1990 Corvette It doesn't start I went to start it and nothing happened I put a new fuel pump gasoline filter spark plugs MAF SENSOR?

a 1990 corvette that wont start. I have replaced the fuel pump, map sensor, ecm , checked for spark and fuel to the fuel rail

The Oil pressure switch can go bad and will not let the car start at all because the ECM has to see at least 3 psi while cranking or running to let car run. Next to distributor.