I had a strange problem years ago where my Dart I had would run with an aftermarket ECU but with 2 new orange MP ECU's it would not run. Found out I had the pick-up coil wires crossed in the harness and when I changed them back right the car ran on all of the ECU modules. Seems the aftermarket ECU worked with the wires to the pick-up crossed but the factory MP ones had to have the wires right. Ron