The link below provides more detailed info on how the alt works and how to test it in detail.

http://www.autoshop101.com/forms/h8.pdf

If you look at the wiring diagram the engine controller is not in the circuit. The alt is basically isolated and via the alt regulator takes care of itself. The ign key turns the alt on.

Wonder if the alt is putting out too much current.

Check voltage at the red/green wire as the engine dies and determine if the voltage drops significantly.

Suppose you could bypass the ign switch. Run the red/green and yellow wire alt connections from the alt to the battery direct. This would remove out any of the cars other electrical circuits.

 

I haven't even made up a whole new wiring to the alternator, from the battery just to try to see if the problem was in the harness between the battery and the alternator I ran the big charge wire and the three little regulator wires direct to the battery and the problem remains. When the engine still quits the ignition coils still have 12 V going into them with the motor quits I also checked out the injectors that they still have 12 V going into the injectors . It seems like with the engine starts up and the alternator starts charging above 13 V the engine starts to shut down.