Newbie ALDL question

[Ervinc90 at aol.com]

I have been reading the archives on aldl for about a month or so.  I went
ahead and built the ALDL interface that was posted which contained: a max232
chip 9 resistors, 4 diodes, 6 capacitors and a voltage regulator.  I have
downloaded the gcar2.exe and the pcmcomm program.

My question is this: Why am I not receiving continuous data in the monitor
mode with the gcar2 program on a 386 with dos 6.2?  

I have gotten spurts of data while checking for the connection with the ecm
and noticed that everytime I turn the ignition on and off a set of 00 appear
on the computer.  ( this leads me to believe that the max 232 chip is seeing
something??)  I have double checked the circuit several times and even rebuilt
a second from scratch.  I have tried this on a 91 corvette (ecm: 1227727) and
a 95 chev c1500 (don't recall the computer).  I also noticed another interface
diagram which utilized a 74ls07 instead of the transistors and resistors.  Is
this somthing worth trying?  I am a metallurgical engineer that knows a little
about circuits, but not enough to figure the problem out.

Thanks, 
Bill Carson