Unfortunately, the injectors have 12v coming to them on red wires, and the wires going to the ECU are each different colors for each injector. The ECU grounds the circuit to fire the injector, so interrupting by grounding the signal will open the injector, not kill it. You need to interrupt the 12v coming in on the red wires. Go here and login with the username and password of tech/tech. Go to the bottom, "Auto Repair Reference Center Beta" and find vehicle and your wiring diagrams.
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