Power cuts out
 

Hey, before I start I want to say that I already have some Conclusions as you will read soon but I just had a Surgery so I can't put any of them to the Test right now, thats why I write this.

Im having an issue with my 92 Turbo Miata.
When I set the Timing in Tuner Studio on "Fixed Timing" (Car runs fine on "Fixed Timing") and switched it back to "Use Table" and pressed "Burn" like I should, the Car died and lost all Electric power for a few Minute, sometimes Hours. It's like something grounded out.
As far as I know being on "Fixed Timing" cuts Power to the ECU and CAS and lets the Engine run on "Default settings". "Use Table" activates the ECU and CAS again. Could a Broken CAS Cause problems like that ? Or could there be a faulty Wire leading to the CAS which grounds out when the CAS resives Power again by switching to "Use Table". ???

I also sometimes have the Issue that The interior Engine Fuse wouldn't get any power resulting in the ECU, Fuel Pump and Main Relay also not powering on, meaning the Ignition would be on but the Car wouldn't Crank. When I had this for the first Time I put my Multimeter to the Engine Fuse, as soon as The Probe made contact with the Metal on the Fuse i Could hear a "Click" followed by the Fuel Pump turning On and my Laptop (Tuner Studio) connecting to the ECU.
Also my Gauge Cluster dosn't work. These Could potentially all be Linked.

I had these Issues for a while now and allready replaced some things with known working ones. These Include the Ignition Switch, the Main Relay and the Fuel Pump Relay.
All Grounds have been Checked and Cleaned and No Fuses are Blown

Im not a Mechanic or an Electrician but I Attached some Pictures of what I think is the Problem.

In Pic1 You can see that The Ignition Switch gives Power to The Engine Fuse ( Blue Line) which is linked to The Meter Fuse and the Ignition Coil. The Engine Fuse supplies The Main Relay (BLK-WHT Line). The Meter Fuse supplies the Instrument Cluster, which also isn't working.
Considering that the Ignition Switch is working, a faulty Wire or Connection here could explain why The Car sometimes wouldn't Crank and The Gauge Cluster dosn't work, right ?
https://cimg8.ibsrv.net/gimg/www.mia...e67f76d9f4.png
Pic1
In Pic2 You can see that the "ST SIG" Fuse is also linked to the Gauge Cluster, Megasquirt ECUs require you to remove this Fuse before Running them.Could removing this Fuse Cause Potential issues though ?
https://cimg4.ibsrv.net/gimg/www.mia...08ec72b2b1.png