Alright,

I have swapped an LT-1 into an older car. The motor, trans, harness, and pcm are all donated from a 94 caprice police interceptor. I have done some research on here already and found that everyone blames the VATS for the issue I'm having. the car will start and run for about 4-5 seconds and then no matter what happens, die. you can immidietly restart it, and it will do the same thing over and over again. The fuel pump is not part of the factory wiring, and thusly cannot be effected by the oil pressure sender. The key setup in the original 'cruiser' did not have that little black resister, just a stamped key, with nothing else to it. I remember because I could go to ace hardware and get 5 made for 3 dollars, and I loved it. But that doesn't mean that there wasn't something just built in somewhere to emulate a resistance as a bypass from when they made it into a police car.

Now, I've hacked this harness a bit, and possibly unknowingly removed such a module. what can I do to trick it.

 

If it were a VATS issue, the car wouldn't start at all. VATS disables the starter enable relay (so no starter function), and even if that part was bypassed, VATS also disables the fuel injectors, so it wouldn't run even if the starter did turn.

Sounds like an issue with the pump priming, but not running after the car starts. Get someone to start the car for you, while you are under the ar with ear to tank. See if the fuel pump keeps running after the car starts.