There are two wires going to each injector. Constant power (with ignition on) and the pcm sends a ground. Power should be a pink wire that is split to each injector. When you have the condition start, turn the engine off with ignition on and check the connector's pink wire for power. Likely you have power. This would mean that you have a break in the grounding wire from the pcm. Start removing the loom and find the break in the wire then repair and replace the loom.
Should be a straightforward fix. Hope that helps.
