GM ALDL interface

[Frederic Breitwieser]

>I assume all I need for a test bench such as yours Fred is an ECM, wiring
>harness, and +12v power supply?

Yes, my test bed (put together in about 5 minutes) was:

(1) 12V 50A power supply
(1) Oscilloscope
(1) Buick FWD 3.8L ECM (same as GN, just the one I lucked out in having)
(1) ECM harness to engine harness (attaches to provide power and ALDL out)
(1) ECM harness for interior of car, which has the ALDL connector
(1) Garage floor to spread everything out (my workbench has four steering
columns on it right now)
(1) HomeMade Cable with transister circuit
(1) Notebook PC (Mine's an 8Mhz 286, monochrome display)

>I have an old Zenith computer, like an 8088 that is expendable.  Would that
>be suitable?

Yeah, absolutely, just have to make the timing loop smaller, it took me a
while to get the figure right, since I know the ECM pumps out code "12" (I
think) before and after each error code (I think its 12), so when numbers
started looking right, I ended up with some decent data.

The Q-Basic program that Sean written might be a bit slow on an 8088, but I
borrowed a Q-Basic compiler for DOS (circa 1987!!!) and compiled it and
kept testing.

I'll have a more tweeked version soon, and Sean volunteered to put the
compiled version on his website.  I won't have a chance to play with it
until the weekend, due to my working on a friggen stubber dial-in webserver
at the moment.


Frederic Breitwieser
Homebrew Automotive Mailing List
Bridgeport, CT 06606
http://www.geocities.com/MotorCity/Downs/4605/index.html
(Portable Webserver Link Address)

1989 AG Hummer 4-Door
1993 Supercharged Lincoln Continental
2000 Mid-Engine Sports Car <smile>

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