Engine codes; PC to General Motors ALDL interface

[m_mcdonald at marx.ENET.dec.com]

<snip>

> George M. Dailey (gmd at tecinfo.com) said:

> Does Diacom have and any idea about their massive following?

I hope that Rinda Technologies (maker of the DIACOM hardware/software
package) has a massive following.  DIACOM IMHO is an excellent product
and very fairly priced at about $300.

> The latest
> J.C. Witney catalog #586k (inside cover page) has an Auto Xray XP240 scanner
> for $280 complete, no PC needed. The illustration shows a two line display
> (32 characters). Interface cables are available for GM (king of autos), Ford
> :-}, and that other car maker ... Chrysler for only $29 each.  I do not own
> one, and I don't know anybody that owns one. I'd be willing to bet that it
> works as advertised.

My only experience with the Auto Xray scanner is reading its advertisement.
It may be OK for GM and Chrysler owners since it displays information from
their cars' serial data stream.  It only displays trouble codes for Ford
products.  This makes it by far the most expensive Ford code reader in
existence.

> I neglected to tell you folks out in DIY FI land, what my true reason was
> for wanting to read ALDL data.

> Here's my confession. I have constructed a mid engine, rear wheel driven
> sports car from scratch. The engine is a '85 PFI 3.8L Buick V6.  The plan is
> to transmit the ALDl data to a dedicated PC, peramanently mounted in the car
> and connected to a small VGA monitor. Software would convert the data to
> usefull information that would be displayed on the monitor.  Boom, no
> additional instruments needed and a wealth of data on demand. The car
> (Bianca) was designed to house a PC.  Think of her as a streached
> Lamborghini Contach with all the room and comfort of a full size '70's Olds.
> Data logging would also be utilized. The PC would also control some BODY
> functions. It's not that I'm to cheap to by Diacom or XP240 (I just might by
> the XP240) but, if I'm going to make this work I need to get some type of
> simple PC to ALDL communication established.

> Any help on the software end would be much needed.

I'll begin by congratulating George on his construction and enthusiasm.

As soon as you decide to *control* body (or any component) function from
a PC, you are in another ball game.  I believe that DIACOM uses some fairly
sophisticated programming to extract information from the data streams
(I think there are four streams, not just one) at the ALDL.  Learning
the many details of these data streams is a difficult task.  Learning
how to write a program to perform I/O at a PC's parallel port requires
a large amount of time for a beginner.  Perhaps you can take advantage
of what DIY_EFI members have done to control the engine functions and
modify this software?

Other members may have advice and suggestions, more promising than mine
are, to George.  If so, speak up!
 
> thanks'

> George M. Dailey  gmd at tecinfo.com

Marll McDonald   KB1AGM
m_mcdonald at marx.enet.dec.com