Just some ideas running through my head... I remember reading that the fuel injector for the bosch L-jetronic system uses a batch fire sequence. ('83 turbo ecu) I do not remember if the injectors are fired all at once, or if there is two groups. I don't have access to my oscilliscope right now, so I can't test it to check. If anyone knows if it is one or two groups, let me know.
-jeremy-