Hello if you are still interested.
My Morgan no longer opened the immobilizer.
After days of searching.
The lines on the coil were both off and were only on the solder joint.
The cable connecting the immobilizer to the coil is very thin. The copper is dark
oxidized. The connectors on the imobolizer were crimped very poorly.
I took a good 20 AWG cable and the plugs are now gold plated.
Now the immobilizer opens at 12.3 volts. The key is 6 cm away from the lock and opens the immobilizer.
So if you have your coil as close to the key as possible, you have a problem. Because it is not necessary if the system works correctly.
I hope you understand it because my english is not good.
Best regards Ralf