I’m having issues with an 1988 Nissan D21 truck 4 cyl tbi. It is flooding the motor and preventing starting. My biggest question is when you turn the key to the on position, but do not start it and the fuel pump pressurizes the system should the injectors turn on too or just the pump? I am fairly sure this is a computer issue as both injectors kick on during priming and spray at full force and the computer will not enter diagnostic mode.
Will the computer turn on the Check Engine Light before you try to start the truck? If the CEL does not come on, the computer will not enter diagnostic mode, and the injectors are kicking on with the key ‘on’ and not showing any signs of pulsing when the engine is cranked, you do indeed have a ECM problem. Just to eliminate one possibility disconnnect the injector plugs and see if the injectors stay off when the fuel pump is running.
Let us know what solves this condition.
It could also be a short in the wiring to the injectors. I think they are both pulsed together, so a single short to ground may cause both of them to open.