Been there, done that. I taped a couple of wires to a 9v battery and with the ground from the battery pinned to the injector ground at the ECU harness, I probed the positive pins. You'll hear a definite clicking. You can test this way directly at the injector(as I recall, polarity doesn't matter), but that doesn't mean you don't have a bad connector. A word of caution: I jumped wires from the connector to the injector while probing the ECU. It gave me a false positive. The problem was, when I reconnected the injector connector, the short would reoccur. When the connector was pulled, it would position itself such that the short was closed. Major gaslighting. It was providing a good continuity test with the connector pulled.
