pcmhacking.net

Hi guys,

I'm new here on this forum, or at least new in posting something.

My current project involves a Delco BNHJ for a X16XEL engine in an Opel Astra (red/yellow connector with the exchangeble 27c512 eprom.

I'm currently defining some maps like rev limiter and basic fuel and ignition maps.

But why I am posting is, I like to know how its done regarding to checksuming.

For example when changing the rev limiter from 6750rpm to 4000rpm the difference between files in Hex is 4b.

Then the compensation for this change happens on location 3807.
Why on 3807 you say? I have a stock file and a file where the rev is changed. In HxD I compared the files against each other.


This can be done by hand. But when I change something in a larger table manual correcting gets a little tricky.

Does some of you guys have a solution?

I can post some files or maps tomorrow, Im typing this from my phone

It probably wont be hard to create an xdf for tunerpro that will sum the correct areas and update the checksum. Just need some samples to look at it. Ideally you'd put the sum settings in the same same XDF as your using for tuning and post it up to help others also. If you post up your XDF and the example bins i'll see if I can add the checksum for you.

Hi Antus,

I'm working some things out in free winols.

In the attachment 2 files, one stock. and one changed by some guy i dont know, both files confirmed working.

When i'm done searching and defining maps I will post my mappack here.
But first I want to find out the checksumming and how it works. like in detail.

How does it work in a nutshell?
Something like: When the changed Byte is for example 2b higher, you compensate 2b elsewhere in the file?

I'd like to know, where the checksum locations are..!

kind regards

Checksum location is at 3806 (E8 2B) Calculation is from 3808 and FFFF

kojab wrote:Checksum location is at 3806 (E8 2B) Calculation is from 3808 and FFFF

Hi Kojab,

Thanks for your answer, is that the checksum location for the whole file or just for some area within the file?

Not for the whole file, just for the area between 3808 and FFFF (the end of the bin file)

Guys for the sake of future readers.
I think after this post a lock can be placed on the topic, for my question has been answered.

For the Opel Astra 1600 Delco Multec S BNLA, BNHJ, BPUK, BRNZ the checksum location mentioned above is confirmed. (other computer types I do not have the ori file)
Edit: Also confirmed on Opel Tigra 1400 BRNW file

I do future checksum correction manually with HxD Hex editor.

Instructions:
- Open file
- Ctrl + E
Start offset: 3808
End offset: FFFF
Press Ok

- Press Analysis
- Press Checksums
- Select Checksums-16
- Press OK
- Note the 4 character Hex written under the column "Checksums"
-Ctrl + G
Offset: 3806
Press Ok

- And check or correct your Checksum

The mappack/xdf is nowhere near finished, so I can't post it yet, when I'm done I will post it here.

Ok, so far we dont have any threads like this stickied, generally we'd have a thread of xdf or adx stickied, but since we dont yet have any euro stickies we might as well start somewhere - this thread. Any other unique or commonly required info we can also start to sticky, but down the track will probably need to start grouping information and sorting it a bit. Thanks for the confirmation.