I have a 1988 base Camaro t top, the original 2.8l v6 seized up so I put another one in from 1992 c10 pick up, it had carburetor in take on it so I put my fuel injected system on it, I can get the battery to charge how ever the fuel pump turns on when the ignition is off and turns off when I turn the ignition on it won’t start cause the fuel pump turns off when I try to start it I thought it was a pressure issue but I ultimately killed the battery I am getting fuel to the injectors it just doesn’t want to stay running any help on this would be greatly appreciated

 

Just to test to see if the ecm is controlling the relay backwards. Unplug the relay and see if you her the pump key off. I believe the ecm controls a green with white stripe wire on the relay. Key on it should have 12v key off zero volts. If this is backwards the ecm might be faulty. I have never heard of the ignition controlling the relay backwards .

 

 

It will shut off if you unplug it no matter what. Like tuned said, you will be looking for a green/white stripe wire in the relay plug. Test it for voltage both key run and key off to the Black/white stripe wire or a chassis ground. You should see 12v key on prime for 2 seconds then 0v after prime. If it is 12v off there is some kind of cross short or ECM failure.

Is there any non factory wiring in this area? I can also see a possibility of the connections being mixed up causing this. You also have an oil pressure switch that should switch the pump on that bypasses the relay altogether. It would be interesting to see if you jumped that closed with the key on.

 

 

If you have a harbor freight close to you a bolt ohm meter there is cheap or free if you can get a coupon.. the ecm is under the passengers side dash. You should have a 1227302 ecm.
Instead of throwing parts at the car you should really diagnose it properly.