I built my MS with the BT adapter sold by EFI. I'm struggling with cold start gremlins cuz I'm a noob. I'm having a hell of a time getting a decent log of the first cold start because my BT connection keeps shitting out during cranking. My cold start is so bad that cranking is momentarily ceased. I'm wondering if this momentarily disrupts power to the BT antenna? The only way to reinstate the connection is to disable the connection in my laptop settings, re-find the BT device (which creates a new set of virtual ports), go into tunerstudio, & select the new virtual port.

I thought the BT was super clever, and I attached it directly to my MS, which is neatly tucked away under the carpet. I could pull it up & just resort to using the cable, but I'm curious if anyone else has resolved this issue.

 

I would guess the BT adapter resets from the voltage drop when cranking. If the cranking is so weak that the engine occasionally stops turning, it is possible the voltage drop also affects the MS. Obvious suspects to that are bad battery or shitty wiring, followed by a bad starter.

Try measuring the voltage (the feed to the Megasquirt or somewhere nearby), it shouldn't drop much below 9V or so.