First let me say, I have two Walbro fuel pumps, not a AEM. That's my brothers 93TT that I have been working on for the last couple of months.
One phone call to Scott Taylor at Z Shack made sense out of what I was seeing on my fuel pressure gauge The pumps are set up as a Primary and Auxiliary. The auxiliary pressurizes the fuel system for starts, and supplements fuel, as needed during times of high demand. When the ignition is turned on the aux pump pressurizes the fuel system till it starts. Then, the Haltech turns on the primary and shuts down the aux pump. The primary pump is not coming on. That explains why fuel pressure drops all the way down about two seconds after it starts. I checked some of the wiring tonight and all looked good so far, but I have not checked under the hat yet or the relays yet. I hope I find something other then having to buy and install another pump. I'll update this when it's fixed.
14:35:41 11/12/23
