Cadillac: cadillac, oil pressure switch, fuel pump relay

Question
I have a 1997 sedan ville cadillac when I start the motor the engine cranks for about 10-20 seconds then it starts. I took it to auto zone to have it diagnose but it shows no codes. I'm afraid if I continue using my car like this I mite mess the starter, do you have any suggestions on this problem.

Answer
As soon as you turn ON the ignition switch to ON position, Just before you turn the key to the start position when the engine starts to crank over, A 2 second battery voltage signal is sent from the computer to the fuel pump relay and then from the relay back to the fuel pump in the fuel tank. This runs the fuel pump for ONLY 2 seconds of which pressurizes the fuel system in preparation to start the engine.

Once the engine starts, The computer BYPASSES the fuel pump relay and  sends constant contionous battery voltage from the computer to the oil pressure switch of which is now CLOSED because the oil pressure is UP because the engine is running. Therefore the battery voltage flows from the computer, thru the oil pressure switch, back to the fuel pump to run the fuel pump constantly until you turn OFF the engine.
Therefore if your POSITIVE you are hearing that 2 second pump run just when you turn the ignition switch to the ON position ONLY, just before you turn the ignition key to the start position, I would have to say  you have a weak fuel pump upon initial start up and to have the fuel pressure tested..
If you are NOT hearing that 2 second fuel pump run, Then I would say that the fuel pump relay is defective or faulty computer..
If you are hearing the 2 second pump run then the computer may not be sending a constant signal  to the fuel pump either via a defective oil pressure switch or faulty ecm.