First off. I appreciate your help through this, as otherwise I would have never figured this out. Those diagrams are priceless.
The sender units are totally different. The opening for the lock ring is way smaller on the v8 unit. The v8 is all metal sender. 4.3 was plastic, 4.3 uses quick connects, v8 uses screw fittings. I was able pull the 4.3 pump out and put the dw200 in its place. I had cut an opening for the dw200 sock filter to stick out but it went in easily enough.
The whole 0-90 and 40-240, pcm control. No pcm control, was confusing, especially with the 97 year being the odd ball.
I found out the 97 4.3 pcm only uses the second fuel signal. Pin d. for accessories, it doesn't convert anything.
After testing the gauge with ground vs 12v and seeing the gauge oppose its reading. I grabbed couple AA batteries and - to ground and positive to gauge. The needle moved to 1/4 tank. So that gave merit to the thinking it needs a bolt signal not resistance to ground.
I then tried a bunch different configurations of the buffer wires. No luck.
I blew every cluster fuse there was in doing so. Lol
But the 5v signal was random and not always 5v. That stuck in my mind.
So after all this. I focused on that, and on the LS pcm I knew the oil sender wasn't being used. As I'm using the obs oil sender and wiring.
So I ran a wire from 5.3 blue pin 7 oil sender 5v reference to the buffer module.
She works!!!
I tested the buffer output wire to gauge and it doesn't change the ohm it sends out a 5.XX signal to the gauge. Which seems even more odd. Guessing the engineer for 97 was fired. Lol
Thanks again