I've bought and assembled a DIYPNP, loaded firmware, and was able to load it with a base tune for my model year, 1993. I have an AEM wideband o2 gauge that comes with a bosch sensor, and the GM IAT sensor, both connected to the stock wiring harness, and the map sensor hooked up. In the car the DIYPNP powers on and connects, and from the log I've attached you can see most of the sensors are reading normal values, but the car will not start. Tunerstudio recognizes I'm cranking for about 1 second and then goes back to "not cranking" even if I still am. The log attached is the motor being turned over for about 4-5 seconds. I've also attached the tune file and project zip. Any help appreciated! I've been reading the forums here and the diyautotune info for a couple of months, so if you have any recommended threads to read here or other reading material for mega-squirt systems please let me know. Thanks.
Also, the motor will start to kick like it wants to start, but that's all it does.

 

I've gotten it to run now.

 

What were the issue and the fix?

I would be interested in how you figured it out.

 

Time for this threat to rise from the grave! I'm having a similar issue with my 91 and I'd be interested to hear what the fix was. Though looking at the post counts it seems like I'm grasping at straws here...