James,
With all the thrashing around you've done in the bowels of the engine - is it possible that some SAI component is reinstalled backwards by accident?
I ask because I mark all my components with Paint Pen Marker just to help my feeble memory.
These are the only ones that seem to work. I use them for plasma cutting and welding also.
https://www.amazon.com/Super-Met-Al-1296-1324-Squeeze-Action/dp/B000KL7OYO
The Sharpie version I found to be useless.