Hi all! Working on 94 Z-28, A4.

[SweetZRag]

Hi all. Looking to expand my knowledge on OBD1. I am an Electrical Engineer and I majored in Digital Signal Processing. I am working on my 94 Z-28 and want to explore what is out there for diagnosis using the ALDL. I am very interested in finding info for the datastream definition for my car. $EE I believe. I want to learn about the design of ALDL which has been difficult due to its proprietary nature. I am hoping some info has been made available now that it is obsolete. Thought I might find what I need here.

[SweetZRag]

Really interested in software protocols as I have the interface designs. Hopefully someone has released the specs by now as I don't trust the hacked files out there.

[1project2many]

Hello,

Most of the information needed to do this found its way to the 'web years ago.

http://gearhead-efi.com/gearhead-efi/doc/Senior_Project_2007_Automotive_Diagnostic_LCD_Inte rface.pdf
http://gearhead-efi.com/gearhead-efi/def/aldl/

[steveo]

pm me your email address, i have a few documents i can send you privately that might interest you as far as the science behind this ancient serial protocol

of course the software in my sig kinda covers every aldl function in $ee so you would be reinventing the wheel ;)

[SweetZRag]

Hello,

Most of the information needed to do this found its way to the 'web years ago.

http://gearhead-efi.com/gearhead-efi/doc/Senior_Project_2007_Automotive_Diagnostic_LCD_Inte rface.pdf
http://gearhead-efi.com/gearhead-efi/def/aldl/

I have been a member of cz28 forum for years but only recently found this site. Nice to see so many people finally get into tuning. When I bought my Z 20 years ago, it was hard to come by. Only a few people knew anything about it. Looking forward to reading the links you provided and finding the info I need.

[kur4o]

http://calibra-classic.org/pages/ecu2pc1.htm#PurposeAndScope
http://calibra-classic.org/pages/ecu2pc.htm

Another interesting article.

[SweetZRag]

http://calibra-classic.org/pages/ecu2pc1.htm#PurposeAndScope
http://calibra-classic.org/pages/ecu2pc.htm

Another interesting article.

kur4o - Thanks so much for this info. This is exactly what I am looking for. I need theory so can really understand the topic. I have no intention of reinventing the tools that Steveo and others have created but just by reading these specs, I have a better understanding of what data and level of control is available via the OBD1 interface. Thanks again!

[1project2many]

When I bought my Z 20 years ago, it was hard to come by. Only a few people knew anything about it.

The more popular OBD1 stuff was hacked back then and software was available to reprogram EPROM's. The L98, many of the TBI applications, and the Syclone are among the known ecm's. ALDL protocol was figured out and information was around as well although the engine specific definition files I linked to didn't find their way to public forums until a little later. But the 94 LT1 PCM with it's flash programming was still new. Hypertech had hammered away at the GM seed/key routine enough to build their Power Programmers and I believe LT1 edit had been produced by a couple of guys using information gleaned from several sources. But you're right that most of the guys doing tuning were either hard core or had a degree in a technical field. It was definitely a fun time to be involved in the hobby.