Are the internals (processors, connector plug wiring, etc.) of Red/Blue PCMs the same? I have both a 16168625 BBMX and a 16195925 BHRJ. The 8625 is from a '93 Chevy Sierra 4.3L (I believe) while the 5925 is for a '94 Olds Bravada 4.3L. I have seen a bunch of write-ups on the 8625 and, therefore, my plans are to use the 8625 in my '92 4x4 S-10. On the other hand, I can find nothing about the 5925. I am wondering if the only difference is the chip and not the physical internals.

I ask this because I am running into the same "no start/run" problem when I install both PCMs. In so doing, I am trying to determine if the issue to the no start/run is the PCM or the adapter that I have constructed as I learn about tuning.

Lastly, is it possible to turn the 5925 into the equivalent of an 8625 by reprogramming and installing a PROM?