. I've data logged both 160 / 8192 baud ECM / PCM with this same cable. WinFlash shows it's communicating with with the LT1 PCM, then the flash / read process starts at Zero and finishes @100%. No error message. The bench batteries (a bank of 15 batteries rated 7 amp / hr wired in parallel) are measuring 12.6 VDC.

I'm thinking I need a different PCM to flash / read and see if I get the expected bit for bit flash / read. Before I get another PCM I'll try using a different laptop computer and swap the serial data pins.

dave w

[EagleMark]

I'm using a USB ALDL cable from http://www.aldlcable.com/ ... the jumper is across the top two pins. I've data logged both 160 / 8192 baud ECM / PCM with this same cable. WinFlash shows it's communicating with with the LT1 PCM, then the flash / read process starts at Zero and finishes @100%. No error message. The bench batteries (a bank of 15 batteries rated 7 amp / hr wired in parallel) are measuring 12.6 VDC.

dave w

Jumper across Bottom towards USB port is normal same as if no jumper is used. Not sure what top does. Try with no jumper!